front axle & suspension
Overview
Front Suspensions
The Blue Bird All American is equipped with one of two front suspension systems:
Hendrickson™ SofTek.™ The Softek front suspension is a three parabolic leaf spring
configuration, and is standard equipment on the Forward Engine All American.
Hendrickson™ AirTek.™ The Airtek front suspension is an air spring suspension used
on the Forward Engine All Americans equipped with air suspension option. Two leveling valves maintain ride height at varying axle loads.
Axles
Hendrickson™ SteerTek. The Forward Engine All American is equipped with Hendrickson SteerTek front axles. The SteerTek axle includes an anti-lock brake system
and is used in 13,200 and 14,600 lb. capacities on All Americans.
Appendixes & Other References
Appendix 1. AirTek & SofTek. Hendrickson Publication number 17730-248 covers
maintenance, adjustment, and component replacement information on the SofTek
leaf spring suspension. Please note that this Hendrickson publication also incorporates information on Hendrickson’s SteerTek front axle and AirTek front air suspension.
35
Hendrickson Identification
The specific Hendrickson axle model installed may be
identified by refering to the axle numbers etched near the
center front of the axle’s main beam.
Also See: The Hydraulc Brakes chapter of this manual includes a procedure for removing the front disc rotor/hub assembly.
Maintenance
Maintenance of the front axle and suspension consists of periodic general inspection,
checking tightness of fasteners, and lubricating grease fittings. Refer to the maintenance charts in this chapter (also included in the Specs & Maintenance chapter) for
maintenance inspection intervals. The exploded illustrations in this chapter include
torque specifications.
Hendrickson
airtek / softek
1
APPENDIX
L
SERVICE MANUAL
36
A
C
B
B
D
Right Side Shown
Left Side Symetrical
unless otherwise noted.
G
G
G
00106294m
G
SofTek Front Suspension
L
Front axle & suspension
Torque Requirements
key description
A Front Hanger Pivot
B Shackle Bracket Pivot
CUpper Shock
DLower Shock
ELinkage Rod Assy Locknut
FLeveling Valve Lockout
G Axle Clamp Group Nuts
H Air Spring Mounting Stud Locknuts (All)
J Shackle Bracket Locknuts
torque +- 5%
300 ft.lbs.
300 ft.lbs.
125 ft.lbs.
125 ft.lbs.
11 ft.lbs.
8 ft.lbs.
295 ft.lbs.
25 ft.lbs.
120 ft.lbs.
37
Front Axle Alignment Specs
Caster:
Camber:
Cross Caster:
Toe In:
4.5° ± 1.5° positive
± 1.0° (left & right) 2 Total
1.00° max
0.060” ± .030”
L
SERVICE MANUAL
F
38
H
H
A
J
J
E
B
B
C
SHOCK LENGTH
@ RIDE HT:
FE=17.25±.25
E
H
D
G
AirTek Front Air Suspension
L
00106294m
OUTBOARD
STUD ONLY
Front axle & suspension
Torque Requirements
key description
A Front Hanger Pivot
B Shackle Bracket Pivot
CUpper Shock
DLower Shock
ELinkage Rod Assy Locknut
FLeveling Valve Lockout
G Axle Clamp Group Nuts
H Air Spring Mounting Stud Locknuts (All)
J Shackle Bracket Locknuts
torque +- 5%
300 ft.lbs.
300 ft.lbs.
125 ft.lbs.
125 ft.lbs.
11 ft.lbs.
8 ft.lbs.
295 ft.lbs.
25 ft.lbs.
120 ft.lbs.
39
Front Axle Alignment Specs
Caster:
Camber:
Cross Caster:
Toe In:
4.5° ± 1.5° positive
± 1.0° (left & right) 2 Total
1.00° max
0.060” ± .030”
Ride Height Adjustment
Ride height may be verified by measuring either shock length or air spring height:
1. With leveling valve and linkage installed as shown and air system at 80 PSI or
greater, right hand side shock length from centerline of eye to centerline of
eye should be 17.25” ± .25” for Forward Engine models.
2.If adjustment is required, loosen leveling valve body mounting fasteners from
the frame rail and rotate valve counter-clockwise or clockwise to lengthen or
shorten shock dimension.
3. Tighten valve mounting fasteners to 8 ft. lbs.
4. Remove vertical link lower grommet from stud on spring pad, lower valve
horizontal arm, and release all air from bag.
5. Reconnect link and verify shock length according to step 1. If measurement
is not correct, repeat steps 1 thru 5 until proper ride height is achieved.
6. Repeat steps 1 thru 5 for left hand side.
L
Front Axle & Suspension
Interval:
Months/Miles
•
•
•
•
•
•
•
•
Torque shock mounting bolts
Air Suspension
Inspect visually
Check axle to suspension fasteners
Lubricate steering grease fittings
Inspect pin lock bolts
Inspect shackle bracket pivot bolt
Torque shock mounting bolts
Inspect air spring cushions
Check air spring fasteners
Inspect shocks
Check suspension height
Check ride height control valve bolts
L
12 / 12,000
operation
Spring Suspension
Inspect visually
Check U-bolt torque
Lubricate steering grease fittings
Inspect spring pin lock bolts
Inspect shackle bracket pivot bolt
Inspect shocks
6 / 6,000
40
first 1000 miles
whichever
occurs first
•
•
•
•
•
•
•
•
•
•
•
•
notes
Check for visual damage. See Hendrickson publication 17730-248.
Tighten to 285–305 ft. lbs (32–34 Nm).
Use NLGI #2 EP or equivalent.
Tighten to 380–420 ft. lbs. (515–569 Nm).
Tighten to 380–420 ft. lbs. (515–569 Nm).
Check for signs of leaks, wear, or damage.
TIghten to 215 ft. lbs. (25 Nm).
Check for wear, damage, misalignment. See Hendrickson publication 17730-248.
Tighten to 285–305 ft. lbs (32–34 Nm).
Use NLGI #2 EP or equivalent. Lube with suspension loaded.
Tighten to 380–420 ft. lbs. (515–569 Nm).
Tighten to 380–420 ft. lbs. (515–569 Nm).
TIghten to 215 ft. lbs. (25 Nm).
Check for wear, abrasions, cuts, or other damage
Check for signs of leaks, wear, or damage.
Shock length, eye to eye: 18.5” ± .25”. (470 ± 6mm).
TIghten to 8–10 ft. lbs. (11–14 Nm).
Front axle & suspension
SUBJECT: AIRTEK® & SOFTEK
Service Instructions for
Blue Bird Buses
LIT NO: 17730-248
DATE: February
January 2008
DATE:
2007 REVISION:
REVISION:DC
®
41
h
This publication is also available at
www.hendrickson-intl.com
di k
i tl
Bl
Airtek / Softek Suspension: Appendix 1
AIRTEK® & SOFTEK®
Bi d B
17730 248
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42
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1
APPENDIX
Front axle & suspension
43
TABLE OF CONTENTS
Section 1
Introduction . . . . . . . . . . . . . . . . . . . . . . 2
Section 2
Product Description . . . . . . . . . . . . . . . . 3
Section 3
Important Safety Notice . . . . . . . . . . . . . 6
Section 4
Special Tools . . . . . . . . . . . . . . . . . . . . 11
Section 5
AIRTEK® • SOFTEK® for Blue Bird Buses
January 2008
Rev. D
Section 9
Parts Lists
For Vision Buses
AIRTEK – 10K Capacity . . . . . . . . . . . . . . 12
SOFTEK – 8K/10K Capacity . . . . . . . . . . . 14
For All American Buses
AIRTEK – 14.6K Capacity. . . . . . . . . . . . . 16
SOFTEK – 13.2K/14.6K Capacity . . . . . . . 18
Right Hand Drive Axle . . . . . . . . . . . . . . . 20
Section 6
Section 7
Towing Procedure . . . . . . . . . . . . . . . . 21
Preventive Maintenance
Component Inspection. . . . . . . . . . . . . . . . . 24
Lubrication Intervals . . . . . . . . . . . . . . . . . . 25
Kingpin Lubrication. . . . . . . . . . . . . . . . . . . 25
Tie Rod End Lubrication. . . . . . . . . . . . . . . . 26
Tie Rod End Inspection . . . . . . . . . . . . . . . . 27
Clamp Group Re-torque Interval . . . . . . . . . . 29
Tire Inspection . . . . . . . . . . . . . . . . . . . . . . 29
Axle Wrap Liner Inspection. . . . . . . . . . . . . . 32
Shock Absorber Inspection. . . . . . . . . . . . . . 32
Kingpin Bushing Inspection . . . . . . . . . . . . . 34
Steering Knuckle Inspection . . . . . . . . . . . . . 35
Shackle Thrust Washer Inspection . . . . . . . . 36
Front Hanger/Rear Shackle Plate
Surface Paint Wear . . . . . . . . . . . . . . . . . 37
Section 8
Section 10
Alignment & Adjustments
AIRTEK Plumbing Diagrams
10K Capacity . . . . . . . . . . . . . . . . . . . . . . . 94
14.6K Capacity . . . . . . . . . . . . . . . . . . . . . 95
Alignment Definitions . . . . . . . . . . . . . . . . . 38
Inspection Prior to Alignment . . . . . . . . . . . . 40
Front Wheel Alignment . . . . . . . . . . . . . . . . 41
AIRTEK Ride Height Adjustment . . . . . . . . . . 43
AIRTEK Height Control Valve Test . . . . . . . . . 45
Steering Stop . . . . . . . . . . . . . . . . . . . . . . . 46
Toe Setting . . . . . . . . . . . . . . . . . . . . . . . . . 46
Spring Eye Re-torque. . . . . . . . . . . . . . . . . . 48
17730-248
Component Replacement
Fasteners. . . . . . . . . . . . . . . . . . . . . . . . . . 50
Spacers . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
AIRTEK Height Control Valve. . . . . . . . . . . . . 50
AIRTEK Air Spring . . . . . . . . . . . . . . . . . . . . 53
AIRTEK Front Leaf Spring Frame Hanger . . . . 57
SOFTEK Front Leaf Spring Frame Hanger . . . . 58
AIRTEK Rear Shackle Frame Bracket . . . . . . . 59
SOFTEK Rear Shackle Frame Bracket. . . . . . . 60
SOFTEK Rubber Axle Stop . . . . . . . . . . . . . . 62
Thrust Washer . . . . . . . . . . . . . . . . . . . . . . 62
AIRTEK Leaf Spring Assembly. . . . . . . . . . . . 63
SOFTEK Leaf Spring Assembly . . . . . . . . . . . 66
Front Leaf Spring Eye Bushing . . . . . . . . . . . 68
Shock Absorber . . . . . . . . . . . . . . . . . . . . . 68
AIRTEK Bottom Axle Wrap . . . . . . . . . . . . . . 70
SOFTEK Bottom Axle Wrap. . . . . . . . . . . . . . 71
AIRTEK Top Axle Wrap (In Chassis) . . . . . . . 72
SOFTEK Top Axle Wrap (In Chassis) . . . . . . . 75
AIRTEK Front Axle Assembly. . . . . . . . . . . . . 77
SOFTEK Front Axle Assembly . . . . . . . . . . . . 78
STEERTEK Axle Removal . . . . . . . . . . . . . . . 79
STEERTEK Axle (Removed from Chassis). . 80
Steering Knuckle Disassembly . . . . . . . . . 83
Kingpin Preparation & Measurement . . . . . 84
Kingpin Bushing Removal . . . . . . . . . . . . 86
Steering Knuckle Bore Measurement . . . . . 87
Kingpin Bushing Installation. . . . . . . . . . . 87
Kingpin Bushing Reaming . . . . . . . . . . . . 88
Kingpin Seal Installation . . . . . . . . . . . . . 89
Steering Knuckle Assembly. . . . . . . . . . . . 90
Tie Rod End and Cross Tube . . . . . . . . . . . . 92
Appendix
Reference Material . . . . . . . . . . . . . . . . . . A-97
Trouble Shooting Guide . . . . . . . . . . . . . . A-98
Torque Specifications . . . . . . . . . . . . . . . A-100
Front Alignment Specifications. . . . . . . . . A-108
Technical Procedure Publication Quiz . . . . . . . . . . . A-110
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APPENDIX
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
SECTION 1
Introduction
This publication is intended to acquaint and assist maintenance personnel in the preventive maintenance, service, repair and rebuild of the following Hendrickson equipment as
installed on applicable Blue Bird Buses:
44
NOTE
■
AIRTEK® — An integrated front air suspension with the STEERTEK axle.
■
SOFTEK® — An integrated steel spring mechanical suspension with the STEERTEK axle.
■
STEERTEK — A lightweight, formed and robotically welded steer axle assembly.
Use only
Hendrickson Genuine parts for servicing this suspension system.
It is important to read and understand the entire Technical Procedure publication prior to
performing any maintenance, service, repair, or rebuild of the product. The information in
this publication contains parts lists, safety information, product specifications, features,
proper maintenance, service, repair and rebuild instructions for the AIRTEK/SOFTEK
Suspension and the STEERTEK axle.
A Technical Procedure Quiz has been included at the back of this publication. Hendrickson
will provide personalized AIRTEK/SOFTEK Technical Procedure Quiz Achievement Certificate
to candidates scoring 80% or higher on the test. Simply complete the test and fill in the
enclosed answer sheet or write your answers on a separate sheet with the return address,
name, phone number, and company name as it will appear on the award to:
Hendrickson
ATTN: Truck Marketing Test Quiz Assessment
800 S. Frontage Road
Woodridge, Illinois 60517
Hendrickson reserves the right to make changes and improvements to its products and
publications at any time. Contact Hendrickson Tech Services at 630-910-2800 or e-mail
techservices@hendrickson-intl.com for information on the latest version of this manual.
The latest revision of this publication is also available online at
www.hendrickson-intl.com.
Introduction
L
1
APPENDIX
2
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
SECTION 2
Product Description
BLUE BIRD VISION BUSES
FIGURE 2-1
AIRTEK® Air Suspension System
Capacity: 10,000 pounds
FIGURE 2-2
SOFTEK® Mechanical Suspension System
45
Capacity: 8,000/10,000 pounds
BLUE BIRD ALL AMERICAN BUSES
FIGURE 2-3
AIRTEK® Air Suspension System
Capacity: 14,600 pounds
FIGURE 2-4
SOFTEK® Mechanical Suspension System
Capacity: 13,200/14,600 pounds
RIGHT HAND DRIVE AXLE
FIGURE 2-5
17730-248
3
Product Description
1
APPENDIX
L
SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
STEERTEK — The box-shaped design provides a stiffer axle and resists torsional,
longitudinal and vertical loads more effectively than traditional axle beams. Together with
the front limbs of the leaf springs, the robotically welded axle beam forms a torsion system,
enhancing roll stability characteristics and improving handling.
46
Axle clamp group — The patented clamp group provides four-sided clamping pressure.
The Clamp Group consists of the following:
■
■
■
Top Axle Wrap
Top Axle Wrap Liner
Top Spring Pad
■
■
■
Bottom Axle Wrap
Bottom Axle Wrap Liner
¾" Bolts, Washers and Locknuts
Adjustable tie rod —To help maximize tire life, the tie rod easily adjusts toe-in/out.
Steering knuckles — The steering and tie rod arms are integrated for increased strength
and reduced weight. The unique steering knuckle packaging delivers a maximum of 50°
wheel cut. The two piece knuckle design makes servicing the kingpin bushings easier.
AIRTEK — Winner of the 2001 Automotive News and Cap Gemini Ernst & Young PACE
Award for Product Innovation. AIRTEK is an integrated front air suspension and robotically
welded steer axle that work together to form an integrated torsion system. Utilizing a
system approach, Hendrickson has engineered and optimized the following components
to form a system delivering ride, stability and handling characteristics with reduced weight
and maintenance.
Air springs — Exclusive to Hendrickson, the lightweight air springs deliver a soft ride.
The air springs are engineered to support 78% of the vertical load while providing a
low spring rate. The quick “snap” design for the 10,000 pound capacity, the bolt on
design for the 14,600 pound capacity, and the “push-to-connect” air supply design
also provide fast and easy removal and installation.
Leaf spring assembly — With its innovative design, the leaf spring provides superior
stability, performance and a soft ride. The patented leaf spring shares loads with the air
spring. Durable rubber front and patented rear bushings are greaseless and only
require periodic inspections.
SOFTEK — is an integrated front mechanical suspension and robotically welded steer
axle that work together to form an integrated torsion system. Utilizing a system approach,
Hendrickson has engineered and optimized the following components to form a system
delivering ride, stability and handling characteristics with reduced weight and
maintenance.
Leaf spring assembly — With its innovative design, the leaf spring provides superior
stability, performance and a soft ride. Durable rubber front and patented rear bushings
are greaseless and only require periodic inspections.
Shock absorbers — AIRTEK/SOFTEK utilizes premium shocks that have been tested and
tuned specifically for the suspension system.
Frame brackets — Optimized design delivers weight reduction and proven durability. The
front and rear frame brackets are common between the SOFTEK and AIRTEK suspensions.
Product Description
L
1
APPENDIX
4
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
TECHNICAL NOTES
1.
AIRTEK and SOFTEK are approved for 100% on-highway use; other applications must be preapproved by Hendrickson Sales Engineering. System capacity rating for the suspension
represents maximum loads on tires at ground level.
2
The STEERTEK axle for the Vision is available with 69" kingpin intersection (KPI). The STEERTEK
axle for the All American is available with 71" kingpin intersection (KPI).
3.
AIRTEK suspension weight includes frame and shackle bracket assemblies, main springs, bushings, air springs and air spring bracket, height control system, shocks, upper shock brackets
and axle clamp group.
4.
SOFTEK suspension weight includes frame and shackle bracket assemblies, steel leaf springs,
bushings, shocks, upper shock brackets and axle clamp group.
5.
STEERTEK axle weight includes the axle beam, knuckle/steering arm assemblies and tie rod
assemblies.
6.
AIRTEK and SOFTEK are integral to and available exclusively with the STEERTEK axle. This system is anti-lock braking system (ABS) ready. STEERTEK is compatible with most industry
standard wheel ends and brakes. Contact OEM for more information.
7.
The STEERTEK axle product identification is etched on the center front of the axle beam providing the following information:
■
Axle part number: Identifies the features of the axle beam.
■
Axle assembly number: Identifies the complete assembly, which includes the steering
knuckles and bracket assemblies.
47
FIGURE 2-6 Front view of STEERTEK axle showing approximate location of Product Identification.
17730-248
5
Product Description
1
APPENDIX
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
SECTION 3
Important Safety Notice
Proper maintenance, service and repair are important to the reliable operation of the suspension. The procedures recommended by Hendrickson and described in this technical
publication are methods of performing such maintenance, service and repair.
The warnings and cautions should be read carefully to help prevent personal injury and to
assure that proper methods are used. Improper maintenance, service or repair may
damage the vehicle, cause personal injury, render the vehicle unsafe in operation, or void
the manufacturer's warranty.
Failure to follow the safety precautions in this manual can result in personal injury and/or
property damage. Carefully read and understand all safety related information within this
publication, on all decals and in all such materials provided by the vehicle manufacturer
before conducting any maintenance, service or repair.
48
EXPLANATION OF SIGNAL WORDS
Hazard “Signal Words” (Danger-Warning-Caution) appear in various locations throughout
this publication. Information accented by one of these signal words must be observed to
help minimize the risk of personal injury to service personnel, or possibility of improper
service methods which may damage the vehicle or render it unsafe.
This is the safety alert symbol. It is used to alert you to potential personal injury
hazards. Obey all safety messages that follow this symbol to avoid possible
injury or death.
Additional ‘Notes’ or ‘Service Hints’ are utilized to emphasize areas of procedural importance and provide suggestions for ease of repair. The following definitions indicate the use
of these signal words as they appear throughout the publication.
INDICATES AN IMMINENTLY HAZARDOUS SITUATION WHICH, IF NOT AVOIDED, WILL RESULT IN
SERIOUS INJURY OR DEATH.
INDICATES A POTENTIAL HAZARDOUS SITUATION WHICH, IF NOT AVOIDED, CAN RESULT IN
SERIOUS INJURY OR DEATH.
INDICATES A POTENTIAL HAZARDOUS SITUATION WHICH, IF NOT AVOIDED, MAY RESULT IN
MINOR OR MODERATE INJURY, OR PROPERTY DAMAGE.
NOTE
An operating procedure, practice condition, etc. which is essential to emphasize.
SERVICE HINT
A helpful suggestion, which will make the servicing being performed a little easier
and/or faster.
Also note that particular service operations may require the use of special tools designed
for specific purposes. These special tools can be found in the Special Tools Section of this
publication.
Important Safety Notice
L
1
APPENDIX
6
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
SAFETY PRECAUTIONS
FASTENERS
LOOSE OR OVER TORQUED FASTENERS CAN CAUSE COMPONENT DAMAGE, LOSS OF VEHICLE
CONTROL, PROPERTY DAMAGE, OR SEVERE PERSONAL INJURY. MAINTAIN CORRECT TORQUE
VALUE AT ALL TIMES. CHECK TORQUE VALUES ON A REGULAR BASIS AS SPECIFIED.
49
AIR SPRINGS
AIR SPRING ASSEMBLIES MUST BE DEFLATED PRIOR TO LOOSENING ANY CLAMP GROUP
HARDWARE. UNRESTRICTED AIR SPRING ASSEMBLIES CAN VIOLENTLY SHIFT. DO NOT INFLATE AIR
SPRING ASSEMBLIES WHEN THEY ARE UNRESTRICTED. AIR SPRING ASSEMBLIES MUST BE
RESTRICTED BY SUSPENSION OR OTHER ADEQUATE STRUCTURE. DO NOT INFLATE BEYOND
PRESSURES RECOMMENDED BY AIR SPRING MANUFACTURER, CONTACT HENDRICKSON
TECHNICAL SERVICES FOR DETAILS. IMPROPER USE OR OVER INFLATION MAY CAUSE AIR SPRING
ASSEMBLIES TO BURST, CAUSING PROPERTY DAMAGE AND/OR SEVERE PERSONAL INJURY.
WHEN SERVICING THE VEHICLE OR ATTACHING AN AIR SPRING AND THE VEHICLE IS ON THE
GROUND, PRIOR TO AIRING THE SUSPENSION SYSTEM MAKE CERTAIN THE AIR SPRING
LOCATOR IS INDEXED INTO THE UPPER AIR SPRING BRACKET PROPERLY, AND THE AIR
SPRING IS FULLY SEATED ON THE SPRING TOP PAD. FAILURE TO FOLLOW THESE
INSTRUCTIONS CAN RESULT IN PREMATURE AIR SPRING FAILURE, CAUSE PERSONAL INJURY,
OR PROPERTY DAMAGE.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
LOAD CAPACITY
ADHERE TO THE PUBLISHED CAPACITY RATINGS FOR THE SUSPENSIONS. ADD-ON AXLE
ATTACHMENTS (I.E. SLIDING FIFTH WHEELS) AND OTHER LOAD TRANSFERRING DEVICES CAN
INCREASE THE SUSPENSION LOAD ABOVE THE RATED AND APPROVED CAPACITIES WHICH
CAN RESULT IN FAILURE AND LOSS OF VEHICLE CONTROL, POSSIBLY CAUSING PERSONAL
INJURY OR PROPERTY DAMAGE.
MODIFYING COMPONENTS
DO NOT MODIFY OR REWORK PARTS. DO NOT SUBSTITUTE PARTS OF THE SUSPENSION OR
AXLE COMPONENTS, USE OF A MODIFIED OR REPLACEMENT PARTS NOT AUTHORIZED BY
HENDRICKSON MAY NOT MEET HENDRICKSON’S SPECIFICATIONS, AND CAN RESULT IN
FAILURE OF THE PART, LOSS OF VEHICLE CONTROL, AND POSSIBLE PERSONAL INJURY OR
PROPERTY DAMAGE. USE ONLY HENDRICKSON AUTHORIZED REPLACEMENT PARTS, DO NOT
MODIFY PARTS WITHOUT AUTHORIZATION FROM HENDRICKSON.
SHOCK ABSORBERS
THE SHOCK ABSORBERS ARE THE REBOUND TRAVEL STOPS FOR THE SPRINGS. ANYTIME THE
FRONT AXLE ON AN AIRTEK SUSPENSION IS SUSPENDED IT IS MANDATORY THAT THE SHOCK
ABSORBERS REMAIN CONNECTED. FAILURE TO DO SO CAN CAUSE THE AIR SPRINGS TO
EXCEED THEIR MAXIMUM LENGTH, POSSIBLY CAUSING THE AIR SPRINGS TO SEPARATE FROM
THE PISTON, OR CAUSE A REVERSE ARCH IN THE STEEL LEAF SPRINGS, POSSIBLY RESULTING
IN PREMATURE STEEL LEAF SPRING FAILURE.
17730-248
7
Important Safety Notice
1
APPENDIX
L
SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
TORCH/WELDING
DO NOT USE A CUTTING TORCH TO REMOVE ANY ATTACHING FASTENERS. THE USE OF HEAT
ON SUSPENSION COMPONENTS WILL ADVERSELY AFFECT THE STRENGTH OF THESE PARTS.
A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN THE LOSS OF VEHICLE CONTROL
AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
50
EXERCISE EXTREME CARE WHEN HANDLING OR PERFORMING MAINTENANCE IN THE AREA OF
THE SPRING ASSEMBLY AND AXLE. DO NOT CONNECT ARC WELDING GROUND LINE TO THE
SPRING ASSEMBLY OR AXLE. DO NOT STRIKE AN ARC WITH THE ELECTRODE ON THE SPRING
ASSEMBLY OR AXLE. DO NOT USE HEAT NEAR THE SPRING ASSEMBLY OR AXLE. DO NOT NICK
OR GOUGE THE SPRING ASSEMBLY OR AXLE. SUCH IMPROPER ACTIONS CAN CAUSE DAMAGE
TO THE SPRING ASSEMBLY OR THE AXLE CAN FAIL, AND CAN CAUSE LOSS OF VEHICLE
CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
OFF ROADWAY TOWING
WHEN A VEHICLE IS DISABLED AND EQUIPPED WITH A STEERTEK AXLE, CARE MUST BE TAKEN
TO ENSURE THERE IS NO DAMAGE TO THE SUSPENSION WHEN TOWING THE VEHICLE. THE
USE OF A TOW STRAP IS NECESSARY TO TOW A DISABLED VEHICLE INTO A REPAIR FACILITY
PARKING LOT INTO THE SHOP BAY. THE TOW STRAPS SHOULD BE CONNECTED TO THE TOW
HOOKS PROVIDED BY THE MANUFACTURER AT THE FRONT OF THE BUMPER. IF THE USE OF
TOW HOOKS IS NOT AN OPTION THEN A TOW STRAP MAY BE WRAPPED AROUND THE FRONT
AXLE (SEE FIGURE 3-1) IN A MANNER THAT IS ACCEPTABLE FOR TOWING THE VEHICLE INTO
THE SHOP. DO NOT USE A TOW CHAIN AROUND THE FRONT AXLE OR WITH A SINGLE POINT
LOCATION TO TOW THE VEHICLE, DOING SO WILL DAMAGE THE AXLE, SEE FIGURE 3-2. FOR
DETAILED TOWING INSTRUCTIONS FOR ON-HIGHWAY TOWING SEE SECTION 6.
FIGURE 3-1 ACCEPTABLE
FIGURE 3-2 NOT ACCEPTABLE
PROCEDURES AND TOOLS
A MECHANIC USING A SERVICE PROCEDURE OR TOOL WHICH HAS NOT BEEN RECOMMENDED
BY HENDRICKSON MUST FIRST SATISFY HIMSELF THAT NEITHER HIS SAFETY NOR THE
VEHICLE’S SAFETY WILL BE JEOPARDIZED BY THE METHOD OR TOOL SELECTED. INDIVIDUALS
DEVIATING IN ANY MANNER FROM THE INSTRUCTIONS PROVIDED ASSUME ALL RISKS OF
CONSEQUENTIAL PERSONAL INJURY OR DAMAGE TO EQUIPMENT INVOLVED.
PERSONNEL PROTECTIVE EQUIPMENT
ALWAYS WEAR PROPER EYE PROTECTION AND OTHER REQUIRED PERSONAL PROTECTIVE
EQUIPMENT TO HELP PREVENT PERSONAL INJURY WHEN YOU PERFORM VEHICLE
MAINTENANCE, REPAIR OR SERVICE.
Important Safety Notice
L
1
APPENDIX
8
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
SUPPORT THE VEHICLE PRIOR TO SERVICING
PLACE THE VEHICLE ON A LEVEL FLOOR AND CHOCK THE WHEELS TO HELP PREVENT THE
VEHICLE FROM MOVING. NEVER WORK UNDER A RAISED VEHICLE SUPPORTED BY ONLY A
FLOOR JACK. ALWAYS SUPPORT A RAISED VEHICLE WITH SAFETY STANDS. BLOCK THE
WHEELS AND MAKE SURE THE UNIT WILL NOT ROLL BEFORE RELEASING BRAKES. A JACK CAN
SLIP OR FALL OVER. SERIOUS PERSONAL INJURY CAN RESULT.
51
AXLE
AXLE CAMBER IS NOT ADJUSTABLE. DO NOT CHANGE THE AXLE CAMBER ANGLE OR BEND
THE AXLE BEAM. BENDING THE AXLE BEAM (SEE FIGURE 3-3) TO CHANGE THE CAMBER
ANGLE WILL DAMAGE THE AXLE AND REDUCE AXLE STRENGTH, AND WILL VOID
HENDRICKSON'S WARRANTY. A BENT AXLE BEAM CAN CAUSE LOSS OF VEHICLE CONTROL,
POSSIBLY CAUSING PERSONAL INJURY OR PROPERTY DAMAGE.
FIGURE 3-3
REPLACE ANY SAFETY DECALS THAT ARE FADED, TORN, MISSING, ILLEGIBLE, OR OTHERWISE
DAMAGED. CONTACT HENDRICKSON TO ORDER REPLACEMENT LABELS.
STEERTEK IS A UNIQUE AXLE, IN THAT THE KINGPIN IS CRYOGENICALLY INSTALLED IN THE
AXLE. THE KINGPIN IS A NON-REPLACEABLE COMPONENT OF THE AXLE ASSEMBLY. DO NOT
TRY TO REMOVE THE KINGPIN. IF THE KINGPIN SHOWS SIGNS OF MOVEMENT, CONTACT THE
HENDRICKSON TECH SERVICES DEPARTMENT.
THE REPAIR OR RECONDITIONING OF SUSPENSION OR AXLE COMPONENTS IS NOT ALLOWED
AS SHOWN ON LABEL IN FIGURE 3-3. HENDRICKSON ADVISES REPLACING ALL COMPONENTS
FOUND TO BE DAMAGED OR OUT OF SPECIFICATIONS. ALL MAJOR HENDRICKSON
COMPONENTS ARE HEAT TREATED AND TEMPERED. AIRTEK/SOFTEK COMPONENTS CANNOT
BE BENT, WELDED, HEATED, OR REPAIRED WITHOUT REDUCING THE STRENGTH OR LIFE OF
THE COMPONENT. FAILURE TO FOLLOW THESE GUIDELINES CAN CAUSE LOSS OF VEHICLE
CONTROL, POSSIBLE PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE AND WILL VOID
APPLICABLE WARRANTIES.
IF A VEHICLE EQUIPPED WITH A STEERTEK AXLE IS INVOLVED IN A CRASH, A THOROUGH
INSPECTION OF THE AXLE SHOULD BE PERFORMED NOTING THE CONDITION OF THE AXLE
BEAM, KINGPINS, AND KNUCKLE ASSEMBLIES. IF ANY COMPONENT APPEARS DAMAGED THE
AXLE SHOULD BE REPLACED. IN THE EVENT THE CRASH RESULTED IN EXCESSIVE SIDE LOAD
SUCH AS A BENT WHEEL, HUB, OR SPINDLE, IT IS STRONGLY RECOMMENDED TO REPLACE
THE COMPLETE AXLE ASSEMBLY, CONTACT HENDRICKSON TECHNICAL SERVICES WITH ANY
QUESTIONS. FAILURE TO REPLACE ANY DAMAGED COMPONENTS CAN CAUSE LOSS OF
VEHICLE CONTROL, POSSIBLE PERSONAL INJURY, DEATH, OR PROPERTY DAMAGE AND WILL
VOID APPLICABLE WARRANTIES.
17730-248
9
Important Safety Notice
1
APPENDIX
L
SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
PARTS CLEANING
SOLVENT CLEANERS CAN BE FLAMMABLE, POISONOUS AND CAUSE BURNS. TO HELP AVOID
SERIOUS PERSONAL INJURY, CAREFULLY FOLLOW THE MANUFACTURER’S PRODUCT
INSTRUCTIONS AND GUIDELINES AND THE FOLLOWING PROCEDURE:
52
1. WEAR PROPER EYE PROTECTION
2. WEAR CLOTHING THAT PROTECTS YOUR SKIN
3. WORK IN A WELL VENTILATED AREA
4. DO NOT USE GASOLINE, OR SOLVENTS THAT CONTAIN GASOLINE. GASOLINE CAN
EXPLODE
5. HOT SOLUTION TANKS OR ALKALINE SOLUTIONS MUST BE USED CORRECTLY. FOLLOW
THE MANUFACTURER’S RECOMMENDED INSTRUCTIONS AND GUIDELINES CAREFULLY
TO HELP PREVENT PERSONAL ACCIDENT OR INJURY
DO NOT USE HOT SOLUTION TANKS OR WATER AND ALKALINE SOLUTIONS TO CLEAN GROUND
OR POLISHED PARTS. DOING SO WILL CAUSE DAMAGE TO THE PARTS AND VOID WARRANTY.
Important Safety Notice
L
1
APPENDIX
10
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
SECTION 4
Special Tools
These shop made tools are designed to install and remove kingpin bushings. Bushing tools are made from cold rolled
steel or equivalent. Drawings are for reference only. Hendrickson does not supply these tools.
53
KINGPIN BUSHING TOOLS
ADJUSTABLE STRAIGHT FLUTE REAMER
17730-248
11
Special Tools
1
APPENDIX
L
SERVICE MANUAL
SECTION 5
Parts List
Blue Bird Vision Buses - 10K Capacity
54
Parts Lists
L
1
APPENDIX
12
17730-248
Front axle & suspension
AIRTEK® for Blue Bird Vision Buses - 10K Capacity
KEY NO. PART NO.
1
2
64075-002L
60850-001
59427-008
3
4
59935-004
59428-006
64742-001
5
6
7
8
9
10
11
12
13
14
15
16
17
18
58913-009L
59946-001
59423-002
60961-163
19a
19b
20
21
22
23
66805-001
60512-000
64488-002
24a
24b
25
26
66510-001
64316-000
64314-000
64159-000
27
28
29
60952-XXX
30
64905-004
31
58900-035
58900-033
58900-031
58900-055
58900-053
58900-051
32
33
34
58900-036
58900-034
58900-032
58900-056
58900-054
58900-052
60903-016
60904-002
60961-040
60961-009
17730-248
DESCRIPTION
NO.REQ.
KEY NO. PART NO.
Air Spring
2
Air Spring Bracket
2
HCV, Link Mount & Linkage Assembly
1
(Includes Key Nos. 3-11)
Height Control Valve
1
HCV Linkage (Replaces 59428-001)
1
Link Mount Service Kit
(Includes Key Nos. 5-6)
*5⁄16"-18 UNC Stud - 2.07"
1
*5⁄16"-18 UNC Stud - 2.44"
1
*5⁄16"-18 UNC Hex Nut
2
*5⁄16" Hardened Washer
2
5
* ⁄16"-18 UNC Locknut
2
*¼" Hardened Washer
2
*¼"-20 UNC Locknut
2
Shock Absorber (Replaces 58913-008)
2
**¾"-10 UNC Upper Shock Bolt
2
**¾"-10 UNC Lower Shock Bolt
2
**¾" Hardened Washer
8
**¾"-10 UNC Hex Locknut
4
Shock Spacer
2
Shock Bracket
2
Leaf Spring Assembly Service Kit
For vehicles built prior to 11/06
(Includes Key Nos. 19a, 24a, 25)
Leaf Spring Assembly
2
For vehicles built after 11/06
For vehicles built prior to 11/06
Front Hanger (Replaces 64488-000)
2
**M20 Hex Bolt - 170mm
2
**M20 Hardened Washer
4
**M20 Locknut
2
Rear Shackle Bracket
2
For vehicles built after 11/06
For vehicles built prior to 11/06
Rear Shackle Plate
4
Thrust Washer
4
Only for vehicles built prior to 11/06
**M20 Hex Bolt - 150mm
4
**M20 Hardened Washer
8
**M20 Locknut
4
Axle Assembly (Includes Key Nos. 30-55) 1
Contact Hendrickson Tech Serv. for Part No.
Axle & Kingpin Assembly
1
6.5", 8.5" Ride Height
LH Lower Steering Knuckle Assembly
1
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
RH Lower Steering Knuckle Assembly
1
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
LH Upper Steering Knuckle Assembly
1
RH Upper Steering Knuckle Assembly
1
Kingpin Bushing and Bearing Service Kit,
Axle Set
(Includes Kit Nos. 60961-009 & -039)
LH Kingpin Bushing w/Composite Thrust
Bearing Service Kit
(Includes Key Nos.35-38, 40-42, Loctite)
60961-039
35
36
37
59156-000
58937-000
58909-000
60961-043
60961-041
60961-042
38
39
40
Not Shown
41
42
Not Shown
43
44
59828-000
64256-000
60259-002
60259-001
58910-000
60236-001
60937-000
64246-000
66699-003
66699-001
45
60961-139
60961-137
60961-138
46
47
48
49
66645-001
66645-002
22962-007
17800-004
60961-069
50
51
52
53
60238-001
60240-000
59952-003
64722-003
60961-015
54
55
60508-000
59845-000
60961-051
60961-052
56
57
58
Not Shown
21867-044
21867-045
22962-001
17700-035
18831-021
59
64516-001
64516-002
60
Not Shown
13
64536-010
64536-060
64536-050
DESCRIPTION
NO.REQ.
RH Kingpin Bushing w/Roller Thrust
Bearing Service Kit
(Includes Key Nos.35-37, 39-42, Loctite)
Grease Cap Assembly
4
Retaining Ring
4
Kingpin Bushing
4
Thrust Bearing Service Kit, Axle Set
(Includes Kit Nos. 60961-041 & 60961-042)
LH Composite Thrust Bearing Service Kit
(Includes Key Nos. 38, 40-42, Loctite)
RH Roller Thrust Bearing Service Kit
(Includes Key Nos. 39-42, Loctite)
LH Composite Thrust Bearing
1
RH Roller Thrust Bearing
1
Kingpin Shim - 0.047"
2
Kingpin Shim - 0.005" (As needed for service)
Kingpin Seal
4
5⁄8"-11 UNC Socket Head Cap Screw
4
Loctite (Red) Compound Tube
1
ABS Sensor Sleeve
2
***Tie Rod Assembly, 10K, 5.36 Drop
1
(Includes Key Nos. 45-49)
200 Ackermann (Replaces 59948-005)
250 Ackermann (Replaces 59948-006)
*7⁄8" Castle Nut
2
***Tie Rod End Service Kit, Axle Set
(Replaces 60961-012)
(Includes Kit Nos. 60961-137 & -138)
***LH Tie Rod End Service Kit
(Replaces 60961-029)
(Includes Key Nos. 46, 48-49)
***RH Tie Rod End Service Kit
(Replaces 60961-030)
(Includes Key Nos. 47-49)
***LH Tie Rod End (Replaces 64004-001) 1
***RH Tie Rod End (Replaces 64004-002) 1
7⁄8" Flat Washer
2
Tie Rod Nut Cotter Pin
2
Stop Bolt Service Kit, One Side
(Includes Key Nos. 50-51)
½"-13 UNC Square Head Bolt
2
½"-13 UNC Hex Jam Nut
2
Top Axle Wrap
2
Bottom Axle Wrap
2
Top/Bottom Axle Wrap Liner Service Kit,
One Side (Includes Key Nos. 54-55)
Top Axle Wrap Liner
2
Bottom Axle Wrap Liner
2
Clamp Group Service Kit, One Side
(Includes Key Nos. 56-58)
6.5" Ride Height
8.5" Ride Height
¾"-16 UNF Hex bolt
8
6.5" Ride Height - 10.0"
8.5" Ride Height - 12.0"
¾" Flat Washer
8
¾"-16 UNF 2B Nylon Locknut
8
Dowel Pin, 8.5" Ride Height - 2.0"
2
Top Pad
LH
1
RH
1
Front Axle Spacer
LH 6.5" Ride Height
1
LH 8.5" Ride Height
1
RH 8.5" Ride Height
1
55
Parts Lists
1
APPENDIX
L
SERVICE MANUAL
Blue Bird Vision Buses - 8K/10K Capacity
9
10
11 12
45
11
56
9
49
13a
12
8a
45
10
2
4
11
1
7
11
48
4
49
17 16
4
7
50
17
14
18
4
1
17
13a
16
8a
14
4
4
3
3
5
17 18
14
43
16 17
43
4
17
14
41
6
16
18
17
41
17
5
5
4
6
48
2
5
30
29
25
24
23
26
21 32
31
34
25
30
24
19
29
28
30
26
22
44
20
31 32
34
39
40
26
37 38
42
46
46
47
35
24
44
27
30
47
37
38
39 40
26
24
42
25
46
46
36
47
47
33
25
51
45
For vehicles built
prior to 11/06
For 8K vehicles
built prior to 2/07
13b
8b
17
18
52
51
16
8b
17
17 18
14
Parts Lists
L
1
APPENDIX
14
15
15
14
17730-248
Front axle & suspension
SOFTEK® for Blue Bird Vision Buses - 8K/10K Capacity
KEY NO. PART NO.
1
2
3
4
5
6
7
58913-009L
59946-001
59423-002
60961-161
60961-162
8a
66623-001
66624-001
8b
9
10
11
12
13a
13b
14
15
66364-000
60511-000
64488-002
66510-001
64316-000
64314-000
64159-000
16
17
18
60952-XXX
19
64905-004
20
58900-035
58900-033
58900-031
58900-055
58900-053
58900-051
21
22
23
58900-036
58900-034
58900-032
58900-056
58900-054
58900-052
60903-016
60904-002
60961-040
60961-009
60961-039
24
25
26
59156-000
58937-000
58909-000
17730-248
DESCRIPTION
NO.REQ.
KEY NO. PART NO.
Shock Absorber (Replaces 58913-007)
2
**¾"-10 UNC Upper Shock Bolt
2
**¾"-10 UNC Lower Shock Bolt
2
**¾" Hardened Washer
8
**¾"-10 UNC Hex Locknut
4
Shock Spacer
2
Shock Bracket
2
Leaf Spring Assembly Service Kit
For vehicles built after11/06
(Includes Key Nos. 8a, 13a, 14)
8K
10K
Leaf Spring Assembly
2
For vehicles built after 11/06
8K
10K
For vehicles built prior to 11/06
8K
10K
Front Hanger (Replaces 64488-000)
2
**M20 Hex Bolt - 170mm
2
**M20 Hardened Washer
4
**M20 Locknut
2
Rear Shackle Bracket
2
For vehicles built after 11/06
For vehicles built prior to 11/06
Rear Shackle Plate
4
Thrust Washer
4
Only for vehicles built prior to 11/06
**M20 Hex Bolt - 150mm
4
**M20 Hardened Washer
8
**M20 Locknut
4
STEERTEK Axle Assembly
1
Contact Hendrickson Tech Serv. for Part No.
(Includes Key Nos. 19-44)
Axle & Kingpin Assembly
1
6.5", 8.5" Ride Height
LH Lower Steering Knuckle Assembly
1
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
RH Lower Steering Knuckle Assembly
1
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
LH Upper Steering Knuckle Assembly
1
RH Upper Steering Knuckle Assembly
1
Kingpin Bushing and Bearing Service Kit,
Axle Set
(Includes Kit Nos. 60961-009 & -039)
LH Kingpin Bushing w/Composite Thrust
Bearing Service Kit
(Includes Key Nos. 24-27, 29-31, Loctite)
RH Kingpin Bushing w/Roller Thrust
Bearing Service Kit
(Includes Key Nos. 24-26, 28-31, Loctite)
Grease Cap Assembly
4
Retaining Ring
4
Kingpin Bushing
4
60961-043
60961-041
60961-042
27
28
29
Not Shown
30
31
Not Shown
32
33
59828-000
64256-000
60259-002
60259-001
58910-000
60236-001
60937-000
64246-000
66699-003
66699-001
34
60961-139
60961-137
60961-138
35
36
37
38
66645-001
66645-002
22962-007
17800-004
60961-069
39
40
41
42
60238-001
60240-000
59952-003
64722-003
60961-015
43
44
60508-000
59845-000
60961-140
60961-141
45
46
47
Not Shown
48
49
50
64519-000
64080-000
51
64536-010
64536-060
64536-050
66164-000
52
66366-001
Not Shown
15
64804-110
64804-130
22962-001
17700-035
18831-021
64506-000
DESCRIPTION
NO.REQ.
Thrust Bearing Service Kit, Axle Set
(Includes Kit Nos. 60961-041& -042)
LH Composite Thrust Bearing Service Kit
(Includes Key Nos. 27, 29-31, Loctite)
RH Roller Thrust Bearing Service Kit
(Includes Key Nos. 28-31, Loctite)
LH Composite Thrust Bearing
RH Roller Thrust Bearing
Kingpin Shim - 0.047"
Kingpin Shim - 0.005" (As needed for service)
Kingpin Seal
5⁄8"-11 UNC Socket Head Cap Screw
Loctite (Red) Compound Tube
ABS Sensor Sleeve
***Tie Rod Assembly, 10K, 5.36 Drop
(Includes Key Nos. 34-38)
200 Ackermann (Replaces 59948-005)
250 Ackermann (Replaces 59948-006)
7
* ⁄8" Castle Nut
***Tie Rod End Service Kit, Axle Set
(Replaces 60961-012)
(Includes Kit Nos. 60961-137 & -138)
***LH Tie Rod End Service Kit
(Replaces 60961-029)
(Includes Key Nos. 35, 37-38)
***RH Tie Rod End Service Kit
(Replaces 60961-030)
(Includes Key Nos. 36-38)
***LH Tie Rod End (Replaces 64004-001)
***RH Tie Rod End (Replaces 64004-002)
7⁄8" Flat Washer
Tie Rod Nut Cotter Pin
Stop Bolt Service Kit, One Side
(Includes Key Nos. 39-40)
½"-13 UNC Square Head Bolt
½"-13 UNC Hex Jam Nut
Top Axle Wrap
Bottom Axle Wrap
Top/Bottom Axle Wrap Liner Service Kit,
One Side (Includes Key Nos. 43-44)
Top Axle Wrap Liner
Bottom Axle Wrap Liner
Clamp Group Service Kit, One side
(Includes Key Nos. 45-47)
6.5" Ride Height
8.5" Ride Height
¾"-16 UNF U-bolt
6.5" Ride Height - 11.0"
8.5" Ride Height - 13.0"
¾" Flat Washer
¾"-16 UNF 2B Nylon Locknut
Dowel Pin, 8.5" Ride Height - 2.0"
Top Pad/Axle Stop Assembly
(Includes Key Nos. 48-49)
Top Pad
Rubber Axle Stop
Front Axle Spacer
LH 6.5" Ride Height
LH 8.5" Ride Height
RH 8.5" Ride Height
Thrust Pad Washer
For 8K vehicles built prior to 2/07
Clamp Group Spacer
For 8K vehicles built prior to 2/07
1
1
2
57
4
4
1
2
1
2
1
1
2
2
2
2
2
2
2
2
4
8
8
1
2
2
1
1
1
2
4
Parts Lists
1
APPENDIX
L
SERVICE MANUAL
Blue Bird All American Buses
14.6K Capacity - Left Hand Drive Steertek Axle
58
Parts Lists
L
1
APPENDIX
16
17730-248
Front axle & suspension
AIRTEK® for Blue Bird All American Buses - 14.6K Capacity
KEY NO. PART NO.
1
2
3
4
5
6
66865-002L
66807-001
22962-014
17730-015
59013-000
7
8
9
60501-000
22962-028
49983-000
66825-001
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
59428-005
58913-011L
59946-006
65000-002
66805-001
64488-002
66510-001
64314-000
60952-XXX
32
64905-004
64905-007
33
58900-035
58900-033
58900-031
58900-055
58900-053
58900-051
34
35
36
58900-036
58900-034
58900-032
58900-056
58900-054
58900-052
60903-055
60904-002
60961-040
60961-009
60961-039
37
38
39
59156-000
58937-000
58909-000
17730-248
DESCRIPTION
NO.REQ.
KEY NO. PART NO.
Air Spring
2
Air Spring Bracket
2
½" Hardened Washer
2
½"-13 UNC Nylon Locknut
2
**¾" Hardened Washer
2
**¾"-10 UNC Nylon Locknut
2
Height Control Valve Assembly
2
(Includes Key Nos. 7-9)
Height Control Valve
2
¼" Hardened Washer
4
¼"-20 UNC Locknut
4
HCV Linkage Assembly
2
(Includes Key Nos. 10-14)
HCV Linkage
2
5
* ⁄16"-18 UNC Stud - 2.44"
4
5
* ⁄16"-18 UNC Hex Nut
4
*5⁄16" Hardened Washer
4
5
* ⁄16"-18 UNC Locknut
4
Shock Absorber
2
**¾"-10 UNC Upper Shock Bolt
2
**¾"-10 UNC Lower Shock Bolt
2
**¾" Hardened Washer
6
**¾"-10 UNC Hex Locknut
4
Shock Spacer
2
Shock Bracket
2
Leaf Spring Assembly
2
Front Hanger
2
**M20 Hex Bolt - 170mm
2
**M20 Hardened Washer
4
**M20 Locknut
2
Rear Shackle Bracket
2
Rear Shackle Plate
4
**M20 Hex Bolt - 150mm
4
**M20 Hardened Washer
8
**M20 Locknut
4
Axle Assembly (Includes Key Nos. 32-57) 1
Contact Hendrickson Tech Serv. for Part No.
Axle & Kingpin Assembly
1
6.8", 7.8", 8.8" and 9.8" Ride Height
13.2K
14.6K
LH Lower Steering Knuckle Assembly
1
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
RH Lower Steering Knuckle Assembly
1
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
LH Upper Steering Knuckle Assembly
1
RH Upper Steering Knuckle Assembly
1
Kingpin Bushing and Bearing Service Kit,
Axle Set
(Includes Kit Nos. 60961-009 & -039)
LH Kingpin Bushing w/Composite Thrust
Bearing Service Kit
(Includes Key Nos.37-40, 42-44, Loctite)
RH Kingpin Bushing w/Roller Thrust
Bearing Service Kit
(Includes Key Nos.37-39, 41-44, Loctite)
Grease Cap Assembly
4
Retaining Ring
4
Kingpin Bushing
4
60961-043
60961-041
60961-042
40
41
42
Not Shown
43
44
Not Shown
45
46
59828-000
64256-000
60259-002
60259-001
58910-000
60236-001
60937-000
64246-000
64006-002
64006-003
47
60961-011
60961-027
60961-028
48
49
50
51
64002-001
64002-002
22962-007
17800-004
60961-069
52
53
54
55
60238-001
60240-000
59952-026
64722-003
60961-015
56
57
60508-000
59845-000
60961-051
60961-146
60961-052
60961-147
58
59
60
61
21867-044
21867-027
21867-045
21867-035
22962-001
17700-035
18831-022
18831-021
18831-023
62
66814-001
66814-002
63
64536-025
64536-050
64536-075
17
DESCRIPTION
NO.REQ.
Thrust Bearing Service Kit, Axle Set
(Includes Kit Nos. 60961-041 & 60961-042)
LH Composite Thrust Bearing Service Kit
(Includes Key Nos. 40, 42-44, Loctite)
RH Roller Thrust Bearing Service Kit
(Includes Key Nos. 41-44, Loctite)
LH Composite Thrust Bearing
1
RH Roller Thrust Bearing
1
Kingpin Shim - 0.047"
2
Kingpin Shim - 0.005" (As needed for service)
Kingpin Seal
4
5⁄8"-11 UNC Socket Head Cap Screw
4
Loctite (Red) Compound Tube
1
ABS Sensor Sleeve
2
***Tie Rod Assembly, 14.6K, 5.36 Drop
1
(Includes Key Nos. 47-51)
150/200 Ackermann
250 Ackermann
7
* ⁄8" Castle Nut
2
Tie Rod End Service Kit, Axle Set
(Includes Kit Nos. 60961-027 & -028)
LH Tie Rod End Service Kit
(Includes Key Nos. 48, 50-51)
RH Tie Rod End Service Kit
(Includes Key Nos. 49-51)
LH Tie Rod End
1
RH Tie Rod End
1
7⁄8" Flat Washer
2
Tie Rod Nut Cotter Pin
2
Stop Bolt Service Kit, One Side
(Includes Key Nos. 52-53)
½"-13 UNC Square Head Bolt
2
½"-13 UNC Hex Jam Nut
2
Top Axle Wrap
2
Bottom Axle Wrap
2
Top/Bottom Axle Wrap Liner Service Kit,
One Side (Includes Key Nos. 56-57)
Top Axle Wrap Liner
2
Bottom Axle Wrap Liner
2
Clamp Group Service Kit, One side
(Includes Key Nos. 58-60)
6.8" Ride Height
7.8" Ride Height
8.8" Ride Height
9.8" Ride Height
¾"-16 UNF Hex bolt
8
6.8" Ride Height - 10.0"
7.8" Ride Height - 11.0"
8.8" Ride Height - 12.0"
9.8" Ride Height - 13.0"
¾" Flat Washer
8
¾"-16 UNF 2B Nylon Locknut
8
Dowel Pin
6.8" Ride Height
None Req.
7.8" Ride Height - 1.13"
2
8.8" Ride Height - 2.0"
2
9.8" Ride Height - 3.0"
2
Top Pad
LH
1
RH
1
LH/RH Front Axle Spacer
6.8" Ride Height
None Req.
7.8" Ride Height
2
8.8" Ride Height
2
9.8" Ride Height
2
59
Parts Lists
1
APPENDIX
L
SERVICE MANUAL
Blue Bird All American Buses
13.2K/14.6K Capacity - Left Hand Drive Steertek Axle
60
Parts Lists
L
1
APPENDIX
18
17730-248
Front axle & suspension
SOFTEK® for Blue Bird All American Buses - 13.2K/14.6K Capacity
KEY NO. PART NO.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
58913-010L
59946-001
65000-002
66625-001
66626-001
64488-002
66510-001
64314-000
60952-XXX
18
64905-002
64905-005
19
58900-035
58900-033
58900-031
58900-055
58900-053
58900-051
20
21
22
58900-036
58900-034
58900-032
58900-056
58900-054
58900-052
60903-055
60904-002
60961-040
60961-009
60961-039
23
24
25
59156-000
58937-000
58909-000
60961-043
60961-041
60961-042
26
27
28
Not Shown
29
30
Not Shown
31
59828-000
64256-000
60259-002
60259-001
58910-000
60236-001
60937-000
64246-000
17730-248
DESCRIPTION
NO.REQ.
KEY NO. PART NO.
32
Shock Absorber
2
**¾"-10 UNC Upper Shock Bolt
2
**¾"-10 UNC Lower Shock Bolt
2
**¾" Hardened Washer
6
**¾"-10 UNC Hex Locknut
4
Shock Spacer
2
Shock Bracket
2
Leaf Spring Assembly
2
13.2K
14.6K
Front Hanger
2
**M20 Hex Bolt - 170mm
2
**M20 Hardened Washer
4
**M20 Locknut
2
Rear Shackle Bracket
2
Rear Shackle Plate
4
**M20 Hex Bolt - 150mm
4
**M20 Hardened Washer
8
**M20 Locknut
4
STEERTEK Axle Assembly
1
Contact Hendrickson Tech Serv. for Part No.
(Includes Key Nos. 18-43)
Axle & Kingpin Assembly
1
6.8", 7.8", 8.8" and 9.8" Ride Height
13.2K
14.6K
LH Lower Steering Knuckle Assembly
1
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
RH Lower Steering Knuckle Assembly
1
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
LH Upper Steering Knuckle Assembly
1
RH Upper Steering Knuckle Assembly
1
Kingpin Bushing and Bearing Service Kit,
Axle Set
(Includes Kit Nos. 60961-009 & -039)
LH Kingpin Bushing w/Composite Thrust
Bearing Service Kit
(Includes Key Nos. 23-26, 28-30, Loctite)
RH Kingpin Bushing w/Roller Thrust
Bearing Service Kit
(Includes Key Nos. 23-25, 27-30, Loctite)
Grease Cap Assembly
4
Retaining Ring
4
Kingpin Bushing
4
Thrust Bearing Service Kit, Axle Set
(Includes Kit Nos. 60961-041& -042)
LH Composite Thrust Bearing Service Kit
(Includes Key Nos. 26, 28-30, Loctite)
RH Roller Thrust Bearing Service Kit
(Includes Key Nos. 27-30, Loctite)
LH Composite Thrust Bearing
1
RH Roller Thrust Bearing
1
Kingpin Shim - 0.047"
2
Kingpin Shim - 0.005" (As needed for service)
Kingpin Seal
4
5⁄8"-11 UNC Socket Head Cap Screw
4
Loctite (Red) Compound Tube
1
ABS Sensor Sleeve
2
64006-002
64006-003
33
60961-011
60961-027
60961-028
34
35
36
37
64002-001
64002-002
22962-007
17800-004
60961-069
38
39
40
41
60238-001
60240-000
59952-026
64722-003
60961-015
42
43
60508-000
59845-000
60961-142
60961-143
60961-144
60961-145
44
45
46
47
64804-120
64804-130
64804-140
64804-150
22962-001
17700-035
18831-022
18831-021
18831-023
66806-001
48
49
50
66666-000
64080-000
64536-010
64536-035
64536-060
64536-085
51
64536-025
64536-050
64536-075
19
DESCRIPTION
NO.REQ.
Tie Rod Assembly, 14.6K, 5.36 Drop
1
(Includes Key Nos. 33-37)
150/200 Ackermann
250 Ackermann
*7⁄8" Castle Nut
2
Tie Rod End Service Kit, Axle Set
(Includes Kit Nos. 60961-027 & -028)
LH Tie Rod End Service Kit
(Includes Key Nos. 34, 36-37)
RH Tie Rod End Service Kit
(Includes Key Nos. 35-37)
LH Tie Rod End
1
RH Tie Rod End
1
7⁄8" Flat Washer
2
Tie Rod Nut Cotter Pin
2
Stop Bolt Service Kit, One Side
(Includes Key Nos. 38-39)
½"-13 UNC Square Head Bolt
2
½"-13 UNC Hex Jam Nut
2
Top Axle Wrap
2
Bottom Axle Wrap
2
Top/Bottom Axle Wrap Liner Service Kit,
One Side (Includes Key Nos. 42-43)
Top Axle Wrap Liner
2
Bottom Axle Wrap Liner
2
Clamp Group Service Kit, One side
(Includes Key Nos. 44-46)
6.8" Ride Height
7.8" Ride Height
8.8" Ride Height
9.8" Ride Height
¾"-16 UNF U-bolt
4
6.8" Ride Height - 12.0"
7.8" Ride Height - 13.0"
8.8" Ride Height - 14.0"
9.8" Ride Height - 15.0"
¾" Flat Washer
8
¾"-16 UNF 2B Nylon Locknut
8
Dowel Pin
6.8" Ride Height
None Req.
7.8" Ride Height - 1.13"
2
8.8" Ride Height - 2.0"
2
9.8" Ride Height - 3.0"
2
Top Pad/Axle Stop Assembly
(Includes Key Nos. 48-49)
Top Pad
2
Rubber Axle Stop
2
LH Front Axle Spacer
1
6.8" Ride Height
7.8" Ride Height
8.8" Ride Height
9.8" Ride Height
RH Front Axle Spacer
1
6.8" Ride Height
None Req.
7.8" Ride Height
8.8" Ride Height
9.8" Ride Height
61
Parts Lists
1
APPENDIX
L
SERVICE MANUAL
Right Hand Drive for Blue Bird All American Buses
13.2K/14.6K Capacity
62
KEY NO. PART NO.
67905-402
67905-404
67905-405
67905-407
1
58900-035
58900-033
58900-031
58900-055
58900-053
58900-051
2
3
4
58900-036
58900-034
58900-032
58900-056
58900-054
58900-052
60904-001
70903-001
60961-040
60961-009
60961-039
5
6
7
59156-000
58937-000
58909-000
60961-043
60961-041
DESCRIPTION
NO.REQ.
STEERTEK Axle Assembly
(Includes Key Nos. 1-25)
SOFTEK Standard Drop - 13.2K
AIRTEK Deep Drop - 13.2K
SOFTEK Standard Drop - 14.6K
AIRTEK Deep Drop - 14.6K
LH Lower Steering Knuckle Assembly
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
RH Lower Steering Knuckle Assembly
150 Ackermann Air Brake
200 Ackermann Air Brake
250 Ackermann Air Brake
150 Ackermann Hydraulic Brake
200 Ackermann Hydraulic Brake
250 Ackermann Hydraulic Brake
LH Upper Steering Knuckle Assembly
RH Upper Steering Knuckle Assembly
Kingpin Bushing and Bearing Service Kit,
Axle Set
(Includes Kit Nos. 60961-009 & -039)
RH Kingpin Bushing w/Composite Thrust
Bearing Service Kit
(Includes Key Nos. 5-8, 10-12, Loctite)
LH Kingpin Bushing w/Roller Thrust
Bearing Service Kit
(Includes Key Nos. 5-7, 9-12, Loctite)
Grease Cap Assembly
Retaining Ring
Kingpin Bushing
Thrust Bearing Service Kit, Axle Set
(Includes Kit Nos. 60961-041& -042)
RH Composite Thrust Bearing Service Kit
(Includes Key Nos. 8, 10-12, Loctite)
KEY NO. PART NO.
60961-042
1
8
9
10
Not Shown
1
11
12
Not Shown
13
14
59828-000
64256-000
60259-002
60259-001
58910-000
60236-001
60937-000
64246-000
60239-005
60239-001
1
15
60961-010
60961-025
60961-026
1
1
4
4
4
16
17
18
19
64000-001
64000-002
22962-007
17800-004
60961-069
20
21
22
60238-001
60240-000
59952-026
59952-031
64722-003
60961-015
23
24
25
60508-000
59845-000
DESCRIPTION
NO.REQ.
LH Roller Thrust Bearing Service Kit
(Includes Key Nos. 9-12, Loctite)
RH Composite Thrust Bearing
LH Roller Thrust Bearing
Kingpin Shim - 0.047"
Kingpin Shim - 0.005" (As needed for service)
Kingpin Seal
5⁄8"-11 UNC Socket Head Cap Screw
Loctite (Red) Compound Tube
ABS Sensor Sleeve
Tie Rod Assembly, 13.2K
(Includes Key Nos. 15-19)
150/200 Ackermann
250 Ackermann
7
* ⁄8" Castle Nut
Tie Rod End Service Kit, Axle Set
(Includes Kit Nos. 60961-025 & -026)
LH Tie Rod End Service Kit
(Includes Key Nos. 16, 18-19)
RH Tie Rod End Service Kit
(Includes Key Nos. 17-19)
LH Tie Rod End
RH Tie Rod End
7⁄8" Flat Washer
Tie Rod Nut Cotter Pin
Stop Bolt Service Kit, One Side
(Includes Nos. 20-21)
½"-13 UNC Square Head Bolt
½"-13 UNC Hex Jam Nut
Top Axle Wrap - 13.2K
Top Axle Wrap - 14.6K
Bottom Axle Wrap
Top/Bottom Axle Wrap Liner Service Kit,
One Side (Includes Nos. 24-25)
Top Axle Wrap Liner
Bottom Axle Wrap Liner
1
1
2
4
4
1
2
1
2
1
1
2
2
2
2
2
2
2
2
NOTE: * Item included in assembly only, part not sold separately.
** Not supplied by Hendrickson, used for reference only. Refer to OEM (vehicle manufacturer) for more information. Hendrickson is not responsible
for components supplied by vehicle manufacturer. For assistance with maintenance and rebuild instructions on these components see vehicle
manufacturer.
*** Hendrickson supplies different tie rod assemblies and each type may take a different replacement tie rod end kit to service. Prior to ordering, find
the part number on the tie rod tube, reference Hendrickson Publication No. SEU-0223 or contact Hendrickson Sales Engineering 630.910.2800
for corresponding kit numbers.
NOTE: Quantities of service kit components may vary from amount shown in lists.
Parts Lists
L
1
APPENDIX
20
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
SECTION 6
On Highway and On Roadway
Recommended Towing Procedure
Hendrickson recommends that a vehicle equipped with a STEERTEK axle be towed by the
following methods (listed in order of preference) for ON HIGHWAY or ON ROADWAY
applications.
63
1. Wheel lift method, the ideal towing procedure
2. Towing the vehicle from the rear method
3. Conventional axle fork method
Please read, understand and comply with any additional towing instructions and safety precautions that may be provided by the vehicle manufacturer.
Hendrickson will not be responsible for any damage to the axle, suspension or other vehicle
components resulting from any towing method or fixture not authorized by Hendrickson.
Please contact Hendrickson Tech Services at 630.910.2800 or send email to:
techservices@hendrickson-intl.com with any questions regarding proper towing procedures
for vehicles equipped with a STEERTEK axle.
WHEEL LIFT METHOD—IDEAL
This method provides the greatest ease for towing the vehicle. Lifting at the tires helps
reduce the risk of possible damage to the axle, suspension, and engine components during towing operations, see Figure 6-1.
FIGURE 6-1 Wheel lift method
TOWING VEHICLE FROM THE REAR METHOD
This method is preferred when the proper equipment is not available to perform the wheel
lift method and is necessary for wreckers not equipped with an under lift system.
17730-248
21
Towing Procedure
1
APPENDIX
L
SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
AXLE FORK LIFT METHOD
This is an alternative method for towing the vehicle, but requires standard 5" forks, (see
Figures 6-2 and 6-3) and designated lift points inside the axle clamp groups. The following procedure must be used:
64
■
Place a spacer on the boom, to provide adequate clearance between the oil pan and
the boom if necessary. Lift the vehicle in order to place spacer under tires. This will provide sufficient room under the axle to locate forks in the proper position.
■
Install the fork in the boom properly.
■
Position the tow forks directly under the axle, inside the axle clamp groups as shown
in Figure 6-2.
FIGURES 6-2 AND 6-3
PROPER TOW FORK LOCATION ON INSIDE CLAMP GROUP ON THE STEERTEK AXLE
■
Prior to lifting the vehicle, ensure that the bottom axle plate is flat in the tow fork to
minimize any gap between the bottom axle plate and the tow fork, see Figure 6-4 and
6-5. It may be necessary to deflate the air in the steer axle suspension, and/or release
the tractor brakes. Deflate the steer axle air springs by disconnecting the height control
valve linkage and lowering the height control valve linkage arm. This will exhaust the
air pressure in the steer axle air springs.
FIGURE 6-4 WITHOUT GAP
NOTE
Towing Procedure
L
1
APPENDIX
FIGURE 6-5 WITH GAP
When lifting a vehicle with an under lift boom, care must be taken not to damage the
engine’s oil pan. Vehicles equipped with a front fairing may require removal of the front
fairing prior to towing to prevent component damage.
■
Lift vehicle and secure the vehicle to the boom.
■
Install safety straps, it is preferred to use nylon safety straps. Chains have a tendency
to bind and may cause damage to the axle.
22
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
OFF ROADWAY TOWING METHOD
WHEN A VEHICLE IS DISABLED AND EQUIPPED WITH A STEERTEK AXLE, CARE MUST BE
TAKEN TO ENSURE THERE IS NO DAMAGE TO THE SUSPENSION OR AXLE WHEN TOWING THE
VEHICLE. THE USE OF A TOW STRAP IS NECESSARY TO TOW A DISABLED VEHICLE INTO A
REPAIR FACILITY PARKING LOT INTO THE SHOP BAY. THE TOW STRAPS SHOULD BE
CONNECTED TO THE TOW HOOKS PROVIDED BY THE VEHICLE MANUFACTURER AT THE
FRONT OF THE BUMPER. IF THE USE OF TOW HOOKS IS NOT AN OPTION THEN A TOW STRAP
MAY BE WRAPPED AROUND THE FRONT AXLE, (SEE FIGURE 6-6) IN A MANNER THAT IS
ACCEPTABLE FOR TOWING THE VEHICLE INTO THE SHOP. DO NOT USE A TOW CHAIN
AROUND THE FRONT AXLE TO TOW THE VEHICLE, DOING SO WILL DAMAGE THE AXLE AND
VOID WARRANTY, (SEE FIGURE 6-7).
65
THE FOLLOWING METHODS ARE NOT RECOMMENDED FOR:
ON HIGHWAY OR ON ROADWAY TOWING
FIGURE 6-6
NYLON STRAPS ARE
ACCEPTABLE FOR
OFF ROADWAY TOWING
FIGURE 6-7
CHAINS ARE NOT
ACCEPTABLE FOR
OFF ROADWAY TOWING
17730-248
23
Towing Procedure
1
APPENDIX
L
SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
SECTION 7
Preventive Maintenance
Following appropriate inspection procedure is important to help ensure the proper maintenance and operation of the AIRTEK®/SOFTEK® suspension system and component parts
function to their highest efficiency.
HENDRICKSON RECOMMENDED PREVENTIVE MAINTENANCE INTERVALS
■ The first 1,000 miles
66
■
On-highway – every 25,000 miles (40,000 km) or 6 months, whichever comes first
COMPONENT INSPECTION
Air spring — Look for chaffing or any signs of spring or component damage.
Clamp group — Check torque on clamp group mounting hardware. Refer to
Torque
Specifications in the appendix of this publication.
■ Fasteners — Look for any loose or damaged fasteners on the entire suspension. Make
sure all fasteners are tightened to the specified torque. Refer to
Torque Specifications
in the appendix. Use a calibrated torque wrench to check torque in a tightening direction. As soon as the fastener starts to move, record the torque. Correct the torque if
necessary. Replace any worn or damaged fasteners.
■ Front hangers and shackle brackets — Check for cracks or loose mounting hardware.
Replace if necessary, see the Component Replacement Section of this publication for
replacement procedure.
■ Operation — All steering components must move freely through the full range of motion
from axle stop to axle stop.
■ Shock absorber — Look for any signs of dents or leakage, misting is not considered a
leak. See Shock Absorber Inspection in this section.
■ Steel leaf spring and wrap leaf assembly — Look for cracks. Check the front and rear
bushings for any wear or deterioration. Replace spring assembly if any of the previous
conditions are observed. See the Component Replacement Section of this publication for
replacement procedure.
■ STEERTEK Axle — The axle should be free of any nicks or gouges. Inspect for any
cracks or dents on axle.
■ Steering pivot points — Check for looseness at all pivot points. Inspect and lubricate all
pivot points. Refer to the Trouble Shooting Guide Section in the Appendix of this publication.
■ Thrust washers (If equipped) — Look for any signs of excessive wear to the thrust washers, shackles and shackle bracket. See Thrust Washer Inspection detailed in this section.
■ Tire wear — Inspect tires for wear patterns that may indicate suspension damage or
misalignment. See Tire Inspection in this section.
■ Top and bottom axle wrap liners — Look for any cracking or broken pieces on liner in
load bearing areas. See Axle Wrap Liner Inspection in this section.
■ Top pad (AIRTEK) — Check for cracks or damage. Replace if necessary, see the
Component Replacement Section of this publication for replacement procedure.
■ Top pad and bump stop (SOFTEK) — Check for cracks and/or missing rubber bump
stops. Replace if necessary, see the Component Replacement Section of this publication
for replacement procedure.
■ Wear and damage — Inspect all parts of suspension for wear and damage. Look for
bent or cracked parts. Replace all worn or damaged parts.
See vehicle manufacturer’s applicable publications for other preventative maintenance
requirements.
■
■
Preventive Maintenance
L
1
APPENDIX
24
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
LUBRICATION INTERVALS
For vehicles equipped with the STEERTEK axle, regular lubrication intervals should be
followed to help prevent premature wear to the kingpin bushings and tie rod ends, see lubrication chart below.
NOTE
The recommended service lubrication interval is a guideline, the vehicle may require
increased lubrication interval depending on severity of operation.
67
STEERTEK GREASING AND LUBRICATION SPECIFICATIONS
Component
Kinpin Bushings
Tie Rod Ends
Greasing Interval
Grease
NLGI
Grade
Outside Temperature
Maximum of
25,000 miles
(40,225 kilometers)
or 90 days, whichever
comes first.
Multipurpose
Grease
2
Refer to the lubricant
manufacturer’s specifications
for the temperature service
limits applicable to your area.
See Vehicle Manufacturer
Drag Link
NOTE: Lubrication greases acceptable for use on the STEERTEK axle will carry a designation of
NLGI #2 EP and rated GC-LB or equivalent.
KINGPIN LUBRICATION
On the Hendrickson STEERTEK front axle the kingpin grease fittings are located on the top
and bottom of the kingpin grease caps.
1. Place the vehicle on a level floor.
2. Prior to greasing the kingpins on the vehicle, the suspension must be in a loaded
condition.
3. Clean off all the grease fittings and grease gun tip with a clean shop towel prior to
lubrication.
4. Lubricate the kingpins through the grease fittings on the top and bottom of the steering
knuckle, see Lubrication Specification Matrix above.
5. Force the required lubricant into the upper and lower kingpin grease fittings, until new
lubricant flows from the upper axle beam and knuckle and the thrust bearing purge
location, see Figures 7-1 and 7-2.
NOTE
Greasing at the lower zerk should purge grease from the thrust bearing shell. Both sides
purge in the same area. The left side of the axle has a composite style thrust bearing, see
Figure 7-1 and the right side of the axle has a steel roller thrust bearing, see Figure 7-2,
for right hand drive axle configuration the thrust bearings will be the opposite.
FIGURE 7-1
17730-248
FIGURE 7-2
25
Preventive Maintenance
1
APPENDIX
L
SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
TIE ROD END LUBRICATION
LUBRICATION PROCEDURE
1. Turn the vehicle wheels straight ahead.
2. Wipe the zerk fitting and grease gun tip with clean shop towels.
3. Wipe the seal/boot clean with shop towels.
4. Attach a grease gun to the zerk fitting. Either a hand or pneumatic grease gun is acceptable. If air operated grease gun is used, system air pressure should not exceed 150
psi (1035 kPa).
68
EXCEEDING THE MAXIMUM AIR PRESSURE TO THE ZERK FITTING CAN CAUSE DAMAGE TO THE
DUST BOOT AND COMPONENT FAILURE.
5. Dirt, water, and discolored old grease should flow from the relief vents or purge holes
near the boot crimp or bellows area, see Figure 7-3. Continue to purge grease until
fresh grease flows from the purge area.
FIGURE 7-3
6. If the tie rod end is designed for lube service and it will not accept grease proceed as
follows:
a. Remove the zerk fitting
b. Inspect the threaded zerk fitting hole in the tie rod end and remove any obstructions
c. Install a new zerk fitting
d. Continue the lubrication procedure
e. If the tie rod end will not accept grease following this procedure it will be necessary to replace the tie rod end, (see Tie Rod End replacement in the Component
Replacement Section of this publication)
7. Apply grease until all the old grease is purged from the boot and fresh grease is coming out.
Preventive Maintenance
L
1
APPENDIX
26
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
TIE ROD END INSPECTION
INSPECTION PROCEDURE
Before beginning this inspection procedure, the entire system must be unloaded (i.e., the
front end of the vehicle must be raised and supported with safety stands).
DO NOT GREASE THE TIE ROD ASSEMBLY BEFORE PERFORMING THE INSPECTION. DOING SO
CAN INHIBIT EFFORTS TO DETERMINE ACTUAL WEAR.
69
REPLACE THE ENTIRE TIE ROD END IF THE BOOT IS TORN OR MISSING, FAILURE TO DO SO
CAN CAUSE PREMATURE WEAR OF THE TIE ROD END.
1. Block rear wheels of vehicle. Using the bottom of the axle beam or the frame rails, raise
the front end off the ground and support with stands.
2. With the engine off, turn the wheels from full left to full right and then return to the
straight-ahead position.
3. Check that the boots are in place and completely installed over the tie rod ends.
4. Check for cracking or tears in the boots. Also check the boot seals for damage. Replace
the entire tie rod end if the boot is damaged.
THE CORRECT COTTER PIN MUST BE INSTALLED THROUGH THE TIE ROD END WITH THE
CASTLE NUT TIGHTENED TO THE PROPER TORQUE SPECIFICATION IN ORDER TO SECURELY
ATTACH THE TIE ROD. LOSS OF THE COTTER PIN CAN CAUSE THE TIE ROD END NUT TO
BECOME LOOSE AND ADVERSELY AFFECT VEHICLE STEERING AND POSSIBLY RESULT IN TOTAL
LOSS OF STEERING CONTROL.
5. Check that the tie rod end nut is installed and secured with a cotter pin. If the cotter pin
is missing, check the nut torque specification and then install a new cotter pin. Always
tighten the castle nut to specified torque when setting the cotter pin. Do not back off the
nut to insert cotter pin.
FIGURE 7-4
6. Check that the tie rod end is
threaded correctly into the
cross tube and is engaged
deeper than the end of the
cross tube slot. The tie rod
end must be visible the entire
length of the cross tube slot,
see Figure 7-4.
7. Check that zerk fittings are
installed. Replace a damaged
zerk fitting with a new one.
DO NOT USE THE FOLLOWING ITEMS OR METHODS TO CHECK FOR MOVEMENT OF THE TIE
ROD ASSEMBLY. DAMAGE TO COMPONENTS CAN RESULT IF:
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■
A CROW BAR, PICKLE FORK OR 2 x 4 ARE USED.
■
ANYTHING OTHER THAN HANDS ARE USED TO GRASP THE CROSS TUBE ASSEMBLY (CAN
RESULT IN DAMAGE TO THE CROSS TUBE).
■
EXCESSIVE PRESSURE OR FORCE IS APPLIED TO THE TIE ROD ENDS OR THE JOINTS OF
THE ASSEMBLY.
27
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8. By hand or using a pipe wrench, with jaw protectors to avoid gouging the cross tube,
rotate the cross tube toward the front of the vehicle and then toward the rear. After rotating, center the cross tube. If the cross tube will not rotate in either direction, replace both
tie rod ends, see Figure 7-5.
FIGURE 7-5
70
FIGURE 7-6
9. Position yourself directly below the tie
rod end. Using both hands, grab the
assembly end as close to the tie rod end
as possible (no more than 6" or
152.4mm). Apply hand pressure with
reasonable human effort vertically up
and down in a push-pull motion several
times (using approx. 50-100 lbs. of
force). Check for any movement or
looseness at both tie rod end locations,
see Figure 7-6.
FIGURE 7-7
10. If there is any movement in the tie rod
assembly, install a magnetic based dial
indicator on the Ackermann arm, see
Figure 7-7.
11. Set the dial indicator to zero.
12. Apply hand pressure with reasonable
human effort vertically up and down in a
push-pull motion several times (using
approx. 50-100 lbs. of force). Observe
the reading on the dial indicator.
13. If the reading is more than 0.060",
replace both tie rod ends at the next service interval.
14. If a tie rod end exhibits 0.125" of movement by hand, the vehicle should be
removed immediately from use and the
tie rod end be replaced.
NOTE
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According to the Commercial Vehicle Safety Alliance (CVSA), the vehicle “out of service”
criteria is: Any motion other than rotational between any linkage member and its
attachment point of more than 1⁄8" (3mm) measured with hand pressure only.
(393.209(d)), (published in the North American Standard Out-of-Service Criteria
Handbook, April 1, 2006.)
28
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AIRTEK®• SOFTEK® for Blue Bird Buses
CLAMP GROUP RE-TORQUE INTERVAL
1. Clamp group locknuts must be torque to specification at preparation for delivery.
2. Clamp group locknuts must be re-torqued at 1,000 miles.
3. Thereafter follow the 6 month/ 25,000 mile inspection and annual re-torque interval.
4. Ensure that the clamp group is properly aligned and the hex bolts/U-bolts are seated in
the top pad, and the bottom axle wrap is centered on the top axle wrap, see Figure 7-8.
71
FIGURE 7-8
5. Check for the signs of component or bolt movement.
6. If signs of movement are present, disassemble the clamp group fasteners, check for
component wear or damage and replace as necessary, then install new clamp group
fasteners and repeat steps 1 through 5.
FIGURE 7-9
7. Tighten the clamp group locknuts evenly in 50 foot pounds increments
to 285-305 foot pounds torque in the proper pattern to achieve uniform bolt tension, see Figure 7-9.
TIRE INSPECTION
The leading causes of tire wear are the following, in order of importance:
1. Tire Pressure
2. Toe Setting
3. Thrust Angle
4. Camber
The following tire Inspection guidelines are based upon TMC (Technology & Maintenance
Council) recommended practices. Any issues regarding irregular tire wear where
Hendrickson is asked for assistance, will require tire and alignment maintenance records,
reference TMC’s literature numbers RP219A, RP230, or RP 642.
Tire wear is normally the best indicator of vehicle alignment condition. If tires are wearing
too rapidly or irregularly, alignment corrections may be needed. The tire wear patterns
described below can help isolate specific alignment problems.
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The most common conditions of concern are:
72
■
Overall Fast Wear (Miles per 32nd)
■
Feather Wear
■
Cupping
■
Diagonal Wear
■
Rapid Shoulder Wear (One Shoulder Only)
■
One-Sided Wear
FIGURE 7-10
Overall Fast Wear — Fast wear can be described as exhibiting a good, but accelerated
wear pattern. It is typically caused by operating conditions, such as mountainous terrain,
frequency and severity of turning, abrasive road surfaces in combination with vehicle configurations and their attributes-such as power steering, heavy axle loads, high wheel cuts,
setback axles, short wheel base tractors, long wheel base straight trucks. To correct this
problem, consult with vehicle and tire manufacturers when specifying equipment or replacing tires. For more information, see TMC RP 219A publication, page 11. For information on
how to accurately measure and record tire rates, see TMC RP 230 publication.
FIGURE 7-11
Feather wear — Tread ribs or blocks worn so that one side is higher than the other resulting in step-offs across the tread face. Generally, ribs or blocks exhibit this wear. To spot this
problem, do the following:
With one hand flat on the tread of the tire and a firm down pressure, slide your hand across
the tread of the tire. In one direction, the tire will feel smooth and in the opposite direction
there will be a sharp edge to the tread. Typical causes of feather wear include: excessive
side force scrubbing, resulting from conditions of misalignment such as excessive toe, drive
axle misalignment, worn, missing or damaged suspension components, bent tie rods or
other chassis misalignment.
To correct this problem, tires can be rotated to another axle for maximum utilization of
remaining tread. Additionally, diagnose the vehicle itself and correct misalignment condition as required. If steer tire feathers are in opposite directions, an improper toe condition is
most likely the cause. For more information, see TMC RP 219A publication, page 5.
If feather wear on both steer tires is in the same direction, drive axle or other chassis
misalignment is indicated. If one steer tire shows feather wear and the other steer tire has
normal wear, a combination of toe and drive axle or chassis misalignment is indicated.
FIGURE 7-12
Cupping — Localized, dished out areas of fast wear creating a scalloped
appearance around the tire. Cupping, which appears around the tire on
the shoulder ribs, may also progress to adjoining ribs, see TMC RP 219A
publication, page 7.
Cupping is usually a result of moderate-to-severe imbalance, improper
rim/wheel mounting, excessive wheel end play or other assembly nonuniformity. It can also be due to lack of shock absorber control on some
suspension types.
To solve cupping problems:
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Tires – Correct mismount or balance problem. If ride complaints arise,
steer tires may be rotated to drive or trailer axle.
■
Vehicle – Diagnose component imbalance condition, i.e., wheel, rim,
hub, brake, drum. Correct as necessary.
30
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AIRTEK®• SOFTEK® for Blue Bird Buses
FIGURE 7-13
Diagonal Wear — Can be described as localized flat spots worn
diagonally across the tread at approximately 25-35° angles, often
repeating around the tread circumference. For more information, see
TMC RP 219A publication, page 20.
73
Diagonal wear is usually caused by bad wheel bearings, toe out,
mismounting of tire and wheel assembly to axle, and mismatched
duals for size and/or inflation pressures. It may start as brake skid.
Diagonal wear is aggravated by high speed empty or light load
hauls.
To correct diagonal wear, reverse direction of rotation of the tire. If
wear is excessive, true tire. If the source of trouble is the vehicle,
diagnose cause and correct as needed.
FIGURE 7-14
Rapid Shoulder Wear (One
Shoulder Only) — Is defined as a
tire worn on the edge of one
shoulder, sometimes extending to inner ribs. It can
progress to diagonal wipeout. For more information, see
TMC RP 219A publication, page 22.
This wear condition is usually caused by excessive toe
or excessive camber. These conditions can be created by
a misaligned or bent axle and can also be caused by loose or worn wheel bearings.
To correct this type of rapid shoulder wear:
■
Tires – Change direction of rotation of tire. If shoulder wear is severe, remove and
retread.
■
Vehicle – Diagnose misalignment and/or mechanical condition and correct.
FIGURE 7-15
One-sided wear — Is excessive wear on one side of tire
extending from the shoulder towards the center of the
tread. For more information, see TMC RP 219A, page 26.
One-sided wear is usually caused by improper alignment, worn kingpins, loose wheel bearings, excessive
camber, excessive axle loads, non-parallel axles, or
non-uniform tire and wheel assembly caused by
improper bead seating or bent wheel.
To correct one-sided wear:
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■
Tires – Depending on severity, rotate tires to another axle position or, if worn to
minimum tread depths, submit for possible retreading.
■
Vehicle – Diagnose mechanical problem and correct.
31
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AXLE WRAP LINER INSPECTION
FIGURE 7-16
INSPECTION PROCEDURE
■ Axle wrap liners are installed on the STEERTEK
axle to help prevent any type of abrasion on the
axle at the clamp group area. Any time an axle
wrap is removed it is mandatory that the axle
wrap liner be replaced.
■ Liner Crack Criteria:
It is possible for the axle wrap liner to crack during service. If the liner is cracked and all the
pieces are intact it is not necessary to replace the
liner. If the liner is broken out and there are
pieces missing the liner must be replaced immediately, see Figure 7-16. See Axle Wrap
replacement in the Component Replacement
Section of this publication.
74
SHOCK ABSORBER INSPECTION
Hendrickson uses a long service life, premium shock absorber on all AIRTEK and SOFTEK
suspensions. When the shock absorber replacement is necessary, Hendrickson recommends that the shock absorbers be replaced with identical
Hendrickson Genuine parts
for servicing. Failure to do so will affect the suspension performance, durability, and will
void the warranty.
FIGURE 7-17
Inspection of the shock absorber can be performed by
doing a heat test, and a visual inspection. For instructions on shock absorber replacement see the
Component Replacement Section of this publication. It
is not necessary to replace shock absorbers in pairs if
one shock absorber requires replacement.
HEAT TEST
1. Drive the vehicle at moderate speeds on rough
road for minimum of fifteen minutes.
DO NOT GRAB THE SHOCK AS IT CAN POSSIBLY CAUSE
PERSONAL INJURY.
2. Lightly touch the shock body carefully below the
dust cover, see Figure 7-17.
3. Touch the frame to get an ambient reference. A
warm shock absorber is acceptable, a cold shock
absorber should be replaced.
4. To inspect for an internal failure, remove and
shake the suspected shock. Listen for the sound of
metal parts rattling inside. Rattling of metal parts can indicate that the shock has an
internal failure.
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AIRTEK®• SOFTEK® for Blue Bird Buses
VISUAL INSPECTION
Look for these potential problems when doing a visual inspection. Inspect the shock
absorbers fully extended. Replace as necessary.
FIGURE 7-18
75
LEAKING VS. MISTING SHOCK VISUAL INSPECTION
The inspection must not be conducted after driving in wet weather or a vehicle wash; shocks
need to be free from water. Many shocks are often mis-diagnosed as failures. Misting is the
process whereby very small amounts of shock fluid evaporate at a high operating temperature through the upper seal of the shock. When the “mist” reaches the cooler outside air,
it condenses and forms a film on the outside of the shock body. Misting is perfectly normal
and necessary function of the shock. The fluid which evaporates through the seal area helps
to lubricate and prolong the life of the seal.
FIGURE 7-19
A shock that is truly leaking and needs to be
replaced will show signs of fluid leaking in
streams from the upper seal. These streams can
easily be seen when the shock is fully extended,
underneath the main body (dust cover) of the
shock. Look for these potential problems when
doing a visual inspection. Inspect the shock
absorbers fully extended. Replace as necessary.
NOTE
The AIRTEK/SOFTEK suspension is equipped
with a premium seal on the shock, however this
seal will allow for misting to appear on the
shock body (misting is not a leak and is
considered acceptable).
If the shock is damaged, install a new shock
absorber as detailed in the Component Replacement Section of this publication.
17730-248
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KINGPIN BUSHING INSPECTION
INSPECTION PROCEDURE (STEERING KNUCKLE LATERAL MOVEMENT)
1. Chock the wheels to help prevent the vehicle from moving. Set the parking brake.
2. Use a jack to raise the vehicle until the wheels are off the ground. Support the vehicle
with safety stands.
76
FIGURE 7-20
FIGURE 7-21
3. CHECKING THE UPPER KINGPIN BUSHING. Install the base of a dial indicator onto the
axle beam and face the tip against the steering knuckle, see Figure 7-20.
4. Set the dial indicator to “0” zero.
5. Move the top of the tire in and out by applying reasonable constant pressure and then
release, see Figure 7-22.
FIGURE 7-22
6. Check the reading on the dial indicator.
If the dial indicator moves more than
0.015", the upper bushing is worn or
damaged. Replace both bushings. Refer
to the Kingpin Bushing replacement procedure in the Component Replacement
Section of this publication.
7. CHECKING THE LOWER KINGPIN
BUSHING. Install a dial indicator so that
the base is on the axle and the indicator
tip is against the inside of the bottom of
the knuckle, see Figure 7-21.
8. Set the dial indicator to “0” zero.
9. Move the bottom of the tire in and out. If
the dial indicator moves more than
0.015", the lower bushing is worn or
damaged. Replace both kingpin bushings. Refer to the Component
Replacement Section of this publication.
NOTE
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APPENDIX
If one bushing is worn or damaged, it is mandatory to replace both the top and bottom
bushings on that knuckle assembly.
34
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Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
STEERING KNUCKLE INSPECTION
CHECKING VERTICAL END PLAY (UP AND DOWN MOVEMENT)
The operating spec for vertical clearance on the steering knuckle is 0.008" to 0.030".
1. Chock the rear tires to help prevent the vehicle from moving.
2. Set the parking brakes.
3. Use a jack to raise the vehicle until both tires are 1" off the ground.
77
FIGURE 7-23
4. Place a dial indicator on each side of the
axle as follows:
a. Index the wheels slightly (left or
right).
b. Place the magnetic dial indicator
base on the axle, see Figure 7-23.
c. Place the tip of the dial indicator on
the top of the upper steering knuckle
(not on the grease cap).
5. Set the dial indicator to “0” (zero).
6. Lower the jack.
7. If vertical clearance is greater than
0.030", adjust the upper knuckle to
obtain clearance specifications, if adjustment does not achieve clearance
specification, install shims (Hendrickson part no. 60259-002) between the top of the
axle and the bottom of the upper steering knuckle to obtain the proper clearance specification. See Steering Knuckle Assembly in the Component Replacement Section of this
publication for proper shim installation.
8. If vertical clearance is below 0.008", adjust the upper steering knuckle to obtain the
proper clearance specification, if adjustment does not achieve clearance specification,
remove shims. See Steering Knuckle Assembly in the Component Replacement Section
of this publication for proper shim removal.
17730-248
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SHACKLE THRUST WASHER INSPECTION (If Equipped)
NOTE
SOFTEK Vision 8K capacity vehicles built after 02/2007, and all other vehicles built after
11/2006 are not equipped with shackle thrust washers.
In normal use these components will function satisfactorily, even though the components
may show some wear.
78
FIGURE 7-24
Shackle Bracket
M20 Locknut
Tightening Torque
290-310* ft. lbs.
Washer
Shackle Plate
M20 Bolt
Thrust Washer
Leaf Spring with Bushing
*Specification provided, controlled and subject to change by vehicle manufacturer.
An indication that the shackle thrust washers are worn, or need replacement is when the
suspension exhibits one or more of the following conditions:
1. Excessive lateral movement of the spring.
2. The rear spring eye and or thrust washers are in contact with the shackle plates.
3. Normal and unacceptable thickness of the thrust washers (See Figure 7-24) can be
measured with a micrometer or a ruler.
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■
The normal thickness of a new thrust washer is 3⁄16" (0.187").
■
The minimum thickness allowable for a thrust washer is 3⁄32" (0.090").
■
If one or more of these conditions is experienced, disassembly of the rear shackle assembly is required to replace the thrust washers.
■
If one thrust washer is worn out, Hendrickson recommends both thrust washers
on that side of the suspension be replaced. Inspect the thrust washers on the other
side of the vehicle and replace if necessary. See Shackle Thrust Washer replacement procedure in the Component Replacement Section of this publication.
36
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AIRTEK®• SOFTEK® for Blue Bird Buses
FRONT HANGER/REAR SHACKLE BRACKET SURFACE PAINT WEAR
The Hendrickson front suspension systems AIRTEK and SOFTEK equipped on Blue Bird
buses, utilize rubber bushings in the leaf springs. These rubber bushings allow the leaf
spring to deflect and contact the front hanger and shackle plates when the bus encounters
high lateral acceleration (ex. a highway clover leaf). The rubber bushing will center the leaf
spring between the legs of the hanger/shackle plates once the vehicle is driven straight.
79
This function of the rubber bushing may allow the leaf spring to contact the front hanger/rear
shackle plate and possibly remove surface paint from the contact area. Surface paint wear
does not cause damage that will affect the function or durability of the front hanger/rear
shackle plate or their mating components provided a minimum wall thickness is maintained.
FIGURE 7-25
FIGURE 7-26
An indication that the front hanger/ rear
shackle plates are worn and require
replacement is when the components no
longer meet the following minimum
requirements:
17730-248
■
Front hanger inboard leg minimum
thickness of 9.15 mm and the outboard leg thickness minimum
thickness 11.00 mm, see Figure 726.
■
Rear shackle plate minimum thickness of 5.8 mm, see Figure 7-26.
37
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SECTION 8
Alignment & Adjustments
80
ALIGNMENT DEFINITIONS
FIGURE 8-1
Ackermann Steering Geometry —
The geometry of the four bar linkage
ACKERMANN GEOMETRY
consisting of the front axle beam
pivot points, tie rod arms, and cross
tube and attempts to provide free
rolling of front tires in a turn.
Ackermann geometry is dependent
upon the steering axle track-width
and wheelbase of the vehicle.
Rear Axle
Improper geometry results in wheel
Center of Rotation
scrub in turns which generally
appears as toe wear on the tire.
Usually more wear is present on one
side of the vehicle than the other due to the operational route of the vehicle.
Wheel
Base
Bump Steer (Feedback) — The feedback felt through the steering linkage to the steering
wheel when a steer axle tire hits a bump in the road. This occurs because the axle-end of
the drag link and the axle attachment point of the spring do not travel in parallel circular
arcs as the suspension moves up and down. This condition can also be caused by trapped
air in the power steering system.
FIGURE 8-2
Camber — The angle formed by the inward or outward tilt of the
wheel reference to a vertical line. Camber is positive when the
wheel is tilted outward at the top and is negative when the wheel is
tilted inward at the top.
Excessive positive camber may cause smooth wear on the outer half
of the tire tread. Excessive negative camber may cause wear on the
inner half of the tread. Static-unloaded camber angles are built into
the axle to put the loaded tire perpendicular to the road.
FIGURE 8-3
Caster — The forward or rearward
tilt of the steering axle kingpin in
reference to a vertical line. The
angle is measured in degrees.
Caster is positive when the top of
the steering axis is titled rearward
and is negative when the tilt is forward. Proper caster is important
for directional stability and returnability. Too much positive caster
can cause shimmy, excessive
steering effort and is normally a vehicle performance and handling consideration. Uneven
positive caster may create a steering pull toward the side with the lower caster. This attribute may be used to compensate for crowned roads.
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38
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AIRTEK®• SOFTEK® for Blue Bird Buses
FIGURE 8-4
KINGPIN
INCLINATION
IN DEGREES
Kingpin Inclination (KPI) — The inward tilt of the kingpin from the vertical. This
front suspension parameter has a pronounced effect on steering effort and returnability. As the front wheels are turned around an inclined kingpin, the front of the
truck is lifted. This lifting of the vehicle is experienced as steering effort when the
turn is executed and exhibits itself as recovery force when the steering wheel is
released.
81
Kingpin Offset — The distance between the center of the tire patch and intersection of the kingpin axis with the ground. This parameter of front end geometry is
important in vehicles without power steering and has a major effect on static
steering. If there is no kingpin offset, the tires must scrub around the center of the
pin patch when turned in a static condition, resulting in higher static steering
efforts.
KINGPIN
OFFSET
Steering Arm — The component that connects the drag link to the axle knuckle
assembly.
FIGURE 8-5
Thrust Angle, Tracking, or Square
— The angle formed by the centerline of the vehicle frame (geometric
centerline) and the direction that an
axle points. As indicated by the
term “square”, the ideal value for
the angle is 0° or when the axle
centerline is at 90° or perpendicular
to the geometric centerline. Thrust
or tracking to the right is positive, and to the left is negative.
A steering correction is required to offset the effect of the thrust angles and keeps the vehicle traveling in a straight line. It results in a lateral offset between the steer and drive axle
tires commonly referred to as “dog tracking.”
Tie Rod Arm (Ackermann-Arm, Cross Tube Arm) — The component that transmits steering forces between left and right axle knuckle assemblies through the cross tube assembly.
FIGURE 8-6
TOE-IN
Toe-in — is when the horizontal line intersects in front of the wheels, or the
wheels are closer together in front than in the back. Toe-in is commonly
designated as positive, toe-out as negative. Excessive toe-in wears the outside edge of the tires. Steer axle toe is adjustable to reduce wear to the
leading edge of the tire and also to avoid road wander. Toe is adjusted in a
static, unloaded condition so that the tires will run in a straight line under a
dynamic, loaded condition.
FIGURE 8-7
TOE-OUT
17730-248
Toe-out — Is when the horizontal lines intersect behind the wheels, or the
wheels are closer together in back than in front. Toe-in is commonly designated as positive, toe-out as negative. Excessive toe-out wears the
inside edge of the tires. Steer axle toe is adjustable to reduce wear to the
leading edge of the tire and also to avoid road wander. Toe is adjusted in
a static, unloaded condition so that the tires will run in a straight line under
a dynamic, loaded condition.
39
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FIGURE 8-8
Toe-Out on Turns — (See Ackermann Geometry).
Excessive turning angles such as those encountered in pickup and delivery operations may
contribute to premature tire wear. Be advised that
the greater the turning angles, the more that toe
and camber change. If you have any doubt
regarding the optimum turning angles for your
operation, contact the vehicle’s manufacturer, axle
OEM, tire OEM and alignment equipment manufacturer for advice.
82
Total Toe — The angle formed by two horizontal
lines through the planes of two wheels. Steer axle
toe Is adjustable to reduce wear to the leading
edge of the tire and also to avoid road wander. Toe
is adjusted in a static, unloaded condition so that
the tires will run in a straight line under a dynamic, loaded condition.
TOE-OUT
TOE-IN
INSPECTION PRIOR TO ALIGNMENT
WHEELS AND TIRES
Examine the following items:
■ The tires are inflated to the manufacturer’s specified tire pressure.
■ The steer axle tires are the same size and type.
■ The lug nuts are tightened to manufacturer’s specified torque.
■ The wheels are balanced and check for tire to rim runout.
■ The wheels and tires are free of excessive wear and damage.
■ Wheel bearing end play is within OEM specification.
FRONT SUSPENSION
Inspect the following:
■ All fasteners are installed and tightened to the specified torque. See
Torque
Specification Section in the appendix of this publication.
■ Leaf springs are free of wear or damage.
■ Air springs are free of wear or damage (if equipped).
■ Shock absorbers are free of wear and damage.
■ Vehicle ride height for both the front and rear are within specification. Follow manufacturer's guidelines (if equipped).
■ Front and rear spring mounts for wear or damage.
INSPECT TIE ROD ENDS
Perform the “Tie Rod Inspection” procedure, refer to the Preventive Maintenance Section of
this publication.
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40
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Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
REAR AXLE AND REAR SUSPENSION
Rear axle misalignment can cause front tire wear. If the outer edge of one front tire is worn
and the inner edge of the other front tire is worn, check the following:
■ Make sure the rear axle (especially a tandem axle) is correctly aligned. Refer to the procedure from the manufacturer of the vehicle or the suspension.
■ All fasteners including U-bolts (if applicable) are installed and tightened to the specified torque.
■ The leaf springs are not worn or damaged.
■ The bushings in the leaf springs are not worn or damaged.
■ The torque rods (if used) are correctly adjusted (if adjustable).
■ The frame is not bent or twisted.
■ Refer to any additional recommendations and specifications from the manufacturer of
vehicle on rear axles and suspensions. Reference the TMC (The Technology &
Maintenance Council) Guidelines for Total Vehicle Alignment.
83
FRONT WHEEL ALIGNMENT
Hendrickson recommends technicians review TMC’s publication TMC (Technology &
Maintenance Council) “Guidelines for Total Vehicle Alignment”.
The AIRTEK/SOFTEK front wheel alignment specification can be found in the Appendix of this
publication.
Check the total vehicle wheel alignment when the following occur:
■
Every 80,000 to 100,000 miles, or 12-18 months (normal maintenance).
■
When the vehicle does not steer correctly.
■
To correct a tire wear condition.
■
There are two types of front wheel alignment:
1. Minor alignment – a minor front wheel alignment is done for all normal maintenance conditions, see below.
2. Major alignment – a major alignment is done when uneven or excessive tire wear
is evident, or response at the steering wheel is sluggish, or the need for major
wheel alignment check and adjustment is required, see below.
MINOR FRONT WHEEL ALIGNMENT
Perform the minor front wheel alignment in the following sequence:
1. Inspect all systems that affect wheel alignment. Refer to “Inspection Prior to Alignment”
in this section.
2. Check the wheel bearing end play.
3. Check and adjust the vehicle ride height (for AIRTEK) as specified in the Preventive
Maintenance Section of this publication.
4. Check toe-in and adjust if necessary.
MAJOR FRONT WHEEL ALIGNMENT
Be certain to follow wheel alignment inspection intervals as specified by the original equipment manufacturer. Before performing a major front wheel alignment it is recommended
that alignment equipment calibration be checked to ensure proper vehicle alignment.
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Major wheel alignment is accomplished in the following sequence of operation:
1. Inspect all the systems that influence the wheel alignment. Refer to the “Inspection Prior
to Alignment” in this section.
2. Check and adjust the maximum turn angle, (see “Steering Stop Procedure” in this section), see Figures 8-9 and 8-10.
84
3. If the vehicle has power steering, check and adjust, if necessary, the pressure relief in
the power steering system. Refer to vehicle manufacturer’s specifications See Steer
Stops in this section.
4. Verify the turning angle per step 2, (toe-out during vehicle turns or the Ackermann
angle). Refer to vehicle manufacturer's specifications.
FIGURE 8-9
FIGURE 8-10
5. Check the kingpin (or steering axis) inclination (the kingpin inclination is not
adjustable). Refer to “Kingpin Inclination”, in the Alignment Definitions in this section.
6. Check the camber angle. Do not attempt to adjust. Refer to “Camber” in the Alignment
Definitions in this section.
AXLE CAMBER IS NOT ADJUSTABLE. DO NOT CHANGE THE AXLE CAMBER ANGLE OR BEND
THE AXLE BEAM. BENDING THE AXLE BEAM TO CHANGE THE CAMBER ANGLE CAN DAMAGE THE
AXLE AND REDUCE AXLE STRENGTH, AND WILL VOID HENDRICKSON’S WARRANTY. A BENT AXLE
BEAM CAN CAUSE LOSS OF VEHICLE CONTROL, POSSIBLY CAUSING PERSONAL INJURY OR
PROPERTY DAMAGE, SEE FIGURE 8-11.
FIGURE 8-11
7. Check and adjust caster angle. Refer to “Caster” in the Alignment Definitions in this section. The use of two different angle caster shims will not change cross caster. Cross
caster is the difference between the caster readings for left and right side of the vehicle.
SERVICE HINT
Prior to checking caster confirm that the vehicle is at its proper ride height front and rear.
The front and rear ride height must be correct to achieve proper caster.
8. Check and adjust toe-in, refer to adjusting the Toe-In under the Alignment Definitions in
this section.
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AIRTEK®• SOFTEK® for Blue Bird Buses
AIRTEK RIDE HEIGHT ADJUSTMENT
1. Drive the vehicle onto a level surface.
2. Free and center all suspension joints by slowly moving vehicle back and forth several
times without using the brakes. It is important when coming to a complete stop to verify that the brakes are released.
3. Chock front wheels.
NOTE
85
Hendrickson recommends the following be performed during any type of ride height
adjustment to help prevent socket head cap screws from loosening from the height control
valve housing, and any subsequent air leaks from the height control valve.
4. Prior to adjusting the height control valve, clean the threads of the ¼" valve mounting
fasteners to remove any debris and corrosion.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
SERVICE HINT
It is very important that the leveling valve be cycled completely before and after any ride
height adjustments. This cycling of the leveling valve will help to make the adjustment as
accurate as possible.
6. Detach the upper rubber grommet of the height control valve linkage from the upper stud
and exhaust the suspension system air by lowering the height control valve linkage arm.
7. Re-attach the upper grommet of the height control valve linkage onto the upper stud to
fill the suspension system with air. Wait until the airflow to front air springs has stopped.
8. Measure the suspension reference ride height on the shock absorber, see Figures 8-12
and 8-13, measuring from the center of the top mounting bolt to the center of the bottom mounting bolt.
FIGURE 8-12
FIGURE 8-13
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9. The different referenced ride height measurements are as specified in the following
chart. If the reference measurement is not within ± ¼" of the specification, the ride
height MUST be adjusted.
AIRTEK (FRONT)
86
RIDE HEIGHT
Dimension A
Blue Bird Model
Vision 10K
All American Front Engine
All American Rear Engine
COMFORT AIR (REAR)
SHOCK ABSORBER
LENGTH
Dimension B
From the bottom of the
At ride height with a
frame to the center of axle tolerance of ¼"
12½"
147⁄8"
147⁄8"
18 9⁄16"
17¼"
1715⁄32"
RIDE HEIGHT
SHOCK ABSORBER
LENGTH
From the bottom of the
At ride height with a
frame to the bottom of the tolerance of ¼"
main support member.
47⁄8"
22¾"
10. Detach the upper grommet of the height control valve linkage from the stud on the leveling valve arm and exhaust suspension system air, see Figures 8-14 and 8-15.
11. Adjust the height control valve by loosening the ¼" mounting locknuts and pivoting the
valve body about the mounting bolt.
NOTE
It is necessary to place a 3⁄16" Allen wrench in the head of the mounting bolts while
adjusting ride height to prevent movement of the bolts, which can cause air leakage in the
body of the leveling valve.
12. Facing the air spring from the outboard side of the vehicle, pivot the valve body clockwise to increase the ride height and counter clockwise to decrease the ride height.
13. Tighten the ¼" mounting locknuts to
8-10 foot pounds, (see Figures 8-14 and
8-15) and repeat steps 4 through 10 until the reference measurement equals ± ¼" of
the specification, see Figures 8-12 and 8-13.
14. Remove wheel chocks.
FIGURE 8-14
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FIGURE 8-15
44
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Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
AIRTEK HEIGHT CONTROL VALVE TEST
The height control valve test can be done with Barksdale Test Kit (Model 55521).
KIT CONTENTS
QTY.
DESCRIPTION
QTY.
DESCRIPTION
QTY.
DESCRIPTION
1
1
Gauge
(F3) Fitting
1
1
Valve
(T1) Tubing ¼"
2
1
Plug
Fitting
1
Flush Plug
1
Tool
1
O-Ring
87
HEIGHT CONTROL VALVE TEST INSTRUCTIONS
1. Disconnect linkage from valve handle.
2. Lower height control valve linkage arm down to exhaust air from the suspension system.
3. Remove the tubing from both air spring ports, see Figure 8-16. Place supplied tool
around the tubing, press down to pull out tubing. DO NOT CUT THE TUBING.
4. Install the red plugs supplied into the air spring ports.
5. Use needle nose pliers to remove the “flapper” from the valve exhaust port.
FIGURE 8-16
6. Install hex fitting F3 (the one with a small
pin protruding) into the exhaust port. To
install hex fitting into exhaust port align
pin on fitting with slot on exhaust port,
push in and rotate clockwise to stop.
7. Connect one end of the tubing (T1) to this
port and one end into the test gauge valve.
8. Rotate the test gauge valve handle to test
mode, see diagram in Figure 8-16.
9. Rotate handle on valve being tested to fill
mode.
10. Observe pressure reading for a period of
30 seconds.
FIGURE 8-17
11. Refer to chart for maximum
allowable pressure drop vs. inlet
pressure in. 30 seconds, see
Figure 8-17. The valve is good if
the pressure drop does not
exceed the maximum allowable.
12. Rotate vehicle valve handle to
exhaust mode.
13. Rotate test gauge valve handle to
test mode. Repeat steps 10 and
11.
14. Replace valve if maximum allowable drop is exceeded.
This test is complete. Remove the test gauge valve and fitting from the exhaust port. Remove
the red plugs from the air spring ports. Reconnect the air spring tubing to the valve, ensuring that the air lines are pushed fully into the PTC fittings. Reconnect the linkage to the valve
handle. Suspension ride height will automatically return to the correct position.
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AIRTEK®• SOFTEK® for Blue Bird Buses
STEERING STOP
ADJUSTMENT PROCEDURE
When the axle or lower steering knuckle is replaced, the steering stop adjustment must be
checked.
The steering stop adjustment procedure is as follows:
1. Drive truck onto turntables and chock the rear wheels.
2. Measure the wheel cut. The wheel cut is determined by steering the tires. Wheel cut is
measured at the inside wheel only, therefore the tires must be turned to the full lock
position for each right hand and left hand direction. Refer to the vehicle manufacturer
for exact specifications.
3. Increase the wheel cut by loosening the jam nuts and screw the axle stops in clockwise.
4. Tighten the jam nuts.
88
FIGURE 8-18
NOTE
It is very important that the
sides of the square head axle
stops are set parallel to the
axle beam to ensure a good
contact point on the axle, see
Figure 8-18.
5. Decrease the wheel cut
by loosening the jam
nuts and screw the axle
stops out counterclock-wise.
6. Tighten the jam nuts to
40-60 foot pounds torque.
7. Measure the wheel cut and check for any interference with related steering components.
ALWAYS CHECK/RESET THE STEERING GEAR BOX POPPET WHEN THE WHEEL CUT IS
DECREASED. FOLLOW MANUFACTURER'S GUIDELINES FOR THE GEAR BOX POPPET RESETTING
PROCEDURE. FAILURE TO DO SO CAN RESULT IN PREMATURE FAILURE OF THE AXLE OR
STEERING KNUCKLE. THIS CONDITION CAN CAUSE LOSS OF VEHICLE CONTROL, PERSONAL
INJURY OR PROPERTY DAMAGE AND VOID WARRANTY.
TOE SETTING
1. Place the vehicle on a level floor with the wheels in a straight ahead position.
2. Raise the vehicle and support the front axle with jack stands.
3. Use paint and mark the center area of tread on both steer axle tires around the complete outer diameter of the tires.
4. Scribe a line through both steer axle tires in the painted area around the complete outer
diameter of the tires.
5. Raise the vehicle and remove the jack stands.
6. Set the vehicle on the ground.
NOTE
Do not measure toe-in with the front axle off the ground. The weight of the vehicle must be
on the front axle when toe-in is measured.
7. Use a trammel bar and measure the distance between the scribe marks at the rear of
the steer axle tires. Record the measurement.
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8. Install the trammel bar and measure the distance between the scribe marks at the front
of the steer axle tires. Record the measurement, see Figure 8-19.
NOTE
When setting up the trammel bar the pointers should be level with the spindles at the front
and rear of the steer axle tires.
9. To calculate the toe setting subtract the front measurement from the rear measurement,
the difference between the two will equal the toe-in/toe-out measurement.
89
FIGURE 8-19
10. If the toe measurement is not within the specifications of 1/16" ± 1/32"
(0.060" ± 0.030"), it will be necessary to adjust the toe setting. Refer to the following
procedure.
a. Loosen the tie rod cross tube clamp bolts and locknuts.
b. Turn the tie rod cross tube until the specified toe-in distance is achieved.
THE THREADED PORTION OF THE TIE ROD END MUST EXTEND PAST THE SLOTS INTO THE TIE ROD
CROSS TUBE, SEE FIGURE 8-20. FAILURE TO DO SO CAN CAUSE COMPONENT TO FAIL CAUSING
LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
FIGURE 8-20
c. Tighten the bolt and locknut on the tie rod cross tube to
60-75 foot pounds torque.
11. Repeat steps 1-9 until the correct toe setting is achieved.
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AIRTEK®• SOFTEK® for Blue Bird Buses
SPRING EYE RE-TORQUE
This procedure to re-torque is necessary when replacing
■ Front Hanger
90
■
Shackle Assembly
■
Steel Leaf Spring Assembly
AIRTEK RE-TORQUE PROCEDURE
FIGURE 8-21
1. Chock the rear wheels of the vehicle to prevent movement.
2. Verify ride height. Adjust if necessary, see AIRTEK Ride Height adjustment procedure in
this section.
3. Loosen all six (6) front and rear spring eye bolts, see Figure 8-21.
FIGURE 8-22
NOTE
DO NOT remove the spring eye bolts.
4. Let the suspension settle.
5. Tighten the front M20 spring eye bolt locknuts to
vehicle manufacturer's specifications.
6. Tighten the rear M20 spring eye bolt and shackle bolt locknuts to vehicle manufacturer's
specifications.
7. Affix a straight edge to the bottom of the frame
rail in front of the air spring, see Figure 8-22.
8. With the vehicle on a level surface measure the
distance from the top of the straight edge to the
ground on both sides of the vehicle and record
the measurements.
9. Measure the difference from one side to the other.
10. Do a road test and repeat measurement steps
7 to 9.
11. If the measurement is less than 3⁄8" the vehicle is
level. If measurement is more than 3⁄8" contact
Hendrickson Tech Services.
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AIRTEK®• SOFTEK® for Blue Bird Buses
SOFTEK RE-TORQUE PROCEDURE
FIGURE 8-23
91
1. Chock the wheels.
2. Loosen all six (6) front and rear spring eye bolts, see Figure 8-23.
NOTE
Do not remove the spring eye bolts.
3. Let the suspension settle.
4. Tighten the front M20 spring eye bolt locknuts to vehicle manufacturer's specifications.
5. Tighten the rear M20 spring eye bolt and shackle bolt locknuts to vehicle manufacturer's specifications.
6. Affix a straight edge to the bottom of the frame rail behind frame hanger, see Figure 8-22.
7. With the vehicle on a level surface measure the distance from the top of the straight
edge to the ground on both sides of the vehicle and record the measurements.
8. Measure the difference from one side to the other.
9. Do a road test and repeat measurement steps 7 to 9.
10. If the measurement is less than 3⁄8" the vehicle is level. If measurement is more than 3⁄8"
contact Hendrickson Tech Services.
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AIRTEK®• SOFTEK® for Blue Bird Buses
SECTION 9
Component Replacement
FASTENERS
92
Hendrickson recommends that when servicing the vehicle to replace the removed fasteners
with new equivalent fasteners. Maintain correct torque values at all times. Check torque values as specified. See Hendrickson’s Torque Specifications in the Appendix of this
publication. If non-Hendrickson fasteners are used follow torque specifications listed in the
vehicle manufacturer’s service manual.
SPACERS
There are different front axle spacer configurations for each front suspension system. Prior
to disassembly of the front axle clamp group, note the orientation and quantity of the front
axle spacer(s) (if equipped). It is required that the axle spacers be installed in the same
orientation and location as removed to preserve the existing vertical alignment. Refer to the
Parts List Section of this publication.
AIRTEK HEIGHT CONTROL VALVE – 10K
DISASSEMBLY
1. Drain the air from the secondary air tank.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
2. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
3. Deflate the air springs by removing the height control valve linkage at the rubber grommet and lowering the height control linkage arm. This will exhaust the air pressure in
the air springs.
FIGURE 9-1 10K
¼" Nylon Air Line
THE PUSH-TO-CONNECT FITTINGS ARE NONSERVICEABLE. IT IS NECESSARY TO CLEAN THE
DIRT AND DEBRIS AWAY FROM THE PUSH-TOCONNECT FITTINGS AND THE AIR LINES TO HELP
PREVENT ANY FOREIGN MATERIAL FROM
ENTERING THE AIR SPRING, AIR SYSTEM OR
DAMAGING THE PUSH-TO-CONNECT FITTINGS.
CLEAN PUSH-TO-CONNECT FITTINGS USING
SOAPY WATER AND A SOFT BRISTLED BRUSH AND
DRY WITH COMPRESSED AIR.
4. Remove the air lines from the height control
valve, see Figure 9-1. The air lines are
push-to-connect. Push in on the air line to
release tension, push down on the collar
and pull out the air line.
Leveling Valve Arm
Push-to-connect
Fittings
Air Spring Bracket
Air Spring
5. Remove the two ¼" mounting nuts and washers.
6. Remove the height control valve.
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AIRTEK®• SOFTEK® for Blue Bird Buses
ASSEMBLY
1. Attach the height control valve on the vehicle frame as shown in Figure 9-1.
FIGURE 9-2 10K
2. Attach the ¼" washers and the
locknuts. Do not tighten the
locknuts to specified torque
until after the proper ride height
is attained. Mount the height
control valve parallel to flange
of the frame, see Figure 9-2.
SERVICE HINT
93
When replacing or installing nylon
air line tubing into quick-connect
fittings, it is critical that the end of
the air line is cut square. Improper
cut of the end of the air line tubing
can cause the air line to seat
improperly in the quick connect fitting causing air leakage.
FIGURE 9-3 10K
3. Attach the air lines to the height
control valve, see Figure 9-3.
To Left Hand
Air Spring
4. Install the height control valve linkage assembly.
“In” Port
To Right Hand
Air Spring
C1 C2
5. Adjust the height control valve to
proper specifications. See the
Alignment & Adjustments Section of
this publication for proper ride height adjustment.
6. Tighten the ¼" locknuts to
“Exhaust” Port
8-10 foot pounds torque.
AIRTEK HEIGHT CONTROL VALVE – 14.6K
DISASSEMBLY
1. Drain the air from the secondary air tank.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
2. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
3. Deflate the air springs by removing the height control valve linkage at the rubber grommet and lowering the height control linkage arm. This will exhaust the air pressure in
the air springs.
THE PUSH-TO-CONNECT FITTINGS ARE NON-SERVICEABLE. IT IS NECESSARY TO CLEAN THE
DIRT AND DEBRIS AWAY FROM THE PUSH-TO-CONNECT FITTINGS AND THE AIR LINES TO HELP
PREVENT ANY FOREIGN MATERIAL FROM ENTERING THE AIR SPRING, AIR SYSTEM OR
DAMAGING THE PUSH-TO-CONNECT FITTINGS. CLEAN PUSH-TO-CONNECT FITTINGS USING
SOAPY WATER AND A SOFT BRISTLED BRUSH AND DRY WITH COMPRESSED AIR.
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AIRTEK®• SOFTEK® for Blue Bird Buses
FIGURE 9-4 14.6K
¼" Nylon Air Line
4. Remove the air lines from the height control valve, see Figure 9-4. The air lines
are push-to-connect. Push in on the air
line to release tension, push down on the
collar and pull out the air line.
94
5. Remove the two ¼" mounting nuts and
washers.
6. Remove the height control valve.
Air Spring Bracket
Leveling
Valve Arm
Air Spring
ASSEMBLY
1. Re-install the air fittings into the height control valve. Ensure the Teflon® thread sealing ring is seated around the base of the fitting’s hex shoulder. Torque to 3-15 foot
pounds (4-20 Nm).
2. Install the height control valve to the upper air spring bracket by attaching the ¼" washers and locknuts. Torque to 8-10 foot pounds, see Figure 9-5.
FIGURE 9-5 14.6K
3. Install the air lines to the
height control valve. Refer
the Plumbing Diagram
Section of this publication.
PRIOR
TO
AND
DURING
DEFLATION AND INFLATION OF
THE FRONT AIR SUSPENSION
SYSTEM, ENSURE THAT ALL
PERSONNEL AND EQUIPMENT
ARE CLEAR FROM UNDER THE
VEHICLE AND AROUND THE
SERVICE AREA, FAILURE TO DO SO
CAN CAUSE SERIOUS PERSONAL
INJURY, DEATH, OR PROPERTY
DAMAGE.
Rubber
Grommet
¼" Locknuts
Tightening Torque
8-10 ft. lbs.
¼" Washers
Linkage
Assembly
Height Control
Valve
Link
Mount
4. See additional Air Spring
Cautions and Warnings in
the Important Safety otice
Section of this publication prior to inflating or deflating the suspension system.
5. Inflate the suspension by connecting the height control valve linkage to the height control valve arm and lower mounting bracket. Verify the air springs inflate uniformly
without binding.
6. Remove the frame supports.
7. Remove the wheel chocks.
8. Verify proper ride height adjustment, (see ride height adjustment in the Alignment &
Adjustments Section of this publication).
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AIRTEK®• SOFTEK® for Blue Bird Buses
AIRTEK AIR SPRING – 10K
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
95
WHEN SERVICING THE VEHICLE OR ATTACHING AN AIR SPRING AND THE VEHICLE IS ON THE
GROUND, PRIOR TO AIRING THE SUSPENSION SYSTEM MAKE CERTAIN THE AIR SPRING
LOCATOR IS INDEXED INTO THE UPPER AIR SPRING BRACKET PROPERLY, AND THE AIR
SPRING IS FULLY SEATED ON THE SPRING TOP PAD. FAILURE TO FOLLOW THESE
INSTRUCTIONS CAN RESULT IN PREMATURE AIR SPRING FAILURE, CAUSE PERSONAL INJURY,
OR PROPERTY DAMAGE.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
6. Remove the air from the air system by disconnecting the height control valve linkage
at the rubber grommet of the height control valve arm and allow the arm to drop. This
will exhaust air from the system.
IF THE AIR SPRING IS TO BE RE-INSTALLED; INSPECT LOCK-TABS FOR DAMAGE OR CRACKS
PRIOR TO RE-INSTALLATION. CARE MUST BE TAKEN TO REMOVE DIRT AND DEBRIS FROM THE
PUSH-TO-CONNECT FITTING. FAILURE TO DO SO CAN RESULT IN THE PUSH-TO-CONNECT
FITTING FAILING TO SEAL WITH THE AIR LINE.
7. Disconnect the air line to the air spring.
8. Raise the frame to allow for air spring removal.
9. Separate the air spring from the upper air spring bracket by applying downward pressure on air spring, see Figure 9-6, pushing outward on the lock-tabs outside the
bracket, and inward on inlet lock-tabs. This will dislodge the air spring from the upper
air spring bracket.
10. Apply upward pressure between the base of the air spring and the top pad. This will
dislodge the air spring from the top pad, see Figure 9-7.
11. Remove the air spring.
FIGURE 9-6
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FIGURE 9-7
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AIRTEK®• SOFTEK® for Blue Bird Buses
ASSEMBLY
1. Insert the air spring into the top pad. Make sure the lock tabs click in place.
2. Compress the air spring and slide into vertical position. There is a locating nodule on
the air spring to index the position in the upper air spring bracket.
3. Pull the air spring up into the upper air spring bracket until the air spring snaps into
place in the upper air spring bracket. Verify all four lock-tabs are engaged, see
Figure 9-8.
96
FIGURE 9-8
SERVICE HINT
When replacing or installing
nylon air line tubing into
quick-connect fittings it is
critical that the end of the air
line is cut square. Improper
cut of the end of the air line
tubing can cause the air line
to seat improperly in the
quick connect fitting causing
air leakage.
4. Install the air line into the air spring.
WHEN SERVICING THE VEHICLE OR ATTACHING AN AIR SPRING AND THE VEHICLE IS ON THE
GROUND, PRIOR TO AIRING THE SUSPENSION SYSTEM MAKE CERTAIN THE AIR SPRING
LOCATOR IS INDEXED INTO THE UPPER AIR SPRING BRACKET PROPERLY, AND THE AIR
SPRING IS FULLY SEATED ON THE SPRING TOP PAD. FAILURE TO FOLLOW THESE
INSTRUCTIONS CAN RESULT IN PREMATURE AIR SPRING FAILURE, CAUSE PERSONAL INJURY,
OR PROPERTY DAMAGE.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
6. Air up the suspension.
7. Check the air spring for leaks.
8. Check the ride height and adjust if necessary. See Alignment & Adjustments Section of
this publication for the proper ride height adjustment.
9. Remove the wheel chocks.
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AIRTEK®• SOFTEK® for Blue Bird Buses
AIRTEK AIR SPRING – 14.6K
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
97
WHEN SERVICING THE VEHICLE OR ATTACHING AN AIR SPRING AND THE VEHICLE IS ON THE
GROUND, PRIOR TO AIRING THE SUSPENSION SYSTEM MAKE CERTAIN THE AIR SPRING
LOCATOR IS INDEXED INTO THE UPPER AIR SPRING BRACKET PROPERLY, AND THE AIR
SPRING IS FULLY SEATED ON THE SPRING TOP PAD. FAILURE TO FOLLOW THESE
INSTRUCTIONS CAN RESULT IN PREMATURE AIR SPRING FAILURE, CAUSE PERSONAL INJURY,
OR PROPERTY DAMAGE.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
6. Remove the air from the air system by disconnecting the height control valve linkage(s)
at the rubber grommet(s) and allowing the lever(s) to drop. This will exhaust air from
the system.
7. If the air spring is damaged and the suspension is deflated, it will be necessary to raise
the frame and support the vehicle with frame stands to obtain adequate clearance for
air spring removal.
8. Disconnect the ¼" NPT air fitting from the air spring.
9. Remove the lower ½" air spring locknut from the piston stud to remove the air spring
from the top pad, see Figure 9-9.
FIGURE 9-9
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10. Remove the ¾" upper air spring locknut from the air spring bracket.
11. Remove the air spring.
ASSEMBLY
1. Compress the air spring and slide into vertical position.
2. There is a locating ½" stud and ¾" threading stud on top of the air spring.
3. There are two studs on the bottom of the air spring. Guide studs through the air spring
bracket and properly seat the lower air spring piston into the top axle pad. Secure the
½" locknut to the piston, see Figure 9-10.
98
FIGURE 9-10
4. Tighten the ¾" upper air spring locknuts to vehicle manufacturer's specifications and
the lower ½" lower air spring locknuts to 20-30 foot pounds.
WHEN SERVICING THE VEHICLE OR ATTACHING AN AIR SPRING AND THE VEHICLE IS ON THE
GROUND, PRIOR TO AIRING THE SUSPENSION SYSTEM MAKE CERTAIN THE AIR SPRING
LOCATOR IS INDEXED INTO THE UPPER AIR SPRING BRACKET PROPERLY, AND THE AIR
SPRING IS FULLY SEATED ON THE SPRING TOP PAD. FAILURE TO FOLLOW THESE
INSTRUCTIONS CAN RESULT IN PREMATURE AIR SPRING FAILURE, CAUSE PERSONAL INJURY,
OR PROPERTY DAMAGE.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
6. Install the air line into the air spring.
7. Air up the suspension.
8. Check the air spring for leaks.
9. Check the ride height and adjust if necessary. See Alignment & Adjustments Section of
this publication for the proper ride height adjustment.
10. Remove the wheel chocks.
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AIRTEK FRONT LEAF SPRING FRAME HANGER
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Suspend the front axle from the shock absorbers.
99
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
6. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
7. Deflate the air springs by removing the height control valve linkage and lowering the
leveling valve arm. This will exhaust the air pressure in the air springs.
8. Remove the air lines from air springs.
9. Remove the M20 spring eye bolt, washers and locknut.
SERVICE HINT
A bottle jack may be required to raise the axle slightly to facilitate removal of the spring
eye bolt.
10. Remove the frame mounting fasteners from the hanger. See manufacturer's guidelines.
11. Remove the hanger from the vehicle, see Figure 9-11.
FIGURE 9-11
ASSEMBLY
1. Install the new hanger on the frame.
2. Install new frame fasteners. Follow manufacturer's guidelines.
3. Install the new M20 spring eye bolt from the outboard side of the hanger (see Figure
9-11), washers and locknut.
4. Remove the frame stands and lower frame.
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
100
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
6. Install the air lines into the air springs.
7. Install the height control valve linkage and inflate the suspension to normal operating
pressure.
8. Tighten M20 locknut to vehicle manufacturer's specifications.
9. Remove the wheel chocks.
SOFTEK FRONT LEAF SPRING FRAME HANGER
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Suspend the front axle from the shocks.
6. Remove the M20 spring eye bolt, washers and locknut.
SERVICE HINT
A bottle jack may be required to raise the axle slightly to facilitate removal of the spring
eye bolt.
7. Remove the frame mounting fasteners from the hanger. See manufacturer's guidelines.
8. Remove the hanger from the vehicle, see Figure 9-12.
FIGURE 9-12
ASSEMBLY
1. Install the new hanger on the frame.
2. Install new frame fasteners. Follow manufacturer's guidelines.
3. Install the new M20 spring eye bolt from the outboard side of the hanger (see Figure
9-12), washers and locknut.
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4. Remove the frame stands and lower frame.
5. Tighten M20 shackle locknut to vehicle manufacturer's specifications.
6. Remove the wheel chocks.
AIRTEK REAR SHACKLE FRAME BRACKET
101
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Suspend the front axle from the shocks.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
6. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
7. Deflate the air springs by removing the height control valve linkage and lowering the
leveling valve arm. This will exhaust the air pressure in the air springs.
8. Remove the air lines from air springs.
9. Remove the rear M20 spring eye and shackle pivot bolts, washers and locknuts.
SERVICE HINT
A bottle jack may be required to raise the axle slightly to facilitate removal of the rear spring
eye bolt.
10. Remove the frame fasteners from the shackle bracket. See manufacturer's guidelines.
11. Remove the shackle bracket from the vehicle, see Figures 9-13 and 9-14.
12. Inspect the shackle assembly and both thrust washers (if equipped) for excessive wear
or damage. See Thrust Washer Inspection in the Preventive Maintenance Section of this
publication. Hendrickson recommends the thrust washers be replaced when this
assembly is serviced.
13. If damaged or worn excessively, replace with Genuine Hendrickson Parts as detailed
in the Component Replacement Section of this publication.
FIGURE 9-13
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FIGURE 9-14
102
ASSEMBLY
1. Install the shackle bracket on the frame.
2. Install new frame fasteners. Follow manufacturer's guidelines.
3. Install the thrust washers (if equipped) and shackle plates with the M20 bolts, washers and locknuts. Snug the shackle bolts. DO NOT tighten.
4. Remove the frame stands and lower frame.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
6. Install the air lines into the air springs.
7. Install the height control valve linkage and inflate the suspension to normal ride height.
8. Tighten M20 shackle locknuts to vehicle manufacturer's specifications, see Figures
9-13 and 9-14.
9. Remove the wheel chocks.
SOFTEK REAR SHACKLE BRACKET
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Suspend the front axle from the shocks.
6. Remove the rear M20 spring eye and shackle pivot bolts, washers and locknuts.
SERVICE HINT
A bottle jack may be required to raise the axle slightly to facilitate removal of the rear spring
eye bolt.
7. Remove the frame fasteners from the shackle bracket. See manufacturer's guidelines.
8. Remove the shackle bracket from the vehicle, see Figures 9-15 and 9-16.
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9. Inspect the shackle assembly and both thrust washers (if equipped) for excessive wear or
damage. See Thrust Washer Inspection in the Preventive Maintenance Section of this publication. Hendrickson recommends the thrust washers be replaced when this assembly is
serviced.
10. If damaged or worn excessively, replace with Genuine Hendrickson Parts as detailed
in the Component Replacement Section of this publication.
FIGURE 9-15
103
FIGURE 9-16
ASSEMBLY
1. Install the shackle bracket on the frame.
2. Install new frame fasteners. Follow manufacturer's guidelines.
3. Install the thrust washers (if equipped) and shackle plates with the M20 bolts, washers and locknuts, see Figures 9-15 and 9-16.
4. Remove the frame stands and lower frame.
5. Tighten M20 locknuts to vehicle manufacturer's specifications.
6. Remove the wheel chocks.
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
SOFTEK RUBBER AXLE STOP
FIGURE 9-17
8K/10K
13.2K/14.6K
Rubber Stop
REMOVAL
1. Insert a small pry bar
Top Pad
between the rubber stop
and the inside of the top
pad.
2. Apply downward force
on the pry bar and pull
the rubber stop out of
the top pad, see Figure
9-17.
3. Inspect the top pad and frame rail flange for any contact damage.
4. Clean any debris from inside the top pad.
104
Rubber Stop
Top Pad
INSTALLATION
1. Lubricate the new rubber axle stop with soapy water.
2. Install the rubber axle stop in the top pad.
3. Apply downward force on the rubber axle stop until it is seated firmly in the top pad.
AIRTEK THRUST WASHERS (If Equipped)
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
6. Deflate the air springs by removing the height control valve linkage and lowering the
leveling valve arm. This will exhaust the air pressure in the air springs.
7. Suspend the front axle from the shocks.
8. Remove the M20 spring eye and shackle pivot bolts, washers and locknuts.
9. Remove the shackle plates and thrust washers (if equipped).
ASSEMBLY
1. Install the NEW thrust washers (if equipped) and shackle plates with the M20 bolts,
washers and locknuts, see Figure 9-14.
2. Remove frame stands and lower frame.
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AIRTEK®• SOFTEK® for Blue Bird Buses
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
3. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
105
4. Install air lines into the air springs.
5. Install the height control valve linkage and inflate the suspension to normal ride height.
6. Tighten M20 locknuts to vehicle manufacturer's specifications.
7. Remove the wheel chocks.
SOFTEK THRUST WASHERS (If Equipped)
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Suspend the front axle from the shocks.
6. Remove the M20 spring eye and shackle pivot bolts, washers and locknuts.
7. Remove the shackle plates and thrust washers (if equipped).
ASSEMBLY
1. Install the NEW thrust washers (if equipped) and shackle plates with the M20 bolts,
washers and locknuts, see Figure 9-16.
2. Remove frame stands and lower frame.
3. Tighten M20 locknuts to vehicle manufacturer's specifications.
4. Remove the wheel chocks.
AIRTEK LEAF SPRING ASSEMBLY
DISASSEMBLY
1. Place the vehicle on a level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
6. Deflate the air springs by removing the height control valve linkage and lowering the
height control valve arm. This will exhaust the air pressure in the air springs.
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THE PUSH-TO-CONNECT FITTINGS ARE NON-SERVICEABLE. IT IS NECESSARY TO CLEAN THE
DIRT AND DEBRIS AWAY FROM THE PUSH-TO-CONNECT FITTINGS AND THE AIR LINES TO HELP
PREVENT ANY FOREIGN MATERIAL FROM ENTERING THE AIR SPRING, AIR SYSTEM OR
DAMAGING THE PUSH-TO-CONNECT FITTINGS. CLEAN PUSH-TO-CONNECT FITTINGS USING
SOAPY WATER AND A SOFT BRISTLED BRUSH AND DRY WITH COMPRESSED AIR.
106
7. Disconnect the air lines at the air springs.
8. Suspend the front axle to remove the load from leaf spring assembly.
9. Remove the air spring (see Air Spring disassembly in this section).
10. Remove the front and rear M20 spring eye bolts washer and locknuts. Loosen the M20
shackle pivot bolt.
SERVICE HINT
To ease in the removal of the spring eye bolts, it may be necessary to raise the axle slightly.
FIGURE 9-18
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11. Remove the ¾" clamp group locknuts and discard.
DO NOT USE A CUTTING TORCH TO REMOVE CLAMP GROUP BOLTS OR ATTACHING
FASTENERS. THE USE OF SUCH HEAT ON SUSPENSION COMPONENTS CAN ADVERSELY AFFECT
THE STRENGTH OF THESE PARTS. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN
THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
SERVICE HINT
If a clamp group nut fails to come off bolt, cut half way through the bolt with an abrasive
cut off wheel, taking care not to contact axle beam or other components. Using an impact
wrench, spin the locknut to fracture the bolt and remove.
107
12. Remove the ¾" clamp group bolts, the top pad, galvanized liner and the bottom axle
wrap and liner. Discard the clamp group bolts, see Figure 9-18.
13. Remove the spring assembly.
ASSEMBLY
1. Install the new spring and wrap leaf assembly on the axle. Verify the center bolt is located properly in the top axle wrap and spacer (if equipped), see Figure 9-18.
2. Install the new galvanized liner and the top pad onto the spring.
3. Remove and replace the bottom axle wrap liner located in bottom axle wrap.
4. Install the bottom axle wrap.
5. Install the new ¾" clamp group bolts, washers, and locknuts. New clamp group fasteners must be used when the clamp group is removed, to prevent premature bolt
fatigue.
6. Snug the clamp group, DO NOT torque at this time.
7. Raise the axle and the spring assembly into the front hanger and rear shackle
assembly.
8. Install the M20 spring eye bolts, washers and locknuts. Snug bolts. Do not tighten.
9. Ensure that the clamp group is properly aligned and the hex bolts are seated in the top
pad, and the bottom axle wrap is centered with the top axle wrap, see Figure 9-19.
FIGURE 9-19
FIGURE 9-20
10. Tighten the clamp group locknuts evenly in 50 foot pounds increments
to 285-305 foot pounds torque in the proper pattern to achieve uniform bolt tension, see Figure 9-20.
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
108
11. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
12. Install air spring.
13. Install air lines, and air up system.
14. Remove the frame supports and load the front axle with the vehicle weight.
15. Verify proper ride height. See Alignment & Adjustments Section of this publication.
16. Tighten the M20 spring eye bolt locknuts to vehicle manufacturer's specifications.
SOFTEK LEAF SPRING ASSEMBLY
DISASSEMBLY
1. Place the vehicle on a level floor.
2. Chock the wheels.
3. Raise the vehicle.
4. Support the vehicle with frame stands.
5. Suspend the front axle to remove the load from leaf spring assembly.
6. Remove the front and rear M20 spring eye bolts washer and locknuts. Loosen the M20
shackle pivot bolt.
SERVICE HINT
To ease in the removal of the spring eye bolts, it may be necessary to raise the axle slightly.
7. Remove the ¾" clamp group U-bolts, washers and locknuts. Discard the fasteners.
DO NOT USE A CUTTING TORCH TO REMOVE CLAMP GROUP BOLTS OR ATTACHING
FASTENERS. THE USE OF SUCH HEAT ON SUSPENSION COMPONENTS CAN ADVERSELY AFFECT
THE STRENGTH OF THESE PARTS. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN
THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
SERVICE HINT
If a clamp group nut fails to come off bolt, cut half way through the bolt with an abrasive
cut off wheel, taking care not to contact axle beam or other components. Using an impact
wrench, spin the locknut to fracture the bolt and remove.
8. Remove the top pad, galvanized liner and the bottom axle wrap, see Figure 9-21.
9. Remove the spring assembly.
ASSEMBLY
1. Install the new spring and wrap leaf assembly on the axle. Verify that the center bolt is
located properly in the top axle wrap and spacer (if equipped), see Figure 9-21.
2. Install the new galvanized liner and the top pad onto the spring.
3. Remove and replace the bottom axle wrap liner located in bottom axle wrap.
4. Install the bottom axle wrap.
5. Install the new ¾" clamp group U-bolts, washers, and locknuts. The locknuts must be
replaced when the clamp group is removed, to prevent premature bolt fatigue.
6. Snug the clamp group, DO NOT torque at this time.
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FIGURE 9-21
Front Hanger
M20 Bolt
109
Rear Hanger
Shock Absorber
M20 Locknut
Tightening Torque
*290-310 ft. lbs.
¾" Lower
Shock Bolt
M20 Bolt
M20 Washer
Leaf Spring
¾" Lower
Shock Locknut
Tightening Torque
*125-135 ft. lbs.
Rear Shackle Plate
M20 Locknut
Tightening Torque
*290-310 ft. lbs.
Dowel Pin
Axle Spacer
Axle & Kingpin Assembly
Top Wrap
Bottom Axle Wrap Liner
Bottom Axle Wrap
¾" Clamp Group Locknut
Tightening Torque
285-305 ft. lbs.
¾" Washer
* Specification provided,
controlled and subject
to change by
vehicle manufacturer.
FIGURE 9-22
7. Raise the axle and the spring and wrap leaf
assembly into the front hanger and rear shackle
assembly.
8. Install the M20 spring eye bolts, washers and
locknuts. Snug bolts. Do not tighten.
9. Ensure that the clamp group is properly aligned
and the U-bolts are seated in the top pad, and
the bottom axle wrap is centered with the top
axle wrap, see Figure 9-22.
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FIGURE 9-23
10. Tighten the clamp group locknuts evenly in 50 foot pounds increments
to 285-305 foot pounds torque in the proper pattern to achieve uniform bolt tension, see Figure 9-23.
11. Remove the frame supports and load the front axle with the vehicle
weight.
110
12. Tighten the M20 spring eye bolt locknuts to vehicle manufacturer's specifications.
FRONT LEAF SPRING EYE BUSHINGS
The spring eye bushings for the AIRTEK and SOFTEK spring and wrap leaf assemblies are
designed to provide extended service life. If premature wear occurs careful consideration
must be given to the contributing factor that caused the wear. This must be corrected in
order to prevent the new bushing from wearing in the same manner. The front and rear
bushings are permanently installed in the spring leaf and are not serviceable. If a bushing
wears prematurely, the spring and wrap leaf assembly must be replaced. Follow the procedure for the Front Leaf Spring removal in the Component Replacement Section of this
publication.
AIRTEK/SOFTEK SHOCK ABSORBER – VISION (8K/10K)
It is not necessary to replace shock absorbers in pairs if only one shock requires replacement.
DISASSEMBLY
1. Remove the ¾" lower mounting bolt, fasteners, and spacer.
2. Remove the ¾" upper mounting bolt and fasteners.
3. Slide the shock absorber out of the upper bracket and off of the lower mounting bolt.
4. Inspect the shock absorber mounting brackets and hardware for damage or wear,
replace as necessary.
FIGURE 9-24
Shock
Absorber
¾" Bolt
¾" Washer
Top Axle Wrap
Spacer
¾" Washer
¾" Lower Shock Locknut
Tightening torque
*125-135 ft. lbs.
Apply a thin coating
of anti-seize compound
to the shock absorber
lower mounting bolt shank,
to the mating face of the axle wrap,
and spacer, and to the inside bore
of the aluminum top axle wrap
*Specification provided, controlled and subject to change by vehicle manufacturer.
ASSEMBLY
1. Install the shock absorber into the upper mounting bracket.
2. Install the upper ¾" shock mounting bolt, washers and locknut.
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3. Apply a thin coating of anti-seize compound to the shock absorber lower mounting bolt
shank, to the mating face of the axle wrap and spacer, and to the inside bore of the
aluminum axle wrap. This is necessary to help prevent seizing of the bolt to the aluminum axle wrap.
4. Install the lower ¾" bolt from the inboard side to the outboard side of the top axle wrap
and attach the spacer, washer, and locknut, see Figure 9-24.
111
5. Tighten both upper and lower ¾" locknuts to vehicle manufacturer's specifications, see
Figure 9-24.
AIRTEK/SOFTEK SHOCK ABSORBER – ALL AMERICAN (13.2K/14.6K)
It is not necessary to replace shock absorbers in pairs if only one shock requires replacement.
DISASSEMBLY
1. Remove the ¾" lower mounting bolt, fasteners, and spacer.
2. Remove the ¾" upper mounting bolt and fasteners.
3. Slide the shock absorber out of the lower bracket and off of the lower mounting bolt.
4. Inspect the shock absorber mounting brackets and hardware for damage or wear,
replace as necessary.
FIGURE 9-25
AIRTEK 14.6K
FIGURE 9-26
SOFTEK 13.2K/14.6K
Shock Absorber
Shock Absorber
Spacer
Top Pad
Top Pad
¾" Bolt
¾" Bolt
¾" Washer
¾" Washer
Spacer
¾" Washer
¾" Lower Shock Locknut
Tightening torque
*125-135 ft. lbs.
¾" Washer
¾" Lower Shock Locknut
Tightening torque
*125-135 ft. lbs.
*Specification provided, controlled and subject to change by vehicle manufacturer.
ASSEMBLY
1. Install the shock absorber into the upper mounting bracket.
2. Install the upper ¾" shock mounting bolt, washers and locknut.
3. Install the lower ¾" bolt from the inboard side to the outboard side of the top axle wrap
and attach the spacer, washer, and locknut, see Figures 9-25 and 9-26.
4. Tighten both upper and lower ¾" locknuts to vehicle manufacturer's specifications, see
Figures 9-25 and 9-26.
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AIRTEK®• SOFTEK® for Blue Bird Buses
AIRTEK BOTTOM AXLE WRAP
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
112
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
5. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
6. Deflate the air springs by disconnecting the height control valve linkage and lowering
the height control valve arm. This will exhaust the air pressure in the air springs.
DO NOT USE A CUTTING TORCH TO REMOVE CLAMP GROUP BOLTS OR ATTACHING
FASTENERS. THE USE OF SUCH HEAT ON SUSPENSION COMPONENTS CAN ADVERSELY AFFECT
THE STRENGTH OF THESE PARTS. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN
THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
SERVICE HINT
If a clamp group nut fails to come off bolt, cut half way through the bolt with an abrasive
cut off wheel, taking care not to contact axle beam or other components. Using an impact
wrench, spin the locknut to fracture the bolt and remove.
7. Remove ¾" hex bolts, washers and locknuts. Removal of the air spring will be
required. See Air Spring Replacement instructions in this section. Discard fasteners.
8. Remove bottom axle wrap. It may be necessary to use a dead blow mallet to dislodge
axle wrap.
9. Once removed inspect axle wrap for damage. Replace if necessary.
10. Discard used bottom axle wrap liner.
ASSEMBLY
1. Install new bottom axle wrap liner into bottom axle wrap.
2. Install bottom axle wrap on axle.
FIGURE 9-27 AIRTEK
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3. Install new ¾" clamp group bolts, washers and locknuts. Ensure that the clamp group
is properly aligned and the hex bolts are seated in the top pad, and the bottom axle
wrap is centered on the top axle wrap, see Figure 9-27.
FIGURE 9-28
4. Tighten locknuts evenly to 285-305 foot pounds torque, see Figure
9-28 for proper torque sequence.
113
5. Install Air spring. See Air Spring assembly in this section.
6. Remove the wheel chocks.
SOFTEK BOTTOM AXLE WRAP
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
DO NOT USE A CUTTING TORCH TO REMOVE CLAMP GROUP BOLTS OR ATTACHING
FASTENERS. THE USE OF SUCH HEAT ON SUSPENSION COMPONENTS CAN ADVERSELY AFFECT
THE STRENGTH OF THESE PARTS. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN
THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
SERVICE HINT
If a clamp group nut fails to come off bolt, cut half way through the bolt with an abrasive
cut off wheel, taking care not to contact axle beam or other components. Using an impact
wrench, spin the locknut to fracture the bolt and remove.
5. Remove ¾" U-bolts, washers and locknuts. Discard fasteners.
6. Remove bottom axle wrap. It may be necessary to use a dead blow mallet to dislodge
axle wrap.
7. Once removed inspect axle wrap for damage. Replace if necessary.
8. Discard used bottom axle wrap liner.
ASSEMBLY
FIGURE 9-29 SOFTEK
1. Install new bottom axle wrap liner into bottom axle
wrap.
2. Install bottom axle wrap on axle.
3. Install new ¾" U-bolts, washers and locknuts.
Ensure that the clamp group is properly aligned
and the U-bolts are seated in the top pad, and the
bottom axle wrap is centered with the top axle
wrap, see Figure 9-29.
4. Tighten locknuts evenly to 285-305 foot pounds
torque, see Figure 9-28 for proper torque sequence.
5. Remove the wheel chocks.
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
AIRTEK TOP AXLE WRAP (In Chassis)
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Suspend the front axle to remove the load from the spring and wrap leaf assembly.
114
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
6. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
AIR SPRINGS MUST BE DEFLATED PRIOR TO LOOSENING ANY CLAMP GROUP HARDWARE.
UNCONSTRAINED AIR SPRINGS CAN VIOLENTLY SHIFT, RESULTING IN POSSIBLE PERSONAL
INJURY, DEATH OR PROPERTY DAMAGE.
7. Deflate the air springs by disconnecting the height control valve linkage and lowering
the height control valve arm. This will exhaust the air pressure in the air springs.
8. Disconnect the air lines at the air springs.
9. Remove the air spring (See Air Spring disassembly in this section).
10. Support the axle with a jack.
11. Remove the front and rear M20 spring eye bolts, washers and locknuts.
SERVICE HINT
A bottle jack may be required to raise the axle slightly in order to remove spring eye bolts.
DO NOT USE A CUTTING TORCH TO REMOVE CLAMP GROUP BOLTS OR ATTACHING
FASTENERS. THE USE OF SUCH HEAT ON SUSPENSION COMPONENTS CAN ADVERSELY AFFECT
THE STRENGTH OF THESE PARTS. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN
THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
SERVICE HINT
If a clamp group nut fails to come off bolt, cut half way through the bolt with an abrasive
cut off wheel, taking care not to contact axle beam or other components. Using an impact
wrench, spin the locknut to fracture the bolt and remove.
12. Remove the ¾" clamp group bolts, washers and locknuts. Discard fasteners.
13. Remove the top pad, the galvanized liner, and the bottom axle wrap.
14. Remove the lower shock mounting bolt.
15. Remove the spring and wrap leaf assembly
16. Strike the axle wrap with a dead blow mallet at the front and rear on the underside of
the axle wrap to dislodge it from the axle, see Figure 9-30.
17. Clean and inspect the axle wrap and axle wrap line for cracks or damage, replace each
if cracks or damage are present.
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FIGURE 9-30
115
ASSEMBLY
1. Install the new axle wrap liner on the axle.
2. Spray the axle wrap liner and the axle wrap with a silicon lubricant.
3. Position the axle wrap on the axle, see Figure 9-31.
DO NOT STRIKE THE TOP AXLE WRAP WITH A HAMMER. HENDRICKSON RECOMMENDS USING
A PLASTIC DEAD BLOW MALLET WITH CARE WHEN INSTALLING THE AXLE WRAP.
FIGURE 9-31
4. Protect the top surface of the axle
wrap with a block of wood, cardboard, or shop towels.
5. Install a bottle jack between the axle
wrap and frame rail flange.
6. Jack the axle wrap down into position
on the axle, using care to make sure
the axle wrap bore indexes the locating bushing on the axle.
IMPORTANT NOTE
14.6K Top
Axle Wrap
Top Axle
Wrap Liner
Axle Wrap
Guide Pin
10K Top
Axle Wrap
Axle
For Flat Floor Models install the
intermediate dowel pin into the axle wrap.
7. Install the spring and wrap leaf
assembly on the axle wrap (indexing
the dowel pin if equipped).
8. Install the galvanized liner and the top
pad on the spring and wrap leaf assembly.
9. Remove and replace the bottom axle wrap liner.
10. Install the bottom axle wrap.
11. Install the new ¾" clamp group bolts, washers, and locknuts.
12. Snug the clamp group, DO NOT torque at this time.
13. Use a jack and raise the axle and spring assembly into the front spring hanger and
shackle assembly.
SERVICE HINT
A bottle jack may be required to raise the axle slightly in order to install the spring eye bolts.
14. Install the M20 spring eye bolts in the front spring hanger and rear shackle assembly.
15. Ensure that the clamp group is properly aligned and the hex bolts are seated in the top pad,
and the bottom axle wrap is centered with the top axle wrap, see Figure 9-32.
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FIGURE 9-32
116
FIGURE 9-33
16. Tighten the ¾" clamp group locknuts evenly to
285-305 foot
pounds torque in the proper sequence, see Figure 9-33.
17. Remove the jack from the axle.
18. Remove the frame stands.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
19. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
20. Attach air lines to the air springs.
21. Install shocks. (See shock absorber assembly in this section)
22. Air up system to proper ride height. (See Ride Height Adjustment in the Alignment &
Adjustments Section of this publication).
23. Tighten the M20 spring eye bolt locknuts to vehicle manufacturer's specifications, see
Figure 9-34.
24. Remove the wheel chocks.
FIGURE 9-34
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SOFTEK TOP AXLE WRAP (In Chassis)
DISASSEMBLY
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Suspend the front axle to remove the load from the spring and wrap leaf assembly.
6. Remove the front and rear M20 spring eye bolts, washers and locknuts. Loosen the
M20 shackle pivot bolt.
SERVICE HINT
117
A bottle jack may be required to raise the axle slightly in order to remove spring eye bolts.
7. Support the axle with a jack.
DO NOT USE A CUTTING TORCH TO REMOVE CLAMP GROUP BOLTS OR ATTACHING
FASTENERS. THE USE OF SUCH HEAT ON SUSPENSION COMPONENTS CAN ADVERSELY AFFECT
THE STRENGTH OF THESE PARTS. A COMPONENT DAMAGED IN THIS MANNER CAN RESULT IN
THE LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
SERVICE HINT
If a clamp group nut fails to come off bolt, cut half way through the bolt with an abrasive
cut off wheel, taking care not to contact axle beam or other components. Using an impact
wrench, spin the locknut to fracture the bolt and remove.
8. Remove the ¾" clamp group U-bolts, washers and locknuts. Discard fasteners.
9. Remove the top pad and the bottom axle wrap.
10. Remove the lower shock mounting bolt.
11. Remove the spring and wrap leaf assembly.
12. Strike the axle wrap with a dead blow mallet at the front and rear on the underside of
the axle wrap to dislodge it from the axle, see Figure 9-35.
13. Clean and inspect the axle wrap and axle wrap liners for cracks or damage, replace
each if cracks or damage are present.
FIGURE 9-35
ASSEMBLY
1. Install the new axle wrap liner on the axle.
2. Spray the axle wrap liner and the axle wrap with a silicon lubricant.
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AIRTEK®• SOFTEK® for Blue Bird Buses
FIGURE 9-36
3. Position the axle wrap on the axle, see
Figure 9-36.
DO NOT STRIKE THE TOP AXLE WRAP WITH
A HAMMER. HENDRICKSON RECOMMENDS
USING A PLASTIC DEAD BLOW MALLET WITH
CARE WHEN INSTALLING THE AXLE WRAP.
118
4. Protect the top surface of the axle wrap
with a block of wood, cardboard, or
shop towels.
13.2K/14.6K
Top Axle Wrap
Top Axle
Wrap Liner
8K/10K Top
Axle Wrap
Axle Wrap
Guide Pin
Axle
5. Install a bottle jack between the axle
wrap and frame rail flange.
6. Jack the axle wrap down into position
on the axle, using care to make sure
the axle wrap bore indexes the locating
bushing on the axle.
7. Install the spring and wrap leaf assembly on the axle wrap indexing the center bolt in
the locating hole.
8. Install the top pad on the spring and wrap leaf assembly.
9. Remove and replace the bottom axle wrap liner.
10. Install the bottom axle wrap.
11. Install the new ¾" clamp group U-bolts, washers, and locknuts.
12. Snug the clamp group, DO NOT torque at this time.
FIGURE 9-37 SOFTEK
13. Use a jack and raise the axle and spring assembly into the front spring hanger and shackle
assembly.
SERVICE HINT
A bottle jack may be required to raise the axle slightly
in order to install the spring eye bolts.
14. Install the M20 spring eye bolts, washer and
locknuts in the front spring hanger and rear
shackle assembly.
15. Ensure that the clamp group is properly aligned
and the U-bolts are seated in the top pad, and the
bottom axle wrap is centered with the top axle
wrap, see Figure 9-37.
FIGURE 9-38
16. Tighten the ¾" clamp group locknuts evenly to
285-305 foot
pounds torque in the proper sequence, see Figure 9-38.
17. Apply a thin coating of anti-seize to the lower shock mounting bolt.
18. Install shocks. (See shock absorber assembly in this section)
19. Remove the jack from the axle.
20. Remove the frame stands.
21. Tighten the M20 spring eye bolt locknuts to vehicle manufacturer's specifications.
22. Remove the wheel chocks.
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AIRTEK®• SOFTEK® for Blue Bird Buses
AIRTEK FRONT AXLE ASSEMBLY
STEERTEK AXLE CLAMP GROUP CONSIST OF THE FOLLOWING COMPONENTS:
■ Top axle wrap
■ Bottom axle wrap
■ Top axle wrap liner
■ Bottom axle wrap liner
■ Top pad
■ ¾" Bolts, washers and nylon locknuts
119
FIGURE 9-39
SHOWN AIRTEK 10K
Height Control
Valve Linkage
Spring Eye Bolt
Leaf Spring
Air Spring
RH Upper
Steering Knuckle
Top Pad
Lower Shock Locknut
Rear Shackle
Assembly
¾" Bolts
LH Upper
Steering Knuckle
Spacer
King Pin Bushing
Top Axle
Wrap
Roller
Bearing
King Pin Seal
RH Lower
Steering Knuckle
Axle & King
Pin Assembly
Composite Bearing
Castle Nut
Bottom Axle
Wrap Liner
LH Lower
Steering Knuckle
Cap Screws
Bottom Wrap
Cotter
Pin
/ " Washer
7 8
¾" Washer
¾" Locknut
RH Tie Rod End
Tie Rod Assembly
LH Tie Rod End
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
SOFTEK FRONT AXLE ASSEMBLY
STEERTEK AXLE CLAMP GROUP CONSIST OF THE FOLLOWING COMPONENTS:
■ Top axle wrap
■ Bottom axle wrap
■ Top axle wrap liner
■ Bottom axle wrap liner
■ Top pad
■ ¾" Bolts, washers and nylon locknuts
120
FIGURE 9-40
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STEERTEK AXLE REMOVAL
Refer to Figures 9-39 and 9-40 when replacing the components of the STEERTEK axle.
DO NOT USE A TORCH ON CLAMP GROUP BOLTS OR ANY OTHER PART OF THE AIRTEK
SUSPENSION. IF THE CLAMP GROUP BOLTS WILL NOT COME LOOSE WITH AN IMPACT
WRENCH, USE A CUT OFF WHEEL AND CUT THE SHANK OF THE BOLT. THE USE OF A TORCH
CAN CAUSE DAMAGE TO CERTAIN AIRTEK COMPONENTS THAT CAN RESULT IN THE LOSS OF
VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
121
1. Place the vehicle on level floor.
2. Chock the wheels.
3. SOFTEK equipped vehicles — proceed to step 6.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
4. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
5. AIRTEK equipped vehicles — Deflate the air springs by disconnecting the height control valve linkage and lowering the height control valve linkage arm. This will exhaust
the air pressure in the air springs.
6. Raise the frame.
7. Support the vehicle with frame stands.
8. Suspend the front axle with the shocks attached.
9. Remove the front wheels, hubs, brake shoes and backing plate assembly.
10. Disconnect the drag link from the steering arm.
11. SOFTEK equipped vehicles — proceed to step 13.
12. AIRTEK equipped vehicles — Remove lower air spring mounting fasteners for both air
springs at the axle top pad and unseat from the top pad.
13. Support the axle with a floor jack.
THE REPAIR OR RECONDITIONING OF SUSPENSION OR AXLE COMPONENTS IS NOT ALLOWED.
HENDRICKSON ADVISES REPLACING ALL COMPONENTS FOUND TO BE DAMAGED OR OUT OF
SPECIFICATIONS. ALL MAJOR HENDRICKSON COMPONENTS ARE HEAT TREATED AND TEMPERED.
AIRTEK COMPONENTS CANNOT BE BENT, WELDED, HEATED, OR REPAIRED WITHOUT REDUCING
THE STRENGTH OR LIFE OF THE COMPONENT. FAILURE TO FOLLOW THESE GUIDELINES CAN
CAUSE LOSS OF VEHICLE CONTROL, AND POSSIBLE PERSONAL INJURY OR DEATH OR PROPERTY
DAMAGE AND WILL VOID APPLICABLE WARRANTIES.
14. If the vehicle is equipped with the shock absorbers attached to the top axle wrap, it will
be necessary to remove the lower shock mounting locknuts and washers. Remove the
shock absorbers from the lower mounting bolts and push clear of spring assembly.
SERVICE HINT
If a clamp group nut fails to come off bolt, cut half way through the bolt with an abrasive
cut off wheel, taking care not to contact axle beam or other components. Using an impact
wrench, spin the locknut to fracture the bolt and remove.
15. Remove the ¾" clamp group bolts, washers, and locknuts. Discard fasteners.
16. Lower the axle and remove from the vehicle.
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
STEERTEK AXLE (Removed from Chassis)
AXLE DISASSEMBLY
1. Remove the bottom axle wrap and liner from the axle.
2. Strike the top axle wrap with a dead blow mallet at the front and rear on the underside
of the axle wrap to dislodge it from the axle, see Figure 9-41.
122
FIGURE 9-41
3. After removal of the top axle wrap from the axle inspect for cracks or fretting.
4. Remove the tie rod assembly. See Tie Rod disassembly in this section.
REMOVAL OF THE CAP SCREWS WILL ALLOW THE STEERING KNUCKLE TO SEPARATE FROM THE
AXLE. THE BACKBONE MUST BE SUPPORTED BEFORE REMOVAL OF THESE TWO (2) CAP
SCREWS. FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE OR PERSONAL INJURY.
5. Remove the two 5⁄8" socket head cap screws from the steering knuckle assembly.
6. Remove the steering knuckle, thrust bearing, and shims (if equipped).
7. After complete removal of the one side, repeat steps 1-6 for the opposite side of the axle.
8. Inspect the steering kingpin bushings for excessive wear. If worn, replace the kingpin
bushings and seals. See the Kingpin Bushing replacement instructions in this section.
AXLE PRE-ASSEMBLY
1. Install the new upper axle wrap liner on
the axle. Index the liner with the axle's
guide pin, see Figure 9-42.
DO NOT STRIKE THE TOP AXLE WRAP WITH
A HAMMER. DAMAGE TO THE ALUMINUM
AXLE WRAP WILL OCCUR. USE A PLASTIC
DEAD BLOW MALLET WITH CARE WHEN
INSTALLING THE AXLE WRAP.
SECURELY INSTALL THE TOP WRAP TO THE
AXLE. FAILURE TO DO SO CAN CAUSE LOSS
OF CONTROL OF THE VEHICLE, PERSONAL
INJURY OR PROPERTY DAMAGE.
SERVICE HINT
Apply a lubricant (such as an aerosol
silicone) to the outer surface of the plastic
liner to aid in assembly of the top axle wrap.
FIGURE 9-42
Top Axle
Wrap
13.2K/14.6K
Top Axle
Wrap Liner
Top Axle
Wrap-8K/10K
Axle Wrap
Guide Pin
Axle
Bottom Axle
Wrap Liner
Bottom Axle
Wrap
2. Install the top axle wrap, see Axle Wrap
Assembly instructions located in this section. The axle wrap must be aligned with the
guide pin on the axle.
3. At this point in the assembly, do not install anything further on the axle.
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AXLE INSTALLATION
1. Place the new axle on the floor jack and position the axle under the vehicle.
2. Install the axle spacer (if equipped) on the top axle wrap prior to raising the axle into
position.
3. Raise the axle into position, see Figures 9-43 and 9-44. Care must be taken at this
point to ensure that the front leaf spring assemblies' center bolt is aligned correctly in
the top axle wrap.
FIGURE 9-43
AIRTEK 10K
123
AIRTEK 14.6K
Leaf Spring
Assembly
Leaf Spring
Assembly
Rear Shackle
Bracket
Spacer
Dowel Pin
(If equipped)
Spacer (If equipped)
Top Axle Wrap
Top Axle Wrap
FIGURE 9-44
SOFTEK 8K/10K
Rear Shackle
Bracket
SOFTEK 13.2K/14.6K
Leaf Spring
Assembly
Leaf Spring
Assembly
Rear Shackle
Bracket
Dowel Pin
(If equipped)
Spacer
Top Axle
Wrap
Dowel Pin
(If equipped)
Rear Shackle
Bracket
Spacer
Top Axle
Wrap
4. Verify that the galvanized liner is between the leaf springs and the top pad.
5
Install the new bottom axle wrap liners on the bottom axle wraps.
6. Install the bottom axle wraps on the axle.
7. Install the top pad with the directional identification facing correctly on the vehicle, see
Figure 9-45.
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FIGURE 9-45
124
8. Install the new ¾" clamp group bolts, washers and locknuts. Snug the bolts , DO NOT
tighten to the specified torque at this time.
FIGURE 9-46
9. Ensure that the clamp groups are properly aligned and the bolts are seated in the top
pad, and the bottom axle wraps are centered on the top axle wraps, see Figure 9-46.
10. SOFTEK equipped vehicles — proceed to step 13.
PRIOR TO AND DURING DEFLATION AND INFLATION OF THE FRONT AIR SUSPENSION SYSTEM,
ENSURE THAT ALL PERSONNEL AND EQUIPMENT ARE CLEAR FROM UNDER THE VEHICLE AND
AROUND THE SERVICE AREA, FAILURE TO DO SO CAN CAUSE SERIOUS PERSONAL INJURY,
DEATH, OR PROPERTY DAMAGE.
11. See additional Air Spring Cautions and Warnings in the Important Safety Notice Section
of this publication prior to inflating or deflating the suspension system.
12. AIRTEK equipped vehicles:
■
Engage the 10K air springs into the top pad. The bottom of the air spring snaps
into the top pad.
■
Engage the 14.6K air springs into the top pad. Install new lower air spring mounting fasteners and tighten to 20-30 foot pounds torque.
13. Install the lower shock absorber connection (if removed). Install the lower shock fasteners and tighten to vehicle manufacturer's specifications.
14. Install the steering knuckles as per the Steering Knuckle replacement instructions in this
section.
15. Install the tie rod assembly.
16. Install the 7⁄8" hardened washers on the Ackermann arm and the castle nuts. Tighten
the castle nuts to 185 foot pounds, then rotate until the first castle slot lines up with
the cotter pin bore in the tie rod end. Do not back off the nut for cotter pin installation.
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AIRTEK®• SOFTEK® for Blue Bird Buses
17. Install the tie rod end cotter pins.
18. Connect the drag link. Install the castle nut. Tighten the castle nut to
185 foot
pounds, then rotate until the first castle slot lines up with the cotter pin bore in the drag
link. Do not back off the nut for cotter pin installation.
19. Install the drag link cotter pin.
125
20. Install the brake backing plate assemblies.
21. Install the brakes, hubs, and wheels as per manufacturer’s guidelines.
22. Fill the hubs with the proper lubricant (see manufacturer’s guidelines for recommended lubrication specifications).
23. Raise the vehicle and remove the frame stands.
24. Lower the vehicle.
25. SOFTEK equipped vehicles — proceed to step number 27.
26 AIRTEK equipped vehicles — Reconnect the height control valve and air up the system.
FIGURE 9-47
27. Tighten the ¾" clamp group locknuts evenly in 50 foot pounds increments to
285-305 foot pounds torque in the proper sequence to
achieve uniform bolt tension, see Figure 9-47.
28. SOFTEK equipped vehicles — proceed to step number 30.
29 AIRTEK equipped vehicles — Adjust ride height per instructions in the Alignment &
Adjustments Section of this publication.
30. Grease the front steering components as per lubrication guidelines in the Preventive
Maintenance Section of this publication.
31. Remove the wheel chocks.
STEERING KNUCKLE DISASSEMBLY
DISASSEMBLY
See tools needed to remove and install kingpin bushing under the Special Tools Section of
this publication.
The steering knuckle disassembly and assembly includes the Kingpin Preparation and
Measurement and Kingpin Bushing Removal process.
1. Place the vehicle on level floor.
2. Chock the wheels.
3. Raise the frame.
4. Support the vehicle with frame stands.
5. Remove the wheel and hub assembly.
6. Remove the brake components from steering knuckle.
7. Remove the tie rod assembly.
FIGURE 9-48
SERVICE HINT
Lightly tap the side of the Ackermann
arm with a mallet to separate the tie
rod end from the Ackermann arm, see
Figure 9-48.
8. Remove the drag link from the
knuckle if necessary.
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REMOVAL OF THE CAP SCREWS WILL ALLOW THE STEERING KNUCKLE TO SEPARATE FROM
THE AXLE. THE STEERING KNUCKLE MUST BE SUPPORTED BEFORE REMOVAL OF THESE TWO
(2) CAP SCREWS. FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE OR PERSONAL
INJURY.
FIGURE 9-49
126
9. Remove the 2 socket head cap
screws that connect upper
kingpin connection to the steering knuckle, see Figure 9-49.
10. Remove the lower steering
knuckle from the kingpin by
sliding it down the kingpin.
11. Remove the upper steering
knuckle by sliding it up off the
kingpin.
KINGPIN PREPARATION
AND MEASUREMENT
CLEANING GROUND AND POLISHED PARTS
■ Use a cleaning solvent to clean ground or polished parts and surfaces. DO NOT USE
GASOLINE.
■ Do not clean ground or polished parts in a hot solution tank or with water, steam, or
alkaline solutions. These solutions will cause corrosion of the parts.
DRYING THE CLEANED PARTS
■ Parts must be dried immediately after cleaning. Dry the parts with clean paper towels,
clean rags, or compressed air. Do not dry bearings by spinning with compressed air.
Damage to the bearings will result.
PREVENTING CORROSION ON CLEANED PARTS
■ Apply a light coating of oil to all cleaned and dried parts that are going to be reused.
Do not apply oil to the brake lining or the brake drums. If parts are to be stored, apply
an effective rust inhibitor to all surfaces.
TO HELP PREVENT SERIOUS EYE INJURY, ALWAYS WEAR PROPER EYE PROTECTION WHEN
YOU PERFORM VEHICLE MAINTENANCE OR SERVICE.
SOLVENT CLEANERS CAN BE FLAMMABLE, POISONOUS AND CAUSE BURNS. TO HELP AVOID
SERIOUS PERSONAL INJURY, CAREFULLY FOLLOW THE MANUFACTURER’S PRODUCT
INSTRUCTIONS AND GUIDELINES AND THE FOLLOWING PROCEDURES:
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APPENDIX
■
WEAR PROPER EYE PROTECTION.
■
WEAR CLOTHING THAT PROTECTS YOUR SKIN.
■
WORK IN A WELL VENTILATED AREA.
■
DO NOT USE GASOLINE, SOLVENTS OR OTHER MATERIALS THAT CONTAIN GASOLINE
THAT CAN EXPLODE.
■
HOT SOLUTION TANKS OR ALKALINE SOLUTIONS MUST BE USED CORRECTLY. FOLLOW
THE MANUFACTURER’S RECOMMENDED INSTRUCTIONS AND GUIDELINES CAREFULLY
TO HELP PREVENT PERSONAL ACCIDENT OR INJURY.
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AIRTEK®• SOFTEK® for Blue Bird Buses
DO NOT USE HOT SOLUTION TANKS OR WATER AND ALKALINE SOLUTIONS TO CLEAN GROUND
OR POLISHED PARTS. DAMAGE TO THE PARTS WILL RESULT.
THE STEERTEK HAS A UNIQUE AXLE. THE KINGPIN IS CRYOGENICALLY INSTALLED IN THE AXLE.
THE KINGPIN IS A NON-REPLACEABLE COMPONENT OF THE AXLE ASSEMBLY. DO NOT TRY TO
REMOVE THE KINGPIN. DOING SO WILL DAMAGE THE AXLE AND MAY CAUSE LOSS OF VEHICLE
CONTROL, PERSONAL INJURY OR PROPERTY DAMAGE. IF THE KINGPIN SHOWS SIGNS OF
MOVEMENT, CONTACT HENDRICKSON PRODUCT ENGINEERING - TECH SERVICES.
127
1. Prepare and polish the kingpin by removing all grease and excess debris using a fine grit
(220 grit or higher) emery cloth and parts solvent, see Figures 9-50 through 9-53.
FIGURE 9-50
FIGURE 9-51
FIGURE 9-52 KINGPIN BEFORE CLEANING
FIGURE 9-53 KINGPIN AFTER CLEANING
2. Inspect the kingpin for wear or damage. Use a micrometer and measure the upper and
lower kingpin in two locations. Positions must be 90º opposed from each other. If the
kingpin has less than 1.802" diameter, replacement of the axle is necessary, see
Figures 9-54 through 9-57.
Kingpin minimum dimension is 1.802"
FIGURE 9-54
17730-248
FIGURE 9-55
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FIGURE 9-56
FIGURE 9-57
128
KINGPIN BUSHING REMOVAL
1. Remove the retaining ring for the grease cap.
2. A hydraulic shop press with a minimum forcing capacity of 2.5 tons (or use an arbor
press) will be required.
BEFORE APPLYING HYDRAULIC PRESSURE TO ANY TOOLING SET-UP, ALWAYS CHECK TO BE
SURE THE PRESS PLATE, ADAPTERS, AND COMPONENTS BEING WORKED ON ARE
POSITIONED PROPERLY, I.E. “IN LINE” WITH THE RAM. IMPROPER POSITIONING CAN CAUSE
PERSONAL INJURY OR COMPONENT DAMAGE.
BEFORE APPLYING HYDRAULIC PRESSURE TO REMOVE OR INSTALL THE KINGPIN BUSHING,
SUPPORT THE LOWER STEERING KNUCKLE AS SHOWN IN FIGURES 9-58 AND 9-59.
IMPROPER SUPPORT TO THE STEERING KNUCKLES CAN CAUSE COMPONENT DAMAGE.
3. Use the grease cap to press out the kingpin bushing and seal. Remove the grease zerk in
the grease cap or use a hollow driver, (see Figure 9-58) to press out the kingpin bushing.
4. Install the lower steering knuckle upside down in press. Be sure to support the lower
steering knuckle assembly so that it sits in-line with the press, see Figure 9-59.
5. Use the same procedure to remove the kingpin bushing in the upper kingpin connection or the steering arm, see Figures 9-58 through 9-60.
6. Clean the parts and inspect for reassembly, see Figure 9-61.
FIGURE 9-58
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FIGURE 9-59
86
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Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
FIGURE 9-60
FIGURE 9-61
129
STEERING KNUCKLE BORE MEASUREMENT
Complete the following steering knuckle bore inspection and the measurement instructions
prior to installing the kingpin bushing.
1. Measure the upper knuckle bore inside diameter at two locations. Always use an inside
micrometer or a telescoping gauge when taking a knuckle bore measurement. Some
out-of-roundness at the top and bottom of the bore edges is acceptable. Steering
knuckle bore diameter is 1.938" ± 0.003"
2. Measure the upper and lower bore in two positions and at two locations. The two positions must be 90º opposed from each other, see Figures 9-62 through 9-64. If the
average measurement is more than the knuckle bore maximum diameter specification,
replace the knuckle.
FIGURE 9-62
FIGURE 9-63
FIGURE 9-64
KINGPIN BUSHING INSTALLATION
1. A hydraulic shop press with a minimum forcing capacity of 5 tons will be required.
BEFORE APPLYING HYDRAULIC PRESSURE TO ANY TOOLING SET-UP, ALWAYS CHECK TO BE
SURE THE PRESS PLATE, ADAPTERS, AND COMPONENTS BEING WORKED ON ARE
POSITIONED PROPERLY, I.E. “IN LINE” WITH THE RAM. IMPROPER POSITIONING CAN CAUSE
PERSONAL INJURY OR COMPONENT DAMAGE.
2. Install the lower or upper steering knuckle in the press.
3. Install the kingpin bushing from the machined side (axle side) of the lower steering
knuckle using a bushing driver, (see driver specifications in the Special Tools Section of
this publication). Press in bushing to a depth of no less than 15/64" (0.236") or 6 millimeters and no more than 5/16" (0.32") or 8 millimeters, see Figures 9-65 and 9-67.
4. Following this procedure it is necessary to ream the kingpin bushings to fit the kingpins, (see Kingpin Bushing Reaming Instructions).
17730-248
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AIRTEK®• SOFTEK® for Blue Bird Buses
FIGURE 9-65
FIGURE 9-66
FIGURE 9-67
130
KINGPIN BUSHING REAMING
REAM THE KINGPIN BUSHINGS WITH AN ADJUSTABLE STRAIGHT FLUTE REAMER. (SEE
SPECIAL TOOLS SECTION OF THIS PUBLICATION) DO NOT HONE OR BURNISH THE KINGPIN
BUSHINGS. HONING OR BURNISHING WILL DAMAGE THE BUSHINGS AND VOID WARRANTY.
WHEN INSTALLING STEERING KNUCKLE COMPONENTS IN A VISE IT IS NECESSARY TO
PROTECT THE MACHINED SURFACES FROM GOUGES OR MARRING BY USING BRASS JAWS.
FAILURE TO DO SO CAN CAUSE PREMATURE PART DAMAGE, DAMAGE TO THE STEERING
KNUCKLE COMPONENTS, LOSS OF WARRANTY, LOSS OF VEHICLE CONTROL, CAUSING
PERSONAL INJURY OR PROPERTY DAMAGE.
1. Install the lower steering knuckle assembly in a vise with brass jaws.
SERVICE HINT
It is acceptable to mount the knuckle components in a vise either vertically or horizontally
when performing the reaming procedure.
2. Install the reamer into the lower steering knuckle until the blades touch the kingpin
bushing.
3. Rotate the reamer with light downward pressure. Rotate the reamer smoothly. Do not
apply too much pressure, see Figures 9-68 and 9-69.
FIGURE 9-68 Lower Steering Knuckle in Vise
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APPENDIX
88
FIGURE 9-69 Upper Steering Knuckle in Vise
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
4. Slide the reamer out of the bottom of the steering knuckle assembly. If it is necessary
to remove the reamer from the top, rotate the reamer opposite of cutting rotation.
5. Clean and remove all kingpin bushing material from the steering knuckle assembly.
Take special attention to remove material from the grease channels and dimples.
6. Clean the 5/8" brake backing plate bolts with a wire wheel and run a tap through the
threads of the lower steering knuckle assembly and then flush out with brake cleaner
and dry with compressed air.
131
PRIOR TO INSTALLATION ENSURE THAT ALL RESIDUAL LOCTITE® MATERIAL IS REMOVED FROM
THE MOUNTING BOLTS AND THE THREAD BORES IN THE UPPER STEERING KNUCKLES, AND
NEW LOCTITE 277 OR EQUIVALENT IS APPLIED TO HELP ENSURE THAT THE BOLTS SUSTAIN
THE PROPER TORQUE REQUIREMENT. FAILURE TO DO SO CAN CAUSE LOSS OF VEHICLE
CONTROL RESULTING IN PERSONAL INJURY OR PROPERTY DAMAGE.
NOTE
The Hendrickson Genuine part, socket head cap screw comes with a pre-applied loctite
compound.
7. Install the upper and lower steering knuckle on the kingpin.
8. Check for the proper fit by rotating the knuckle assembly back and forth to verify there
is no binding on the kingpin, see Figures 9-70 and 9-71.
9. If the bushing is too tight repeat steps 1 through 8 until the proper clearance is
achieved.
NOTE
Bushing size is to be 0.001" larger than the kingpin size.
FIGURE 9-70
FIGURE 9-71
KINGPIN SEAL INSTALLATION
1. Place the steering knuckle assembly in a vise with brass jaws or place on a suitable workbench. The steering knuckle will have the machined surface facing up (axle side up).
2. Lay the kingpin seal into the bore of the steering knuckle. The seal lip should face outward or toward the axle.
3. Use a bushing driver tool and press seal firmly into the steering knuckle assembly.
4. Install the kingpin seal until it makes contact with the kingpin bushing, see Figures
9-72 and 9-73.
17730-248
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AIRTEK®• SOFTEK® for Blue Bird Buses
FIGURES 9-72 AND 9-73
132
STEERING KNUCKLE ASSEMBLY
ASSEMBLY
After replacement of the kingpin bushings it is necessary to re-assemble the steering knuckle assemblies. The STEERTEK axle is equipped with two different thrust bearings installed.
The composite thrust bearing is installed on the left side of the axle. The roller bearing is
installed on the right side of the axle, see Figures 9-74 and 9-75, for right hand drive axle
configuration the thrust bearings will be the opposite. Do not substitute aftermarket components when servicing.
1. Install the thrust bearing on the lower kingpin with the seal facing up toward axle (the
black seal will designate the top side). The composite thrust bearing is installed on the
left side of the axle. The roller bearing is installed on the right side of the axle, see
Figures 9-74 and 9-75. For right hand drive axle configuration the thrust bearings will
be the opposite.
2. Install the shim on the upper kingpin.
3. Pack the bushing dimples on the upper and lower steering knuckles with multi purpose
Lithium based grease (NLGI Grade 2) before installation, see Figures 9-74 and 9-75.
FIGURE 9-74
FIGURE 9-75
4. Install the upper steering knuckle on the upper arm kingpin.
5. Install the lower steering knuckle on the lower kingpin and install the old socket head
cap screws loose into the top two threaded holes.
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AIRTEK®• SOFTEK® for Blue Bird Buses
SERVICE HINT
The easiest way to achieve this is with the grease caps not installed in the knuckle
assemblies. This eliminates back pressure. The assembly can then freely slide up and
down on the kingpin. If the grease caps are still installed, remove the grease zerks to avoid
creating back pressure. Grease zerks will be re-installed at the end of the procedure.
6. Install a bottle jack under the lower knuckle and slightly raise the knuckle until it is
possible to thread in the (3) brake backing plate bolts by hand. These are for guide
purposes only.
133
7. Snug the two socket head cap screws.
8. Lower the bottle jack so that all the vertical clearance is on the underside of the axle.
9. Affix a magnetic base dial indicator on the axle and place the tip of the dial indicator
on top of the knuckle assembly, see Figure 9-76.
10. Zero the dial indicator.
FIGURE 9-76
11. Raise the bottle jack until there is no
clearance between the knuckle
assembly and the bottom of the
axle, slightly lifting the axle.
12. Check the reading on the dial indicator. The specification for vertical
travel on the steering knuckle during
assembly is 0.008" to 0.011".
13. If the clearance is above 0.011",
loosen the socket head cap screws
and push down on the knuckle
assembly until the proper vertical
clearance is achieved. Add (0.005") shim if necessary.
14. If the clearance is below the 0.008", loosen the two socket head cap screws and pull
up on the knuckle assembly until the proper vertical clearance is achieved. If the 0.008"
minimum clearance is unattainable it may be necessary to remove a 0.005" shim.
NOTE
The
Hendrickson Genuine part, socket head cap screw comes with a pre-applied loctite
compound.
PRIOR TO INSTALLATION ENSURE THAT ALL RESIDUAL LOCTITE MATERIAL IS REMOVED FROM
THE MOUNTING BOLTS AND THE THREAD BORES IN THE UPPER STEERING KNUCKLE, AND
NEW LOCTITE 277 OR EQUIVALENT IS APPLIED TO HELP ENSURE THAT THE BOLTS SUSTAIN
THE PROPER TORQUE REQUIREMENT. FAILURE TO DO SO CAN CAUSE LOSS OF VEHICLE
CONTROL RESULTING IN PERSONAL INJURY OR PROPERTY DAMAGE.
15. Remove one old socket head cap screw and replace with new socket head cap screw.
16. Remove second socket head cap screw and replace with new socket head cap screw.
Tighten both socket head cap screws to 175-200 foot pounds torque.
17. Recheck the vertical clearance with the dial indicator or a 0.010" feeler gauge, see
Figure 9-76.
18. Remove the brake spider bolts, they should thread out freely.
19. Remove the bottle jack and continue assembling the wheel ends.
IMPORTANT NOTE
17730-248
Loctite applied to the three brake spider bolts is a critical procedure to ensure that these
bolts sustain the torque requirement of Steering knuckle assembly.
91
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
20. Apply loctite to the three brake spider bolts prior to installation into the brake spider.
Tighten bolts to 175-200 foot pounds torque.
DO NOT GREASE KNUCKLES WITHOUT THE BRAKE SPIDER INSTALLED AND TIGHTENED TO
PROPER TORQUE. FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE RESULTING IN
FAILURE AND LOSS OF VEHICLE CONTROL, POSSIBLY CAUSING PERSONAL INJURY OR
PROPERTY DAMAGE.
134
21. Install the tie rod end into the lower steering knuckle arm.
22. Tighten the castle nuts to
185 foot pounds torque then rotate the castle nut to the
next castle slot and install cotter pin.
23. Install the drag link into the steering arm and tighten to the vehicle manufacturer’s
specifications.
24. Install new o-rings on the grease caps and lubricate o-rings with grease.
25. Install grease caps and new retaining rings.
26. Install brakes, drums, wheels and tires.
27. Remove jack and safety stands.
28. Grease steering knuckles with the vehicle on the floor.
29. Remove wheel chocks.
TIE ROD END AND CROSS TUBE
NOTE:
Hendrickson supplies different tie rod configurations. Prior to ordering find the part number
on the tie rod tube. For additional information see Technical Bulletin SEU-0223 or contact
Hendrickson Sales Engineering.
DISASSEMBLY
1. Chock the wheels.
2. Position the steer axle tires straight ahead.
3. Remove the cotter pin and castle nut.
4. Lightly tap the side of the Ackermann arm to loosen the tie rod end from the Ackermann
arm, see Figure 9-77.
FIGURE 9-77
5. Repeat to steps 3 and 4 to remove
the other tie rod end.
6. Remove the cross tube and tie rod
ends from the vehicle.
7. Mount the cross tube in a soft
jaw vice.
8. Remove the hardware from the clamp on the cross tube.
9. Count the exposed threads on the tie rod end being replaced.
10. Remove the tie rod end from the cross tube.
DO NOT HEAT THE CROSS TUBE WITH A TORCH TO FACILITATE THE REMOVAL OF THE TIE ROD
END. THE USE OF SUCH HEAT CAN ADVERSELY AFFECT THE STRENGTH OF THE CROSS TUBE.
A COMPONENT DAMAGED IN THIS MANNER WILL RESULT IN LOSS OF WARRANTY, AND CAN
RESULT IN THE AND LOSS OF VEHICLE CONTROL, AND POSSIBLE PERSONAL INJURY OR
PROPERTY DAMAGE.
11. If the opposing tie rod end is being replaced repeat steps 8 through 10.
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AIRTEK®• SOFTEK® for Blue Bird Buses
12. Inspect the cross tube for dents, cracks, or thread damage. Replace the cross tube if
needed.
ASSEMBLY
1. Lubricate the new tie rod end threads with Anti-Seize.
NOTE
When installing the cross tube the thread direction of the tie rod ends are as follows:
■
A right hand threaded tie rod end will be installed into the right side Ackermann arm.
■
A left hand threaded tie rod end will be installed into the left side Ackermann arm.
135
2. Install the new tie rod end into the cross tube, leaving the same amount of threads
exposed that were counted on the failed tie rod end prior to removal.
THE THREADED PORTION OF THE TIE ROD END MUST EXTEND PAST THE SLOTS INTO THE TIE
ROD CROSS TUBE, SEE FIGURE 9-78. FAILURE TO DO SO CAN CAUSE COMPONENT DAMAGE,
LOSS OF VEHICLE CONTROL AND POSSIBLE PERSONAL INJURY OR PROPERTY DAMAGE.
FIGURE 9-78
3. Replace the opposing tie rod end if necessary by repeating steps 2 and 3.
4. If replacing opposing tie rod end, it is critical that the cross tube will rotate in the opposing tie rod end.
DO NOT HEAT THE CROSS TUBE WITH A TORCH TO ROTATE THE CROSS TUBE IN THE TIE ROD
END. THE USE OF SUCH HEAT CAN ADVERSELY AFFECT THE STRENGTH OF THE CROSS TUBE.
A COMPONENT DAMAGED IN THIS MANNER WILL RESULT IN LOSS OF WARRANTY, AND CAN
RESULT IN THE LOSS OF VEHICLE CONTROL, AND POSSIBLE LOWER STEERING KNUCKLE
PERSONAL INJURY OR PROPERTY DAMAGE.
5. Install the cross tube into the Ackermann arms.
6. Tighten the castle nuts to
185 foot pounds torque then rotate the castle nut to the
next castle slot and install cotter pin.
7. Grease tie rod ends, see Lubrication Chart for required lubricant in the Preventive
Maintenance Section of this publication.
8. Set the toe, (see the Toe Adjustment Procedure in the Alignment & Adjustments Section
of this publication).
9. Remove the wheel chocks.
17730-248
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AIRTEK®• SOFTEK® for Blue Bird Buses
SECTION 10
Plumbing Diagrams
AIRTEK SINGLE HEIGHT CONTROL VALVE – 10K
136
When replacing or installing nylon air line tubing into quick-connect fittings it is critical that
the end of the air line is cut square. Improper cut of the end of the air line tubing can cause
the air line to seat improperly in the quick connect fitting causing air leakage.
Plumbing Diagrams
L
1
APPENDIX
94
17730-248
Front axle & suspension
AIRTEK®• SOFTEK® for Blue Bird Buses
AIRTEK DUAL HEIGHT CONTROL VALVES – 14.6K
When replacing or installing nylon air line tubing into quick-connect fittings it is critical that
the end of the air line is cut square. Improper cut of the end of the air line tubing can cause
the air line to seat improperly in the quick connect fitting causing air leakage.
137
¼" Nylon Air Line
S.A.E., D.O.T. compliant
Use convoluted tubing
over all nylon air lines
FRO
NT
“In” Port
Pressure
Protection
Valve
¾" Nylon Air Line
S.A.E., D.O.T. compliant
Use convoluted tubing
over all nylon air lines
To Air Spring
C2
C1
“Exhaust”
Port
17730-248
To Air Spring
95
Plumbing Diagrams
1
APPENDIX
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SERVICE MANUAL
AIRTEK®• SOFTEK® for Blue Bird Buses
138
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Front axle & suspension
Appendix
Reference Material
This technical publication covers Hendrickson Truck Suspension’s recommended
procedures for our parts/products. Other components play a major role in overall
performance and Hendrickson recommends you follow the specific vehicle manufacturer’s recommendation for care and maintenance. Some recommended procedures
have been developed by The Technology & Maintenance Council (TMC) and
Hendrickson supports these recommendations. We have compiled a list of these
below.
139
TMC
To obtain copies of the following RP’s, video’s, or charts, contact TMC at:
TMC/ATA
2200 Mill Road
Alexandria, VA 22314
Phone: 703-838-1763
website: tmc.truckline.com
online ordering: www.truckline.com/store
Important References
TMC RP 214B
Tire/Wheel End Balance and Runout
TMC RP 216
Radial Tire Conditions Analysis Guide
TMC RP 219A
Radial Tire Wear Conditions and Causes
TMC RP 222A
User’s Guide To Wheels and Rims
TMC RP 230
Tire Test Procedures for Tread wear, Serviceability, and
Fuel Economy
TMC RP 514
Pre-Alignment Inspection
TMC RP 618
Wheel Bearing Adjustment Procedure
TMC RP 620B
Front End Alignment Steering Geometry
TMC RP 708A
Trailer Axle Alignment
TMC RP 642
Guidelines For Total Vehicle Alignment
TMC RP 644
Wheel End Conditions Analysis Guide
TMC RP 645
Tie Rod End Inspection and Maintenance Procedure
Video’s
TMC T0326
Wheel End Maintenance
TMC T0372
Tire Pre-Trip Inspection Guidelines
Other
Wheel bearing Adjustment Procedure Wall Chart
17730–248
TMC T0400
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Appendix
AIRTEK/SOFTEK
TROUBLESHOOTING GUIDE
CONDITION
140
Worn or damaged kingpins and
kingpin bushings
Vibration or shimmy of front axle
during operation
POSSIBLE CAUSE
CORRECTION
Dirt in system– contaminated lubricant
Polish and inspect kingpin, replace bushing
and seals, then follow specified lubrication
procedures
Incorrect lubricant
Lubricate axle with specified lubricant
Axle not lubricated at scheduled frequency
Lubricant axle at scheduled frequency
Incorrect lubrication procedures
Use correct lubrication procedures
Lubrication interval not compatible with
operating conditions
Change lubrication interval to match
operating conditions
Worn or missing seals
Replace worn or missing seals
Caster out of specification
Set proper ride height then adjust caster to
specification
Wheels and/or tires out of balance
Balance or replace wheels and/or tires
Worn shock absorbers
Replace shock absorbers
Worn thrust washers (if equipped) and rear
hanger clamps
Replace thrust washers (if equipped) and
rear hanger clamps
Broken engine mount
Replace engine mount
Wheel bearing adjustment
Adjust wheel bearing to the vehicle
manufacturers specifications.
Tires have incorrect air pressure
Adjust tire pressure to manufacturer’s
specification.
Tires out of balance
Balance or replace tires
Incorrect tandem axle alignment
Align tandem axles
Incorrect toe setting
Adjust toe-in to manufacturer’s specification
Excessive wear on tires or uneven
Incorrect steering arm geometry
tire tread wear
Worn kingpin bushings
Vehicle is hard to steer
17730–248
A-98
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APPENDIX
Repair steering system as necessary
Replace kingpin bushings
Excessive wheel bearing end play
Check specified wheel nut torque, replace
worn or damaged wheel bearings
Wheel bearing adjustment
Adjust wheel bearing to the vehicle
manufacturers specifications.
Low pressure in the power steering system
Repair power steering system
Steering linkage needs lubrication
Lubricate steering linkage
Steering knuckles are binding
Check vertical clearance
Incorrect steering ar geometry
Repair steering system as necessary
Caster out of specification
Set proper ride height then adjust caster to
specification
Tie rod ends hard to move
Replace tie rod ends
Worn thrust bearing
Replace thrust bearing
Steering gear box internal problem
Perform steering gear trouble shooting
procedures per steering gear manufacturing
guidelines.
Appendix
Front axle & suspension
AIRTEK/SOFTEK
TROUBLESHOOTING GUIDE (CONTINUED)
POSSIBLE CAUSE
CORRECTION
Tie rod ends need lubrication
Lubricate tie rod end. Make sure lubrication
schedule is followed.
Tie rod ends are worn and require
replacement
Severe operating conditions
Worn or broken steering ball stud
Suspension has harsh or bumpy
ride
Restricted steering radius
Vehicle leans
Vehicle wanders
Increase frequency of inspection and
lubrication intervals
Damaged boot on tie rod end
Replace tie rod end
Pump/gear relief valve pressure setting
exceeds system specifications
Adjust power steering system to
manufacturer's specified pressure
Bent or broken cross tube, tie rod
end ball stud or tie rod end
Steering gear poppets improperly set or
malfunctioning
NOTE:
Axle stops improperly set
Damaged components require
replacement
Severe duty cycle service
141
Check for proper operation or adjust poppets
to OEM specifications
Set axle stops to OEM specifications
Increase frequency of inspection and
lubrication intervals
Drag link fasteners lightened past specified
torque
Tighten drag link fasteners to the specified
torque
Lack of lubrication or incorrect lubricant
Lubricate linkage with specified lubricant
Power steering stops out of adjustment
Adjust steering stops to OEM specifications
Air spring not inflated
Check air supply to air spring, repair as
necessary
Air spring ride height out of specification
Adjust ride height to proper specification
Broken or worn leaf spring
Replace leaf spring
Front suspension overloaded
Redistribute steer axle load
Steering stops not adjusted correctly
Adjust steering stops to achieve correct
wheel cut
Ride height incorrect
Adjust ride height to specification
Air spring(s) are not inflated
Repair source of air pressure loss
Suspension is not torqued correctly at
installation
Perform spring eye re-torque procedure.
See Torque Specification Section of this
publication
Leaf spring broken
Replace leaf spring
Excessive weight bias
Contact the vehicle manufacturer or
Hendrickson Tech Services
Caster out of specifications
Set proper ride height then adjust caster to
specification
Incorrect toe setting
Adjust toe to specification
Fifth wheel not greased
Grease fifth wheel
Air in the power steering system
Remove air form the power steering systems
Rear ride height out of adjustment
Adjust ride height to specification
Front ride height out of adjustment
Adjust ride height to specification
17730–248
CONDITION
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Appendix
AIRTEK for Blue Bird Vision Buses - 10K Capacity
Hendrickson Recommended Torque Values Provided in Foot Pounds
142
17730–248
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Front axle & suspension
Appendix
AIRTEK for Blue Bird Vision Buses – 10K
HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS
NO.
COMPONENT
QTY.
SIZE
TORQUE VALUE
(in foot pounds)
1
Front Frame Hanger to Front Leaf Spring Eye
2
M20
*290-310
2
Rear Shackle Bracket to Shackle Plate
2
M20
*290-310
3
Rear Shackle Bracket to Spring Eye
2
M20
*290-310
4
Air Spring
2
Self-Locking
Snap Fit
5
Height Control Valve to Frame
2
¼"
8-10
6
HCV Linkage to HCV Arm
2
5 16
/ "
10-12
7
HCV Linkage to Top Pad
2
5 16
/ "
10-12
8
HCV Linkage Grommet to HCV Arm
1
Grommet
Push In
9
HCV Linkage Grommet to Top Pad
1
Grommet
Push In
10
Spring Center Aligning Dowel Pin (Flat Floor Bus)
2
¾"
***Loose Fit
11
Axle Wrap Liners for Clamp Group
2
Formed
Snap Fit
143
DO NOT ASSEMBLE CLAMP GROUP WITHOUT AXLE WRAP LINERS. FAILURE TO DO SO CAN CAUSE
LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE OR PERSONAL INJURY.
12
Clamp Group Hardware
8
¾"
285-305
ENSURE CLAMP GROUP IS ALIGNED PROPERLY PRIOR TO TIGHTENING HARDWARE. FAILURE TO DO
SO CAN CAUSE LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE OR PERSONAL INJURY.
13
Knuckle Attachment Bolt (Socket Head Cap Screw)
4
14
Knuckle / Axle Wheel Stop Bolt
2
15
Tie Rod Tube to Tie Rod Ends
2
16
Tie Rod Ends to Lower Steering Knuckle
2
17
Shocks Eye Bolts
2
/"
175-200
/ " Jam Nut
40-60
/"
60-75
/ " Castle Nut
**185
¾"
*125-135
58
58
58
78
• All hardware ¼" and greater is Grade 8 with no additional lubrication.
Frame mount hardware in most cases are Huck style fasteners supplied by the OEM.
NOTE:
* All hardware information in gray in the matrix denotes recommended torques for fasteners originally supplied by the vehicle
manufacturer. If Hendrickson supplied fasteners are used, tighten to Hendrickson torque values, if non Hendrickson fasteners are used,
follow torque specifications listed in the vehicle manufacturer’s service manual. Hendrickson is not responsible for maintaining vehicle
manufacturer’s torque values.
** Torque to 185 foot lbs., advance nut to next hex face to install cotter pin. Do not back off nut for cotter pin installation.
*** Denote items not shown on illustration.
Blue Bird
RIDE HEIGHT
COMFORT AIR
SHOCK ABSORBER
LENGTH
From the bottom of the
At ride height with a
frame to the center of axle tolerance of ¼"
Vision 10K
12½"
18 9/16"
RIDE HEIGHT
17730–248
AIRTEK
MODEL
SHOCK ABSORBER
LENGTH
From the bottom of the
At ride height with a
frame to the bottom of the tolerance of ¼"
main support member.
47/8"
22¾"
A-101
1
APPENDIX
L
SERVICE MANUAL
Appendix
SOFTEK for Blue Bird Vision Buses - 8K/10K Capacity
Hendrickson Recommended Torque Values Provided in Foot Pounds
1.
*290-310
144
1.
*290-310
12.
Press Fit
12.
Press Fit
11.
*125-135
11.
*125-135
11.
*125-135
2.
*290-310
2. & 3.
*290-310
3.
*290-310
5.
Snap Fit
5.
Snap Fit
11.
*125-135
7.
175-200
8.
40-60
10.
**185
5.
Snap Fit
7.
175-200
10.
**185
8.
40-60
6.
285-305
6.
285-305
9.
60-75
9.
60-75
For vehicles built
prior to 11/06
17730–248
A-102
L
1
APPENDIX
2. & 3.
*290-310
Front axle & suspension
Appendix
SOFTEK for Blue Bird Vision Buses – 8K/10K
HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS
NO.
COMPONENT
QTY.
SIZE
TORQUE VALUE
(in foot pounds)
1
Front Frame Hanger to Front Leaf Spring Eye
2
M20
*290-310
2
Rear Shackle Bracket to Shackle Plate
2
M20
*290-310
3
Rear Shackle Bracket to Spring Eye
2
M20
*290-310
4
Spring Center Aligning Dowel Pin (Flat Floor Bus)
2
¾"
***Loose Fit
5
Axle Wrap Liners for Clamp Group
2
Formed
Snap Fit
145
DO NOT ASSEMBLE CLAMP GROUP WITHOUT AXLE WRAP LINERS. FAILURE TO DO SO CAN CAUSE
LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE OR PERSONAL INJURY.
6
Clamp Group Hardware
8
¾"
285-305
ENSURE CLAMP GROUP IS ALIGNED PROPERLY PRIOR TO TIGHTENING HARDWARE. FAILURE TO DO
SO CAN CAUSE LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE OR PERSONAL INJURY.
7
Knuckle Attachment Bolt (Socket Head Cap Screw)
4
8
Knuckle / Axle Wheel Stop Bolt
2
/"
175-200
/ " Jam Nut
40-60
58
58
/"
60-75
/ " Castle Nut
**185
4
¾"
*125-135
2
—
Press Fit
9
Tie Rod Tube to Tie Rod Ends
2
10
Tie Rod Ends to Lower Steering Knuckle
2
11
Shocks Eye Bolts
12
Rubber Axle Stop
58
78
• All hardware ¼" and greater is Grade 8 with no additional lubrication.
Frame mount hardware in most cases are Huck style fasteners supplied by the OEM.
NOTE:
* All hardware information in gray in the matrix denotes recommended torques for fasteners originally supplied by the vehicle
manufacturer. If Hendrickson supplied fasteners are used, tighten to Hendrickson torque values, if non Hendrickson fasteners are used,
follow torque specifications listed in the vehicle manufacturer’s service manual. Hendrickson is not responsible for maintaining vehicle
manufacturer’s torque values.
** Torque to 185 foot lbs., advance nut to next hex face to install cotter pin. Do not back off nut for cotter pin installation.
17730–248
*** Denote items not shown on illustration.
A-103
1
APPENDIX
L
SERVICE MANUAL
Appendix
AIRTEK for Blue Bird All American Buses - 14.6K Capacity
Hendrickson Recommended Torque Values Provided in Foot Pounds
146
17730–248
A-104
L
1
APPENDIX
Front axle & suspension
Appendix
AIRTEK for Blue Bird All American Buses – 14.6K
HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS
NO.
COMPONENT
QTY.
SIZE
TORQUE VALUE
(in foot pounds)
(in Nm)
1
Front Frame Hanger to Front Leaf Spring Eye
2
M20
*290-310
*393-420
2
Rear Shackle Bracket to Shackle Plate
2
M20
*290-310
*393-420
3
Rear Shackle Bracket to Spring Eye
2
M20
*290-310
*393-420
4
Air Spring to Air Spring Bracket
2
¾"
*20-30
*27-41
5
Air Spring to Top Pad
2
½"
20-30
27-41
6
Height Control Valve to Air Spring Bracket
2
¼"
8-10
11-14
7
HCV Linkage to HCV Arm
2
5 16
/ "
10-12
14-16
8
HCV Linkage to Top Pad
2
5 16
/ "
10-12
14-16
9
HCV Linkage Grommet to HCV Arm
1
Grommet
Push In
10
HCV Linkage Grommet to Top Pad
1
Grommet
Push In
11
Spring Center Aligning Dowel Pin (Flat Floor Bus)
2
¾"
Loose Fit
12
Axle Wrap Liners for Clamp Group
2
Formed
Snap Fit
147
DO NOT ASSEMBLE CLAMP GROUP WITHOUT AXLE WRAP LINERS. FAILURE TO DO SO CAN CAUSE
LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE OR PERSONAL INJURY.
13
Clamp Group Hardware
8
¾"
285-305
386-414
ENSURE CLAMP GROUP IS ALIGNED PROPERLY PRIOR TO TIGHTENING HARDWARE. FAILURE TO
DO SO CAN CAUSE LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE OR PERSONAL INJURY.
14
Knuckle Attachment Bolt (Socket Head Cap Screw)
4
15
Knuckle / Axle Wheel Stop Bolt
2
16
Tie Rod Tube to Tie Rod Ends
2
17
Tie Rod Ends to Lower Steering Knuckle
2
18
Shocks Eye Bolts
2
/"
175-200
237-271
/ " Jam Nut
40-60
54-81
58
58
/"
60-75
81-102
/ " Castle Nut
**185
**251
¾"
*125-135
*169-183
58
78
• All hardware ¼" and greater is Grade 8 with no additional lubrication.
Frame mount hardware in most cases are Huck style fasteners supplied by the OEM.
NOTE:
* All hardware information in gray in the matrix denotes recommended torques for fasteners originally supplied by the vehicle
manufacturer. If Hendrickson supplied fasteners are used, tighten to Hendrickson torque values, if non Hendrickson fasteners are used,
follow torque specifications listed in the vehicle manufacturer’s service manual. Hendrickson is not responsible for maintaining vehicle
manufacturer’s torque values.
** Torque to 185 foot pounds (251 Nm), advance nut to next hex face to install cotter pin. Do not back off nut for cotter pin installation.
Blue Bird
RIDE HEIGHT
COMFORT AIR
SHOCK ABSORBER
LENGTH
From the bottom of the
At ride height with a
frame to the center of axle tolerance of ¼"
All American
Front Engine Model
All American
Rear Engine Model
147⁄8"
17¼"
147⁄8"
1715⁄32"
RIDE HEIGHT
SHOCK ABSORBER
LENGTH
17730–248
AIRTEK
MODEL
From the bottom of the
At ride height with a
frame to the bottom of the tolerance of ¼"
main support member.
47⁄8"
22¾"
A-105
1
APPENDIX
L
SERVICE MANUAL
Appendix
SOFTEK for Blue Bird All American Buses - 13.2K/14.6K Capacity
Hendrickson Recommended Torque Values Provided in Foot Pounds
148
17730–248
A-106
L
1
APPENDIX
Front axle & suspension
Appendix
SOFTEK for Blue Bird All American Buses – 13.2K/14.6K
HENDRICKSON RECOMMENDED TORQUE SPECIFICATIONS
NO.
COMPONENT
QTY.
SIZE
TORQUE VALUE
(in foot pounds)
(in Nm)
1
Front Frame Hanger to Front Leaf Spring Eye
2
M20
*290-310
*393-420
2
Rear Shackle Bracket to Shackle Plate
2
M20
*290-310
*393-420
3
Rear Shackle Bracket to Spring Eye
2
M20
*290-310
*393-420
4
Spring Center Aligning Dowel Pin (Flat Floor Bus)
2
¾"
Loose Fit
5
Axle Wrap Liners for Clamp Group
2
Formed
Snap Fit
149
DO NOT ASSEMBLE CLAMP GROUP WITHOUT AXLE WRAP LINERS. FAILURE TO DO SO CAN CAUSE
LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE OR PERSONAL INJURY.
6
Clamp Group Hardware
8
¾"
285-305
386-414
ENSURE CLAMP GROUP IS ALIGNED PROPERLY PRIOR TO TIGHTENING HARDWARE. FAILURE TO DO
SO CAN CAUSE LOSS OF VEHICLE CONTROL, PROPERTY DAMAGE OR PERSONAL INJURY.
7
Knuckle Attachment Bolt (Socket Head Cap Screw)
4
8
Knuckle / Axle Wheel Stop Bolt
2
9
Tie Rod Tube to Tie Rod Ends
2
/"
175-200
237-271
/ " Jam Nut
40-60
54-81
/"
60-75
81-102
/ " Castle Nut
**185
**251
*125-135
58
58
58
10 Tie Rod Ends to Lower Steering Knuckle
2
11 Shocks Eye Bolts
4
¾"
12 Rubber Axle Stop
2
—
78
*169-183
Press Fit
• All hardware ¼" and greater is Grade 8 with no additional lubrication.
Frame mount hardware in most cases are Huck style fasteners supplied by the OEM.
NOTE:
* All hardware information in gray in the matrix denotes recommended torques for fasteners originally supplied by the vehicle
manufacturer. If Hendrickson supplied fasteners are used, tighten to Hendrickson torque values, if non Hendrickson fasteners are used,
follow torque specifications listed in the vehicle manufacturer’s service manual. Hendrickson is not responsible for maintaining vehicle
manufacturer’s torque values.
17730–248
** Torque to 185 foot pounds (251 Nm), advance nut to next hex face to install cotter pin. Do not back off nut for cotter pin installation.
A-107
1
APPENDIX
L
SERVICE MANUAL
Appendix
AIRTEK for Blue Bird Buses
FRONT AIR MODULE SUSPENSION ALIGNMENT SPECIFICATION
CAMBER1
150
RANGE
DESIGN SPECIFICATION
MINIMUM
MAXIMUM
0.00º ± 1.0º
-1.0º
+1.0º
RIGHT
- 0.25º ± 1.0º
-1.25º
+0.75º
CROSS
Max 2.0º
—
—
LEFT
CAMBER NOTES:
1
The camber angle is not adjustable. Do not bend axle or otherwise try to adjust camber. If found out of specification, notify
Hendrickson Tech Services for further information.
RANGE
CASTER1,2
DESIGN SPECIFICATION
LEFT
RIGHT
CROSS
3
10K
14.6K
MINIMUM
MAXIMUM
MINIMUM
MAXIMUM
4.1º ± 1º
+3.1º
+5.1º
+3.1º
+5.1º
4.1º ± 1º
+3.1º
+5.1º
+3.1º
+5.1º
Max 1.0º
—
—
—
—
CASTER NOTES:
1
Caster is determined with the vehicle at specified ride height for air suspension or at rated load for mechanical suspension
systems. It is critical that the vehicle front and rear ride height is within specifications prior to performing a caster
measurement or adjustment. See Hendrickson ride height specifications and procedure.
2
In most cases actual vehicle caster is defined with the frame rails at zero slope. Refer to the vehicle manufacturer’s
specifications for correct frame rail slope. (Both the alignment surface and the vehicle’s frame rails should be level during
execution of alignment procedures). For vehicles with a positive frame rake (higher in rear) add the frame slope (in
degrees) to the caster reading to determine true vehicle caster.
3
The cross caster angle is not adjustable – Do not bend axle or otherwise try to adjust cross caster. If found out of
specifications notify Hendrickson Tech Services for further information. Changes to caster can be attained by using caster
shims as provided by the vehicle manufacturer or chassis and body manufacturer. Caster shims must match, side to side,
to reduce uneven loading to the suspension components. The use of two different angle caster shims will not correct
cross caster.
4
Example of caster adjustment: 2.5º RH/3º LH, would require one, 1.0 shim on each side to increase caster and achieve
3.5° RH/4.0° LH, which is in specification. Do not attempt to use uneven shims.
Hendrickson recommends following TMC2 practices:
DESIGN SPECIFICATION¹
TOTAL TOE
2
/ " ± / " (0.06" ± 0.03")
1 16
1 32
RANGE
MINIMUM
/ " (0.03")
1 32
MAXIMUM
/ " (0.09")
3 32
TOE-IN NOTES:
17730–248
A-108
L
1
APPENDIX
1
Toe-in is to be set and adjusted in the normal vehicle unladed configuration. Actual vehicle curb weight on the ground. Toe
should be checked at the tires front and rear tread center, at a distance above ground equal to the tire's rolling radius.
2
In most instances total toe is set by the vehicle manufacturer or body builder. Consult the vehicle manufacturer for
specifications.
Front axle & suspension
Appendix
SOFTEK for Blue Bird Buses
FRONT AIR MODULE SUSPENSION ALIGNMENT SPECIFICATION
CAMBER1
RANGE
DESIGN SPECIFICATION
0.00º ± 1.0º
MINIMUM
-1.0º
MAXIMUM
+1.0º
RIGHT
- 0.25º ± 1.0º
-1.25º
+0.75º
CROSS
Max 2.0º
—
—
LEFT
151
CAMBER NOTES:
1
The camber angle is not adjustable. Do not bend axle or otherwise try to adjust camber. If found out of specification, notify
Hendrickson Tech Services for further information.
DESIGN SPECIFICATION
CASTER1,2
LEFT
RIGHT
RANGE
8K/10K
13.2K/14.6K
MINIMUM MAXIMUM MINIMUM
MAXIMUM
8K/10K
13.2K/14.6K
4.5º ± 1º
4.5° ± 1.5°
+3.5º
+5.5º
+3.0º
+6.0º
4.5º ± 1º
4.5° ± 1.5°
+3.5º
+5.5º
+3.0º
+6.0º
—
—
—
—
CROSS
Max 1.0º
3
CASTER NOTES:
1
Caster is determined with the vehicle at specified ride height for air suspension or at rated load for mechanical suspension
systems. It is critical that the vehicle front and rear ride height is within specifications prior to performing a caster
measurement or adjustment. See Hendrickson ride height specifications and procedure.
2
In most cases actual vehicle caster is defined with the frame rails at zero slope. Refer to the vehicle manufacturer’s
specifications for correct frame rail slope. (Both the alignment surface and the vehicle’s frame rails should be level during
execution of alignment procedures). For vehicles with a positive frame rake (higher in rear) add the frame slope (in
degrees) to the caster reading to determine true vehicle caster.
3
The Cross caster angle is not adjustable – Do not bend axle or otherwise try to adjust cross caster. If found out of
specifications notify Hendrickson Tech Services for further information. Changes to caster can be attained by using caster
shims as provided by the vehicle manufacturer or chassis and body manufacturer. Caster shims must match, side to side,
to reduce uneven loading to the suspension components. The use of two different angle caster shims will not correct
cross caster.
4
Example of caster adjustment: 2.5º RH/3º LH, would require one, 1.0 shim on each side to increase caster and achieve
3.50° RH/4.00° LH, which is in specification. Do not attempt to use uneven shims.
Hendrickson recommends following TMC2 practices:
DESIGN SPECIFICATION¹
TOTAL TOE
2
/ " ± / " (0.06" ± 0.03")
1 16
1 32
RANGE
MINIMUM
/ " (0.03")
1 32
MAXIMUM
/ " (0.09")
3 32
1
Toe-in is to be set and adjusted in the normal vehicle unladed configuration. Actual vehicle curb weight on the ground. Toe
should be checked at the tires front and rear tread center, at a distance above ground equal to the tire's rolling radius.
2
In most instances total toe is set by the vehicle manufacturer or body builder. Consult the vehicle manufacturer for
specifications.
17730–248
TOE-IN NOTES:
A-109
1
APPENDIX
L
SERVICE MANUAL
Technical Procedure Quiz
Technical Procedure Publication Quiz
1)
What three items have the greatest influence on tire wear?
a) Toe
b) Air Pressure
152
c) Camber
d) Thrust Angle
2)
Caster may be increased or decreased using shims or wedges.
True or False
3)
Cross caster may be changed using shims or wedges.
True or False
4)
You may bend a STEERTEK axle to correct for improper camber settings.
5)
In an unladen vehicle the correct toe setting for the STEERTEK axle is?
True or False
a) 0 to negative 1/8"
b) 0 to negative 1/16"
c) 0 to positive 1/32"
d) 1/16" ± 1/32"
6)
When reducing wheel cut on the STEERTEK axle it is necessary to check the steering gear
box poppets.
True or False
7)
The torque requirement for the front and rear spring hanger eye bolts
are the same.
True or False
8)
When servicing the clamp group a technician should always replace the following items.
a) Hex bolts/U-bolts (Grade 8) and nylon locknuts (Grade C)
b) Bottom axle wrap liner
c) Upper axle wrap liner, if removed
d) All of the above
9)
What is the clamp group final torque?
a)
500-550 foot pounds (678-746 Nm)
b)
290-310 foot pounds (393-420 Nm)
c)
285-305 foot pounds (386-414 Nm)
d)
240-275 foot pounds (325-373 Nm)
10) What is the
17730–248
a)
1,3,2,4
b)
1,4,2,3
c)
1,2,3,4
d)
The torque sequence does not matter.
11) For a vehicle equipped with a STEERTEK axle it is an acceptable practice to tow using a
tow chain wrapped around the axle.
True or False
12) The front leaf spring eye bushing is non serviceable
True or False
A-110
L
torque sequence for the clamp group? See Figure below.
1
APPENDIX
Front axle & suspension
Technical Procedure Quiz
13) To remove the STEERTEK knuckle you must.
a) Drive the kingpin out of the axle bore
b) Remove the locking pins before driving the kingpin out
c) Remove the two 5/8" socket head cap screws and separate the knuckle assembly
d) None of the above
14) What is the maximum allowable specification for lateral movement of the
steering knuckle?
153
a) 0.001"
b) 0.075"
c) 0.030"
d) 0.015"
15) When the AIRTEK ride height is checked, it is not necessary to cycle the leveling valve
before check the ride height.
True or False
16) Worn kingpins are easily removed and replaced.
True or False
17) The lower shock eye bolt mounting torque per the vehicle manufacturer is:
a)
125-135 foot pounds (169-183 Nm)
b)
225-255 foot pounds (305-346 Nm)
c) not critical
d) none of the above
18) Although the AIRTEK/SOFTEK is low maintenance, it is recommended to do a visual inspection on the axle and suspension every ___________ miles.
a) 100,000 or 1 year
b) 25,000 or 6 months
c) Never
19) When replacing the rear spring ¾" length hanger bolts, the new bolts should be installed:
a) From the outboard side to inboard side for AIRTEK 10K and SOFTEK 8K/10K
b) It does not matter what direction the bolts are facing
c) From the inboard side to outboard side for AIRTEK 14.6K and SOFTEK
13.2K/14.6K
d) Both a and c
20) The STEERTEK axle combined with the clamp group and stiff front spring limb help to make
the AIRTEK torsionally rigid and reduce body roll.
True or False
21) How many grease points are there on the STEERTEK axle?
a) 2
b) 6
c) 8
17730–248
d) None
22) It is acceptable to replace a failed shock absorber with any brand that will fit.
True or False
23) A shock that is misting is classified as a leaking shock and should be replaced immediately.
True or False
24) Wheel bearing adjustment has no impact on tire wear.
True or False
A-111
1
APPENDIX
L
SERVICE MANUAL
Technical Procedure Quiz
25) Prior to performing a total vehicle alignment the following components must be inspected.
a) Front and rear spring mounts
b) Steer axle tires
c) Ride height
d) All of the above
26) When the clamp group is disassembled the use of a cutting torch is acceptable to help
remove seized bolts and nuts.
154
True or False
27) Prior to steering knuckle re-assembly it is critical that residual Loctite be removed and reapplied from the upper kingpin connection.
True or False
28) AIRTEK is available exclusively with the STEERTEK axle.
True or False
29) To heat test a shock absorber you should drive a vehicle at moderate speeds for fifteen
minutes.
True or False
30) If the kingpin bushing is worn, then both bushings on that knuckle need to be replaced.
True or False
31) The unique packaging of the steering knuckle will allow up to ______ degrees of wheel cut
on the STEERTEK axle.
a) Maximum of 50°
b) 32°
c) 87°
d) None of the above
32) A pre-alignment inspection reveals a tie rod end is worn out of specification. What is the
correct action needed to complete the alignment.
a) Fill the tie rod with grease to absorb excessive play
b) Replace the tie rod and reset toe before alignment
c) Perform alignment and then replace tie rod end and reset toe
d) Align vehicle and do not repair tie rod end
33) The seal on the thrust bearings are installed facing down.
a) True
b) False
c) Doesn’t matter
34) When servicing tie rod ends it is not necessary to have the part number located on the tie
rod tube to order tie rod service kits.
True or False
CERTIFICATE
17730–248
Hendrickson
ATTN: Truck Marketing Test Quiz Assessment
800 S. Frontage Road
Woodridge, Illinois 60517
A-112
L
Hendrickson will provide a personalized AIRTEK/SOFTEK Technical Procedure Quiz
Achievement Certificate to candidates scoring 80% or higher on the test. Simply
complete the test and fill in the enclosed answer sheet or on a separate sheet with the
return address, name, phone number, and company name as it will appear on the
award to:
1
APPENDIX