Maxon GPT TUK-A-WAY® Maintenance Manual

Maxon GPT TUK-A-WAY® Maintenance Manual
M-17-08
REV. D
MARCH 2020
© MAXON Lift Corp. 2020
11921 Slauson Ave.
Santa Fe Springs, CA. 90670
LIFT CORP.
CUSTOMER SERVICE:
TELEPHONE (562) 464-0099 TOLL FREE (800) 227-4116
FAX: (888) 771-7713
NOTE: For latest version of all Manuals (and replacements), download the
Manuals from Maxon’s website at www.maxonlift.com.
WARRANTY/ RMA POLICY & PROCEDURE
LIFTGATE WARRANTY
Type of Warranty:
Full Parts and Labor
Term of Warranty:
Standard Liftgates - 2 years from ship date or 6,000 cycles
Premium Liftgates - 2 years from ship date or 10,000 cycles
This warranty shall not apply unless the product is installed, operated and maintained in accordance with MAXON Lift’s specifications as set forth in
MAXON Lift’s Installation, Operation and Maintenance manuals. This warranty does not cover normal wear, maintenance or adjustments, damage or
malfunction caused by improper handling, installation, abuse, misuse, negligence, or carelessness of operation. In addition, this warranty does not
cover equipment that has had unauthorized modifications or alterations made to the product.
MAXON agrees to replace any components which are found to be defective during the first 2 years of service, and will reimburse for labor based on
MAXON’s Liftgate Warranty Flat Rate Schedule. (Copy of the Flat Rate is available at www.maxonlift.com.)
All warranty repairs must be performed by an authorized MAXON warranty facility. For any repairs that may exceed $500, including parts and labor,
MAXON’s Technical Service Department must be notified and an “Authorization Number” obtained.
All claims for warranty must be received within 30 Days of the repair date, and include the following information:
1. Liftgate Model Number and Serial Number
2. The End User must be referenced on the claim
3. Detailed Description of Problem
4. Corrective Action Taken, and Date of Repair
5. Parts used for Repair, Including MAXON Part Number(s)
6. MAXON R.M.A. # and/or Authorization # if applicable (see below)
7. Person contacted at MAXON if applicable
8. Claim must show detailed information i.e. Labor rate and hours of work performed
Warranty claims can also be placed online at www.maxonlift.com. Online claims will be given priority processing.
All claims for warranty will be denied if paperwork has not been received or claim submitted via Maxon website for processing by MAXON’s Warranty
Department within 30 days of repair date.
All components may be subject to return for inspection, prior to the claim being processed. MAXON products may not be returned without prior written
approval from MAXON’s Technical Service Department. Returns must be accompanied by a copy of the original invoice or reference with original
invoice number and are subject to a credit deduction to cover handling charges and any necessary reconditioning costs. Unauthorized returns will be
refused and will become the responsibility of the returnee.
Any goods being returned to MAXON Lift must be pre-approved for return, and have the R.M.A. number written on the outside of the package in plain
view, and returned freight prepaid. All returns are subject to a 15% handling charge if not accompanied by a detailed packing list. Returned parts
are subject to no credit and returned back to the customer. Defective parts requested for return must be returned within 30 days of the claim date for
consideration to:
MAXON Lift Corp.
10321 Greenleaf Ave., Santa Fe Springs, CA 90670
Attn: RMA#__
MAXON’s warranty policy does not include the reimbursement for travel time, towing, vehicle rental, service calls, oil, batteries or loss of income due to
downtime. Fabrication or use of non Maxon parts, which are available from MAXON, are also not covered.
MAXON’s Flat Rate Labor Schedule takes into consideration the time required for diagnosis of a problem.
All Liftgates returned are subject to inspection and a 15% restocking fee. Any returned Liftgates or components that have been installed or not returned
in new condition will be subject to an additional reworking charge, which will be based upon the labor and material cost required to return the Liftgate or
component to new condition.
PURCHASE PART WARRANTY
Term of Warranty: 1 Year from Date of Purchase.
Type of Warranty: Part replacement only. MAXON will guarantee all returned genuine MAXON replacement parts upon receipt and inspection of parts
and original invoice.
All warranty replacements parts will be sent out via ground freight. If a rush shipment is requested, all freight charges will be billed to the requesting
party.
TABLE OF CONTENTS
SUMMARY OF CHANGES: M-17-08 REVISION D .............................................................. 6
WARNINGS ........................................................................................................................... 8
SAFETY INSTRUCTIONS .................................................................................................... 9
LIFTGATE TERMINOLOGY ................................................................................................ 10
PERIODIC MAINTENANCE................................................................................................ 11
PERIODIC MAINTENANCE CHECKS .................................................................................11
PERIODIC MAINTENANCE CHECKLIST ........................................................................... 12
CHECKING HYDRAULIC FLUID ........................................................................................ 14
CHANGING HYDRAULIC FLUID ........................................................................................ 16
REPLACING PLATFORM TORSION SPRING ................................................................... 18
PLATFORM ADJUSTMENT ................................................................................................ 19
DECALS (GPT) ................................................................................................................... 21
DECALS & PLATES (GPT) ................................................................................................ 23
DECALS (GPTWR) ............................................................................................................. 24
DECALS & PLATES (GPTWR) .......................................................................................... 26
SYSTEM DIAGRAMS ......................................................................................................... 27
PUMP MOTOR & SOLENOID SWITCH OPERATION - SINGLE PUMP ............................ 27
PUMP MOTOR & SOLENOID SWITCH OPERATION - DUAL PUMPS ............................. 28
HYDRAULIC SCHEMATIC (POWER DOWN) .................................................................... 30
ELECTRICAL SCHEMATIC (POWER DOWN) ................................................................... 31
HYDRAULIC SCHEMATIC (POWER DOWN) - DUAL PUMPS .......................................... 32
ELECTRICAL SCHEMATIC (POWER DOWN) - DUAL PUMPS ......................................... 33
GPT/GPTWR ELECTRICAL VALUES & TORQUE SPECIFICATIONS .............................. 34
TROUBLESHOOTING ........................................................................................................ 36
MOTOR WILL NOT RUN.................................................................................................... 36
PLATFORM WILL NOT RAISE, BUT MOTOR RUNS ......................................................... 37
PLATFORM RAISES BUT LEAKS DOWN .......................................................................... 38
PLATFORM RAISES PARTIALLY AND STOPS .................................................................. 40
LIFTGATE WILL NOT LIFT RATED CAPACITY .................................................................. 41
PLATFORM RAISES SLOWLY ........................................................................................... 42
PLATFORM WILL NOT LOWER, LOWERS TOO SLOWLY OR TOO QUICKLY ................ 44
PLATFORM BEGINS TO LOWER ON LH SIDE, BUT WILL NOT LOWER ON RH SIDE .. 46
PLATFORM WILL NOT TILT DOWN TO THE GROUND .................................................... 49
SUMMARY OF CHANGES: M-17-08 REVISION D
PAGE
COVER
8
DESCRIPTION OF CHANGE
Updated REV and date of release.
Added California Proposition 65 warning.
7
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THIS PAGE INTENTIONALLY LEFT BLANK
Comply with the following WARNINGS and SAFETY INSTRUCTIONS while installing
Liftgates. See Operation Manual for operating safety requirements.
!
WARNING
Installing and maintaining a liftgate can expose you to chemicals, including lead, which are known
to the State of California to cause cancer and birth defects or other reproductive harm. To minimize exposure, install and maintain liftgate in a well-ventilated area and wear proper Personal
protective equipment (PPE). For more information go to www.P65Warnings.ca.gov.
WARNINGS
!
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WARNING
• Do not stand, or allow obstructions, under the platform when lowering the Liftgate. Be sure your
feet are clear of the Liftgate.
• Keep fingers, hands, arms, legs, and feet clear of moving Liftgate parts (and platform
edges) when operating the Liftgate.
• Correctly stow platform when not in use. Extended platforms could create a hazard for
people and vehicles passing by.
• Make sure vehicle battery power is disconnected while installing Liftgate. Connect vehicle
battery power to the Liftgate only when installation is complete or as required in the installation
instructions.
• If it is necessary to stand on the platform while operating the Liftgate, keep your feet and any
objects clear of the inboard edge of the platform. Your feet or objects on the platform can become
trapped between the platform and the Liftgate extension plate.
• Never perform unauthorized modifications on the Liftgate. Modifications may result in early failure
of the Liftgate and may create hazards for Liftgate operators and maintainers.
• Recommended practices for welding on steel parts are contained in the current AWS (American
Welding Society) D1.1 Structural Welding Code - Steel. Damage to Liftgate and/or vehicle, and
personal injury can result from welds that are done incorrectly.
• Recommended practices for welding galvanized steel are contained in the current AWS (American Welding Society) D19.0 Welding Zinc-Coated Steel. Damage to Liftgate and/or vehicle, and
personal injury can result from welds that are done incorrectly.
8
SAFETY INSTRUCTIONS
SAFETY INSTRUCTIONS
• Before operating the Liftgate, read and understand the operating instructions in Operation
Manual.
• Comply with all WARNING and instruction decals attached to the Liftgate.
• Keep decals clean and legible. If decals are illegible or missing, replace them. Free replacement
decals are available from Maxon Customer Service.
• Consider the safety and location of bystanders and location of nearby objects when operating the
Liftgate. Stand to one side of the platform while operating the Liftgate.
• Do not allow untrained persons to operate the Liftgate.
• Wear appropriate safety equipment such as protective eyeglasses, faceshield and clothing while
performing maintenance on the Liftgate and handling the battery. Debris from drilling and contact
with battery acid may injure unprotected eyes and skin.
• Be careful working by an automotive type battery. Make sure the work area is well ventilated and
there are no flames or sparks near the battery. Never lay objects on the battery that can short the
terminals together. If battery acid gets in your eyes, immediately seek first aid. If acid gets on your
skin, immediately wash it off with soap and water.
• If an emergency situation arises (vehicle or Liftgate) while operating the Liftgate, release the control switch to stop the Liftgate.
• A correctly installed Liftgate operates smoothly and reasonably quiet. The only noticeable noise
during operation comes from the power unit while the platform is raised. Listen for scraping, grating and binding noises and correct the problem before continuing to operate Liftgate.
• Use only Maxon Authorized Parts for replacement parts. Provide Liftgate model and serial number information with your parts order. Order replacement parts from:
MAXON LIFT CORP. Customer Service
11921 Slauson Ave., Santa Fe Springs, CA 90670
Online: www.maxonlift.com
Express Parts Ordering: Phone (800) 227-4116 ext. 4345
Email: Ask your Customer Service representative
9
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
• Read and understand the instructions in this Maintenance Manual before performing maintenance on the Liftgate.
LIFTGATE TERMINOLOGY
LICENSE PLATE
BRACKET
EXTENSION PLATE
(GPT MODEL SHOWN)
MAIN
FRAME
CONTROL
SWITCH
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PLATFORM
OPENER
PUMP ASSEMBLY
(COVER IS
SHOWN)
BUMPER
DUAL STEP
PARALLEL
ARM
PLATFORM
LIFT
CYLINDER
TORSION
SPRING
PUMP MOUNTING
PLATE BRACKET
LIFT
ARM
WEDGE FLIPOVER
10
PERIODIC MAINTENANCE
!
WARNING
Never operate the Liftgate if parts are loose or missing.
NOTE: Make sure vehicle is parked on level ground while performing the
maintenance checks.
Quarterly or 1250 Cycles (whichever occurs first)
Check the hydraulic fluid level in the pump reservoir. Refer to the CHECKING HYDRAULIC
FLUID procedure in the PERIODIC MAINTENANCE section.
If hydraulic fluid appears contaminated, refer to the CHANGING HYDRAULIC FLUID
procedure in the PERIODIC MAINTENANCE section.
Keep track of the grade of hydraulic fluid in the pump reservoir and never mix two different
grades of fluid.
Check all hoses and fittings for chafing and fluid leaks. Tighten loose fittings or replace
parts as required.
Check electrical wiring for chafing and make sure wiring connections are tight and free of
corrosion. Use dielectric grease to protect electrical connections.
Check that all WARNING and instruction decals are in place. Also, make sure decals are
legible, clean and undamaged.
Check that all bolts, nuts, and roll pins are in place. Make sure roll pins protrude evenly
from both sides of hinge pin collar. Replace fasteners and roll pins if necessary.
Pump EP chassis grease in each lube fitting on the cylinders and arms until grease
starts oozing from ends of the bearings. The lubrication diagram on the PERIODIC
MAINTENANCE CHECKLIST SHEET shows where to find the lube fittings. Wipe off
excess grease with a clean lint-free cloth.
CAUTION
Damaged cylinder seals and contaminated hydraulic fluid can result from painting the polished portion of the cylinder rod. To prevent damage, protect the
exposed polished portion of the cylinder rod while painting.
Check for rust and oily surfaces on Liftgate. If there is rust or oil on Liftgate, clean it off.
Touch up the paint where bare metal is showing. MAXON recommends using the aluminum
primer touchup paint kit, P/N 908134-01.
Semi-annually or 2500 Cycles (whichever occurs first)
Visually check the platform hinge pins for excessive wear and broken welds. See PARTS
BREAKDOWN section for replacement parts. Also, do the Quarterly or 1250 Cycles
maintenance checks.
11
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PERIODIC MAINTENANCE CHECKS
PERIODIC MAINTENANCE CHECKLIST
NOTE: Make sure vehicle is parked on level ground while performing maintenance
checks.
Quarterly or 1250 Cycles (whichever occurs first)
Check the level and condition of the hydraulic fluid.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
Visually check all hoses and fittings for chafing and fluid leaks. Tighten loose fittings or
replace parts as required.
Check electrical wiring for chafing and make sure wiring connections are tight and free
of corrosion. Use dielectric grease to protect electrical connections.
Check that all WARNING and instruction decals are in place. Also, make sure decals
are legible, clean, and undamaged.
Check that all bolts, nuts, and roll pins are in place. Make sure roll pins protrude evenly
from both sides of hinge pin collar. Replace fasteners and roll pins if necessary.
Check for rust and oily surfaces on Liftgate. If there is rust or oil on Liftgate or if the
Liftgate is dirty, clean it off. Touch up the paint where bare metal is showing. Refer to
the paint system CAUTION and recommended touchup kit on the preceding page.
Pump EP chassis grease in each lube fitting on the cylinders and arms until grease
starts oozing from ends of the bearings. Refer to lubrication diagram on the next
page. Wipe off excess grease with a clean lint-free cloth.
Semi-annually or 2500 Cycles (whichever occurs first)
Visually check the platform hinge pins for excessive wear and broken welds.
Do the Quarterly or 1250 Cycles Checks on this checklist.
12
NOTE: Lube fittings are shown for the RH cylinder, lift arm, and parallel
arm. There are also lube fittings at the same places on the LH
cylinder, lift arm, and parallel arm.
Refer to lubrication diagram (FIG. 13-1) to find the
lube fittings on cylinders and arms. Pump EP chassis
grease in each lube fitting on the cylinders and arms
until grease starts oozing from ends of the bearings.
Then, wipe off excess grease with a clean lint-free
cloth.
LH CYLINDER,
LIFT ARM &
PARALLEL ARM
RH CYLINDER,
LIFT ARM &
PARALLEL ARM
GPT LUBRICATION DIAGRAM
FIG. 13-1
13
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PERIODIC MAINTENANCE CHECKLIST
PERIODIC MAINTENANCE
CHECKING HYDRAULIC FLUID
CAUTION
Keep dirt, water and other contaminants from entering the hydraulic system.
Before opening the hydraulic fluid reservoir filler cap, drain plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the
openings from accidental contamination.
NOTE: Use correct grade of hydraulic fluid for your location.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
+50 to +120 Degrees F - Grade ISO 32
Below + 70 Degrees F - Grade ISO 15 or MIL-H-5606
See TABLES 15-1 & 15-2 for recommended brands.
1. Unfasten and remove pump cover
(FIG. 14-1).
POWER UNIT
(REF)
LONGER SIDE OF
HOLDER FLATS BUTT
AGAINST COVER
2. Check the hydraulic fluid level in
reservoir with Liftgate stowed, or
platform at vehicle bed height.
NOTE: If the hydraulic fluid in the
reservoir is contaminated, do
the CHANGING HYDRAULIC
FLUID procedure in this section.
PUMP
COVER
NOTE: Information for checking OIL
LEVEL is shown on a decal on
the pump reservoir.
FLAT WASHER
(2 PLACES)
KNOB
(2 PLACES)
UNFASTENING / FASTENING
PUMP COVER
FIG. 14-1
3. Check if hydraulic fluid level is in the
range shown on decal (FIG. 14-2). If
necessary, remove filler cap (FIG. 14-2)
and add hydraulic fluid until level rises
within the range on decal (FIG. 14-2).
Then, reinstall filler cap (FIG. 14-2).
FILLER
CAP
CAUTION
Pump cover must be correctly secured to prevent it from becoming
a hazard. To secure pump cover,
the long side of the holder flats
must butt against pump cover as
shown in the illustration.
4. Install and fasten the pump cover as
shown in FIG. 14-1. Hand-tighten the
cover knobs.
POWER UNIT FLUID LEVEL
FIG. 14-2
14
RECOMMENDED
BRANDS
PART NUMBER
CHEVRON
HIPERSYN 32
KENDALL
GOLDEN MV
SHELL
TELLUS S2 VX 32
EXXONMOBIL
UNIVIS N-32, DTE-24
TABLE 15-1
ISO 15 OR MIL-H-5606 HYDRAULIC FLUID
RECOMMENDED
BRANDS
PART NUMBER
CHEVRON
FLUID A, AW-MV-15
KENDALL
GLACIAL BLU
SHELL
TELLUS S2 VX 15
EXXONMOBIL
UNIVIS HVI-13
ROSEMEAD
THS FLUID 17111
TABLE 15-2
15
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ISO 32 HYDRAULIC FLUID
PERIODIC MAINTENANCE
CHANGING HYDRAULIC FLUID
CAUTION
Keep dirt, water and other contaminants from entering the hydraulic system.
Before opening the hydraulic fluid reservoir filler cap, drain plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the
openings from accidental contamination.
NOTE: Use correct grade of hydraulic fluid for your location.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
+50 to +120 Degrees F - Grade ISO 32
Below + 70 Degrees F - Grade ISO 15 or MIL-H-5606
See TABLES 15-1 & 15-2 for recommended brands.
1. Unfasten and remove pump
LONG SIDE OF
HOLDER FLATS
BUTT AGAINST
COVER
cover (FIG. 16-1). Place empty
5 gallon bucket under drain plug
(FIG. 16-2).
POWER UNIT
(REF)
PUMP
COVER
FLAT
WASHER
(2 PLACES)
KNOB
(2 PLACES)
REMOVING PUMP COVER
FIG. 16-1
2. Open and raise platform to vehicle bed
height. Pull out (no threads) drain plug
(FIG. 16-2). Drain hydraulic fluid.
DRAIN PLUG
POWER UNIT
FIG. 16-2
16
4. Pull out (no threads) filler cap (FIG.
17-2). Add hydraulic fluid until level rises within the range on decal (FIG. 17-2).
Then, reinstall filler cap (FIG. 17-2).
WHITE
WIRE
DISCONNECTING WHITE WIRE
FIG. 17-1
5. Stow the Liftgate and do the CHECKING HYDRAULIC FLUID procedure in
this section of the manual.
CAUTION
FILLER
CAP
Pump cover must be correctly secured to prevent it from becoming
a hazard. To secure pump cover,
the long side of the holder flats
must butt against pump cover as
shown in the illustration.
6. Install and fasten the pump cover as
shown in FIG. 17-3. Hand-tighten the
cover knobs.
POWER UNIT FLUID LEVEL
FIG. 17-2
LONG SIDE OF
HOLDER FLATS
BUTT AGAINST
COVER
POWER UNIT
(REF)
PUMP
COVER
FLAT
WASHER
(2 PLACES)
KNOB
(2 PLACES)
INSTALLING PUMP COVER
FIG. 17-3
17
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3. Disconnect the white wire (FIG. 17-1) from
the positive (+) power post on the solenoid
switch. Lower the platform while draining the
remaining hydraulic fluid from system. Reinstall drain plug. Reconnect the
white wire to the positive (+) power post on
the solenoid switch.
PERIODIC MAINTENANCE
REPLACING PLATFORM TORSION SPRING
NOTE: The following procedure shows how to replace torsion spring on RH side of
platform. Use this procedure for replacing torsion spring on the LH side.
1. Manually fold flipover onto platform.
PLATFORM
(REFERENCE)
2. Raise platform to a convenient work height
to gain access and release tension on the
torsion spring.
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!
HINGE PIN
CAUTION
LOCK
NUT
BOLT
To prevent injury and equipment
damage, make sure there is no
tension on torsion spring before
removing hinge pin.
3. Unbolt hinge pin from hinge bracket
(FIG. 18-1). Remove bolt and lock nut.
Drive the hinge pin inboard toward the
shackle with a hammer and pin punch,
just enough to free the torsion spring
(FIG. 18-1). Remove spring from shackle.
FIG. 18-1
4. Install the torsion spring as shown in
FIG. 18-2. Make sure the long leg
of the spring is inserted in the bracket
located on shackle (FIG. 18-2). Make
sure the short end of the spring is visible and resting against the edge of the
hinge bracket (FIG. 18-2).
5. Drive the hinge pin into correct position (FIG. 18-2) through the hinge
bracket with a hammer and pin
punch. Line up the bolt hole in the
hinge pin with the hole in the hinge
bracket. Bolt the hinge pin to hinge
bracket with bolt and lock nut (FIG.
18-2).
TORSION
SPRING
HINGE
BRACKET
HINGE PIN
SHACKLE
HINGE
BRACKET
PLATFORM
(REFERENCE)
BRACKET
BOLT &
LOCK NUT
SHORT
LEG
6. Operate the Liftgate to make
sure it operates correctly.
LONG
LEG
SHACKLE
FIG. 18-2
18
NOTE: Before doing the following procedure, make sure vehicle is parked
on level ground.
1. With the platform and flipover unfolded,
raise platform to bed level (FIG. 19-1).
Measure how much the outboard edge
of platform rises above bed level (FIG.
19-1). The outboard edge must be level
or a maximum of 1” above bed level (FIG.
19-1). If indication is correct, Liftgate
is installed correctly and no adjustment
is needed. If the outboard edge is below
bed level, do instructions 2, 3, and 6. If
outboard edge is higher than 1”, do instructions 4 through 6.
EXTENSION
PLATE (REF)
OUTBOARD EDGE
1” MAX (UP TO 53” BED HT.)
0” LEVEL (OVER 53” BED HT.)
VEHICLE
FLOOR (REF)
LEVEL LINE
PLATFORM EDGE AT OR
ABOVE BED LEVEL
FIG. 19-1
EXTENSION
PLATE (REF)
2. Compare measurement “A” (FIG.
19-2) with the distances and shims in
TABLE 19-1. For example: If measurement “A” (FIG. 19-2) is 1” below
level and you want to raise outboard
edge of platform 1” above level, use
1/8” shim to raise 2” (TABLE 19-1).
VEHICLE
FLOOR (REF)
“A”
LEVEL LINE
PLATFORM EDGE BELOW BED LEVEL
FIG. 19-2
RAISE PLATFORM
REQUIRED SHIM
WELD SIZE
THICKNESS
“W”
1”
1/16”
1/16”
2”
1/8”
1/8”
3”
3/16”
3/16”
4”
1/4”
1/4”
EDGE (OUTBOARD)
THIS DISTANCE (“A”)
SHACKLE
(REF)
TABLE 19-1
3. Weld shims (parts bag item) on both
platform stops (FIG. 19-3) to raise
outboard edge of platform to correct
position.
NEW SHIM
(TABLE 19-1)
“W”
“W”
(TABLE 19-1)
WELDING SHIMS (CURBSIDE SHOWN)
FIG. 19-3
19
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PLATFORM ADJUSTMENT
PERIODIC MAINTENANCE
PLATFORM ADJUSTMENT - Continued
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4. Compare measurement “B” (FIG.
20-1) with the distances and grinding
depths in TABLE 20-1. For example:
If measurement “B” (FIG. 20-1) is 3”
above bed level and you want to lower
the outboard edge of platform to 1”
above bed level, grind 1/8” from each
platform stop (TABLE 20-1).
LOWER PLATFORM
EDGE (OUTBOARD)
THIS DISTANCE (“B”)
GRIND METAL
FROM PLATFORM
STOP
1”
1/16”
2”
1/8”
3”
3/16”
4”
1/4”
EXTENSION
PLATE (REF)
“B”
VEHICLE
FLOOR (REF)
LEVEL LINE
PLATFORM EDGE ABOVE BED LEVEL
FIG. 20-1
TABLE 20-1
SHACKLE
(REF)
5. Grind metal from platform stops (FIG.
20-2) to lower outboard edge of platform to correct position.
GRIND THIS FACE
(SEE TABLE 20-1)
GRINDING PLATFORM STOPS
(CURBSIDE SHOWN)
FIG. 20-2
6. Lower the platform, then raise it to bed
level. The outboard edge of platform should
be level or up to 1” maximum above bed
level (FIG. 20-3).
EXTENSION
PLATE (REF)
OUTBOARD EDGE
1” MAX (UP TO 53” BED HT.)
0” LEVEL (OVER 53” BED HT.)
VEHICLE
FLOOR (REF)
LEVEL LINE
PLATFORM EDGE ABOVE BED LEVEL
FIG. 20-3
20
DECALS (GPT)
NOTE: Preferred decal layout is shown. Decals on the Liftgate are attached at the
factory. If vehicle does not permit this layout, decals in the manual and decal
kit must be applied so that they are easily visible when approaching vehicle
to operate Liftgate. Use good common sense when locating these decals on
vehicle.
UP DECAL
(DECAL SHEET)
DECAL “D”
DECAL “E”
DECAL “C”
DOWN DECAL
(DECAL SHEET)
DECAL “B”
CAPACITY DECAL
(SEE TABLE 22-1)
DECAL “A”
FIG. 21-1
21
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NOTE: Ensure there is no residue, dirt or corrosion where decals are attached. If
necessary, clean surface before attaching decals.
DECALS (GPT) - Continued
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DECAL SHEET
P/N 297205-01
FIG. 22-1
MODEL
DECAL P/N
CAPACITY
DECAL
GPT-25
220382
2500 POUNDS
GPT-3
220388
3000 POUNDS
GPT-4
296274-01
4000 POUNDS
GPT-5
296274-02
5000 POUNDS
CAPACITY DECAL
TABLE 22-1
22
DECALS & PLATES (GPT)
MAXON NAME PLATE
P/N 280004-01
MAXON 24/7
SUPPORT DECAL
P/N 298634-01
PARTS QR CODE DECAL
P/N 299348-05
SERIAL PLATE
(REF)
PLATFORM WARNING DECAL
P/N 281189-02
(2 PLACES)
PLATFORM LOADING DECAL
P/N 281326-01
(2 PLACES)
FIG. 23-1
23
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
NOTE: Preferred decal layout is shown. Decals on
the Liftgate are attached at the factory.
DECALS (GPTWR)
NOTE: Ensure there is no residue, dirt or corrosion where decals are attached. If
necessary, clean surface before attaching decals.
NOTE: Preferred decal layout is shown. Decals on the Liftgate are attached at the
factory. If vehicle does not permit this layout, decals in the manual and decal
kit must be applied so that they are easily visible when approaching vehicle
to operate Liftgate. Use good common sense when locating these decals on
vehicle.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
UP DECAL
P/N 299038-01
DECAL “D”
DECAL “E”
DECAL “B”
DOWN DECAL
P/N 299038-01
DECAL “H”
DECAL “A”
CAPACITY DECAL
(SEE TABLE 25-1)
DECAL “C”
DECAL “G”
FIG. 24-1
24
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
DECAL SHEET
P/N 297207-01
FIG. 25-1
MODEL
CAPACITY
DECAL
DECAL P/N
GPTWR-25
220382
2500 POUNDS
GPTWR-3
220388
3000 POUNDS
GPTWR-4
296274-01
4000 POUNDS
GPTWR-5
296274-02
5000 POUNDS
CAPACITY DECAL
TABLE 25-1
25
DECALS & PLATES (GPTWR)
NOTE: Preferred decal layout is shown. Decals on
the Liftgate are attached at the factory.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
MAXON NAME PLATE
P/N 280004-01
MAXON 24/7
SUPPORT DECAL
P/N 298634-01
PARTS QR CODE
DECAL
P/N 299348-06
SERIAL PLATE
(REF)
PLATFORM WARNING DECAL
P/N 281189-02
(2 PLACES)
PLATFORM LOADING DECAL
P/N 281326-01
(2 PLACES)
FIG. 26-1
26
SYSTEM DIAGRAMS
POWER DOWN
MODULE
PORT A
MOTOR
“S2” VALVE
“S1” VALVE
SOLENOID
SWITCH
PORT B
POWER UNIT
FIG. 27-1
NOTE: Hydraulic lock valve is on the RH cylinder.
PUMP MOTOR & SOLENOID SWITCH OPERATION
LIFTGATE
FUNCTION
SOLENOID SWITCH OPERATION
( MEANS ENERGIZED)
PORT
MOTOR
RAISE
A
LOWER
B
VALVE
“S2”
VALVE
“S1”
-
REFER TO VALVES SHOWN ON
HYDRAULIC SCHEMATIC
TABLE 27-1
27
LOCK
VALVE
POWER
DOWN
MODULE
-
-
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
PUMP MOTOR & SOLENOID SWITCH OPERATION - SINGLE PUMP
PUMP MOTOR & SOLENOID SWITCH OPERATION - DUAL PUMPS
MOTOR
PUMP
MOUNTING
PLATE
SOLENOID
SWITCH
PUMP #2
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
PORT C2
PORT C1
“S1” VALVE
MOTOR
DUAL PUMP POWER UNIT - REAR VIEW
FIG. 28-2
SOLENOID
SWITCH
PUMP #1
DUAL PUMP POWER UNIT
FIG. 28-1
NOTE: Hydraulic lock valves are located on the RH & LH
cylinders.
PUMP MOTOR & SOLENOID SWITCH OPERATION
LIFTGATE
FUNCTION
SOLENOID SWITCH OPERATION
( MEANS ENERGIZED)
PORT
MOTOR
VALVE
“S1”
LOCK
VALVES
-
RAISE
C1
-
LOWER
C2
REFER TO VALVES SHOWN ON
HYDRAULIC SCHEMATIC
TABLE 28-1
28
ARC
SUPPRESSION
MODULE
29
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THIS PAGE INTENTIONALLY LEFT BLANK
SYSTEM DIAGRAMS - Continued
HYDRAULIC SCHEMATIC (POWER DOWN)
HYDRAULIC
CYLINDERS
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
HYDRAULIC
LOCK VALVE
PORT B - LOWER
(POWER DOWN)
PORT A - RAISE
VALVE S2
4 GPM FLOW
CONTROL
VALVE
RELIEF VALVE 2
(SET AT 1100 PSI)
VALVE S1
RELIEF VALVE 1
(SET AT 2750 PSI)
CHECK VALVE
MOTOR
(REF)
PUMP
FILTER
RESERVOIR
DRAIN HOLE
(PLUGGED)
FIG. 30-1
30
AUX. HAND
PUMP PORT
(PLUGGED)
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
ELECTRICAL SCHEMATIC (POWER DOWN)
NOTE: One cycle is counted when
the down switch is activated
for 5-7 continuous seconds.
FIG. 31-1
31
HYDRAULIC SCHEMATIC (POWER DOWN) - DUAL PUMPS
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
LH HYDRAULIC
CYLINDER
RH HYDRAULIC
CYLINDER
HYDRAULIC
LOCK VALVE
HYDRAULIC
LOCK VALVE
3 GPM FLOW
CONTROL
VALVE
PORT C2 - DOWN VENT
PORT C1 - RAISE
VENT
GAUGE PORT
(PLUGGED)
RELIEF VALVE 2
(SET AT 1800 PSI)
VALVE S1
CHECK VALVES
RELIEF VALVE 1
(SET AT 2750 PSI)
MOTOR
(REF)
MOTOR
(REF)
M
M
PUMP #2
PUMP #1
FILTER
FILTER
RESERVOIR
DRAIN HOLE
(PLUGGED)
FIG. 32-1
32
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ELECTRICAL SCHEMATIC (POWER DOWN) - DUAL PUMPS
BLACK
NOTE: One cycle is counted when
the down switch is activated
for 5-7 continuous seconds.
BLACK
FIG. 33-1
33
SYSTEM DIAGRAMS
GPT/GPTWR ELECTRICAL VALUES & TORQUE SPECIFICATIONS
Solenoid Switch
12V
24V
Coil resistance:
5.4Ω @70ºF. ±15%
20.1Ω @70ºF. ±15%
Ampere:
2.2A
1.2A
Coil resistance:
4.0Ω @ 70ºF. ±15%
26.7Ω @ 70ºF. ±15%
Ampere:
3A, 2.5A @10V
Coil terminal torque: 10-15 lb-in max.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
Contact terminal torque: 30-35 lb-in max.
Solenoid Valves (A, S1, & S2)
Coil terminal torque: 15-45 lb-in max.
Valve cartridge torque: 25-30 lb-ft max.
Coil nut torque: 15-45 lb-in
Solenoid Lock Valve
Coil resistance:
8.0Ω @ 70ºF. ±15%
30Ω @ 70ºF. ±15%
Ampere:
1.5A
0.8A
4V - 30V
4V - 30V
Coil nut torque: 3-4.5 lb-ft max.
Valve cartridge torque: 18.5-22 lb-ft max.
Digital Cycle Counter
Operation voltage
Ampere
<2mA
Ground Cable
Cap screw torque: 24 lb-ft max.
TABLE 34-1
34
35
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THIS PAGE INTENTIONALLY LEFT BLANK
TROUBLESHOOTING
MOTOR WILL NOT RUN
1. Connect voltmeter between solenoid switch terminal “B” and ground wires connection
on pump (FIG. 36-1). Verify that full battery voltage is at “B.” Recharge the battery if voltmeter indicates less than 12.4 volts DC.
2. Connect voltmeter between solenoid switch terminal “D” and ground wires connection
on pump (FIG. 36-1). Set control switch to “UP.” Verify that full battery voltage is at “D,”
if not, replace the power down module.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
3. Touch a jumper wire to terminals “B” & “D” (FIG. 36-1). If motor runs, check control
switch, the switch connections, and white wire. Check and correct wiring connections
or replace the control switch.
4. Touch heavy jumper cables to terminals “A” & “B” (FIG. 36-1).
a. If motor runs, replace the solenoid swich.
b. If motor does not run, repair or replace the pump motor.
GROUND (-) WIRE
CONNECTION
POWER DOWN
MODULE
(- VOLTMETER
LEAD)
SOLENOID
SWICH
TERMINAL “A”
LOAD
TERMINAL “D”
COIL DRIVE (+)
TERMINAL “C”
GROUND (-)
FIG. 36-1
36
TERMINAL “B”
BATTERY (+)
1. Do the CHECKING HYDRAULIC FLUID
procedure in this manual. If necessary,
add hydraulic fluid.
2. Check for the following. (Refer to ELECTRICAL SCHEMATIC.)
• Ground connections are clean and tight at battery and pump.
Clean and/or tighten if necessary.
• The (+) and (-) battery cable connections are clean and tight
at battery and pump. Clean and/or tighten if necessary.
• Voltage drops on battery/power cables (use voltmeter).
Clean and/or tighten connections or replace cables that
indicate voltage drops.
3. Check for structural damage and replace worn parts.
CAUTION
Keep dirt, water and other contaminants from
entering the hydraulic system. Before opening the hydraulic fluid reservoir filler cap, drain
plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the openings from accidental contamination during maintenance.
2750 PSI
RELIEF VALVE
LOCK NUT
NOTE: In most cases, you can avoid having to
manually bleed hydraulic system by
correctly positioning Liftgate platform
before disconnecting any lifting cylinder high pressure hydraulic lines.
4. Check pump oil filter in the reservoir
(FIG. 37-1). Clean or replace filter, if
necessary.
5. Check for dirty 2750 psi relief valve
(FIG. 37-1). Clean or replace relief
valve, if necessary.
RESERVOIR
(PUMP OIL FILTER INSIDE)
CHECKING 2750 PSI RELIEF VALVE
FIG. 37-1
37
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PLATFORM WILL NOT RAISE, BUT MOTOR RUNS
PLATFORM RAISES BUT LEAKS DOWN
GROUND (-)
WIRE
CONNECTION
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
1. Check if the “S2” (lowering) solenoid valve is constantly energized.
Connect voltmeter negative (-)
lead to ground (-) wires connection on pump and positive (+) lead
to (+) terminal on the “S2” (lowering) solenoid valve (FIG. 38-1). If
voltmeter indicates battery voltage, check for faulty wiring or
toggle switch.
“S2”
(LOWERING)
SOLENOID
VALVE
“S2”
(LOWERING)
SOLENOID
VALVE
(+) WHITE
WIRE
CONNECTION
MOTOR
FIG. 38-1
CAUTION
Keep dirt, water and other contaminants
from entering the hydraulic system. Before
opening the hydraulic fluid reservoir filler
cap, drain plug and hydraulic lines, clean up
contaminants that can get in the openings.
Also, protect the openings from accidental
contamination during maintenance.
VALVE
CARTRIDGE
NOTE: In most cases, you can avoid having
to manually bleed hydraulic system by
correctly positioning Liftgate platform
before disconnecting any lifting cylinder high pressure hydraulic lines.
2. Make sure platform is on the ground. Remove
lowering solenoid valve (FIG. 38-2). Push on
the plunger in the valve by inserting small
screwdriver in the open end (FIG. 38-3). If the
plunger does not move with a smooth, springloaded action (approximately 1/8”), replace the
valve cartridge. Reinstall lowering solenoid
valve. Torque valve cartridge to 30 lb-ft and
hex nut to 30 lb-in.
COIL
NUT
REMOVING SOLENOID VALVE
FIG. 38-2
VALVE CARTRIDGE
1/8”
CHECKING SOLENOID VALVE
FIG. 38-3
38
RAISE PORT
LOWER PORT
FIG. 39-1
39
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3. Check the hydraulic cylinder. With the platform at vehicle floor level, remove the hydraulic line from the LOWER port on the cylinder (FIG. 39-1). Hold the control switch
in the UP position for two seconds while you
watch for hydraulic fluid at the LOWER port.
A few drops of hydraulic fluid escaping the
port is normal. However, if fluid streams out,
piston seals are worn. Replace seals.
PLATFORM RAISES PARTIALLY AND STOPS
1. Lower the opened platform to the ground. Do the
CHECKING HYDRAULIC FLUID procedure in
this manual. If necessary, add hydraulic fluid.
2. Use voltmeter to verify the battery voltage is 10.5
volts or more under load from pump motor.
3. Check for structural damage and poor lubrication.
Replace worn parts.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
2750 PSI
RELIEF VALVE
CAUTION
Keep dirt, water and other contaminants from
entering the hydraulic system. Before opening the hydraulic fluid reservoir filler cap, drain
plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the openings from accidental contamination during maintenance.
LOCK NUT
NOTE: In most cases, you can avoid having to
manually bleed hydraulic system by correctly positioning Liftgate platform before
disconnecting any lifting cylinder high
pressure hydraulic lines.
4. Check for dirty 2750 psi relief valve
(FIG. 40-1). Clean or replace 2750 psi
relief valve, if necessary.
5. Check the hydraulic cylinder. With the platform at vehicle floor level, remove the hydraulic line from the LOWER port on the cylinder (FIG. 40-2). Hold the control switch
in the UP position for two seconds while you
watch for hydraulic fluid at the LOWER port.
A few drops of hydraulic fluid escaping the
port is normal. However, if fluid streams out,
piston seals are worn. Replace seals.
6. Check pump oil filter in the reservoir
(FIG. 40-1). Clean or replace filter, if
necessary.
RESERVOIR
(PUMP OIL FILTER INSIDE)
FIG. 40-1
RAISE PORT
LOWER PORT
FIG. 40-2
40
1. Use voltmeter to verify the battery voltage is 10.5
volts or more under load from pump motor.
2. Check for structural damage or lack of lubrication. Replace worn parts.
CAUTION
Keep dirt, water and other contaminants from entering the hydraulic system.
Before opening the hydraulic fluid reservoir filler cap, drain plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the
openings from accidental contamination during maintenance.
NOTE: In most cases, you can avoid having to manually bleed hydraulic system by
correctly positioning Liftgate platform before disconnecting any lifting cylinder
high pressure hydraulic lines.
2750 PSI
RELIEF VALVE
CAUTION
Before disconnecting UP line, ensure DOWN line &
elbow are connected to port B.
LOCK NUT
3. Check the 2750 psi relief valve as follows. With
platform on the ground, disconnect UP line from
Port “A” and remove elbow (FIG. 41-1). Install
0-3000 psi pressure gauge in Port “A” (FIG.
41-1). Loosen relief valve lock nut and hold the
control switch in the UP position. Adjust the relief
valve until the gauge reads 2750 psi (FIG. 41-1).
Remove gauge and reinstall elbow and up line.
Then, reinstall relief valve cover.
PRESSURE
GAUGE
UP LINE
PORT
“A”
4. Check if pump relief valve is dirty. Clean or
replace relief valve, if necessary.
5. Check the hydraulic cylinder. With the platform
at vehicle floor level, remove the hydraulic line
from the LOWER port on the cylinder (FIG. 41-2).
Hold the control switch in the UP position for two
seconds while you watch for hydraulic fluid at the
LOWER port. A few drops of hydraulic fluid escaping the port is normal. However, if fluid streams
out, piston seals are worn. Replace seals.
6. If pump cannot produce 2750 psi or lift
the load capacity with a minimum of
12.6 volts available, the pump is worn
and needs to be replaced.
FIG. 41-1
RAISE PORT
LOWER PORT
FIG. 41-2
41
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
LIFTGATE WILL NOT LIFT RATED CAPACITY
PLATFORM RAISES SLOWLY
1. Connect voltmeter between solenoid switch terminal “B” and ground (-) wires connection on pump
(FIG. 42-1). Verify that full battery voltage is at “B.”
Recharge the battery if voltmeter indicates less than
12.4 volts DC.
GROUND (-) WIRES
CONNECTION
CAUTION
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
Keep dirt, water and other contaminants from
entering the hydraulic system. Before opening the hydraulic fluid reservoir filler cap, drain
plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the openings from accidental contamination during maintenance.
NOTE: In most cases, you can avoid having to
manually bleed hydraulic system by
correctly positioning Liftgate platform before
disconnecting any lifting cylinder high pressure hydraulic lines.
2. Check the hydraulic cylinder. With the platform at vehicle floor level, remove the hydraulic line from the
LOWER port on the cylinder (FIG. 42-2). Hold the
control switch in the UP position for two seconds while
you watch for hydraulic fluid at the LOWER port. A few
drops of hydraulic fluid escaping the port is normal.
However, if fluid streams out, piston seals are worn.
Replace seals.
TERMINAL “B”
BATTERY (+)
FIG. 42-1
RAISE PORT
LOWER PORT
FIG. 42-2
CAUTION
To prevent damage to flow control valve, do not
disassemble the valve.
3. Check the flow control valve as follows. Remove lowering solenoid valve and flow control
valve (FIG. 42-3). Ensure the flow control valve
operates with a smooth spring-loaded action.
Check for debris inside the valve. Clean or
replace the flow control valve, if necessary. Reinstall flow control valve (if good) or a replacement. Then, reinstall the lowering solenoid
valve. Torque valve cartridge to 30 lb-ft and
hex nut to 30 lb-in.
42
FLOW CONTROL
VALVE
COIL
VALVE
CARTRIDGE
FIG. 42-3
NUT
5. Check for leaking hoses and fittings. Tighten or replace as required.
6. Check for structural damage and poor lubrication.
Replace worn parts.
7. Check pump oil filter in the reservoir (FIG. 43-1).
Clean or replace filter, if necessary.
CAUTION
Before disconnecting UP line, ensure
DOWN line & elbow are connected to port
B.
8. Check the 2750 psi relief valve as follows. With
platform on the ground, disconnect UP line from
Port “A” and remove elbow (FIG. 43-1). Install
0-3000 psi pressure gauge in Port “A” (FIG.
43-1). Loosen relief valve lock nut and hold the
control switch in the UP position. Adjust the relief
valve until the gauge reads 2750 psi (FIG. 43-1).
Remove gauge and reinstall elbow and up line.
Then, reinstall relief valve cover.
2750 PSI
RELIEF VALVE
LOCK NUT
PRESSURE
GAUGE
UP LINE
PORT
“A”
FIG. 43-1
43
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
4. Verify the pump motor is grounded to vehicle frame.
PLATFORM WILL NOT LOWER, LOWERS TOO SLOWLY OR TOO QUICKLY
GROUND (-) WIRE
CONNECTION
1. Connect voltmeter (+) lead to motor solenoid terminal “B” and the (-) lead to the
ground wires connection on pump (FIG.
44-1). Verify that full battery voltage is at
“B.” Recharge the battery if voltmeter indicates less than 12.6 volts DC.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
“S2”
(LOWERING)
SOLENOID
VALVE
2. Check for structural damage or poor
lubrication. Replace worn parts.
MOTOR
TERMINAL “D”
COIL DRIVE (+)
TERMINAL “B”
BATTERY (+)
FIG. 44-1
3. Check if the “D” terminal and “S2” (lowering) solenoid valve are getting battery voltage (FIG. 44-1).
Connect voltmeter negative (-) lead to ground (-)
wires connection on pump and positive (+) lead to
the “D” terminal (FIG. 44-1). Hold control switch in
the DOWN position. If voltmeter shows a much lower
reading than +12.6 volts DC or a reading of 0 volts,
check for faulty control switch and wiring. Check
battery cable and ground wire connections in pump
assembly and aux battery box (if equipped) for tightness and cleanliness. Check coil resistance to make
sure it is within specifications. Next, connect voltmeter (+) lead to (+) terminal on the “S2” (lowering)
solenoid valve (FIG. 44-1). Voltage may be as low as
10.5 volts DC. If voltmeter shows a much lower reading, or a reading of 0 volts, check for faulty control
switch and wiring, battery cable, ground wire connections in pump assembly, and pump motor.
44
Keep dirt, water and other contaminants from
entering the hydraulic system. Before opening the hydraulic fluid reservoir filler cap, drain
plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the openings from accidental contamination during maintenance.
NOTE: In most cases, you can avoid having to
manually bleed hydraulic system by
correctly positioning Liftgate platform before
disconnecting any lifting cylinder high pressure hydraulic lines.
4. Make sure platform is on the ground. Check the
flow control valve as follows. Remove lowering
solenoid valve and flow control valve (FIG. 451). Ensure the flow control valve operates with
a smooth spring-loaded action. Check for debris
inside the valve. Clean or replace the flow control
valve, if necessary. Reinstall flow control valve (if
good) or a replacement.
FLOW CONTROL
VALVE
COIL
VALVE
CARTRIDGE
NUT
FIG. 45-1
CAUTION
To prevent damage to flow control valve, do not
disassemble the valve.
5. Check the lowering solenoid valve as follows.
Check if filtering screen is plugged. Clean
carefully if required. Push on the plunger in
the valve by inserting small screwdriver in the
open end (FIG. 45-2). If the plunger does not
move with a smooth, spring-loaded action (approximately 1/8”), replace the valve cartridge.
Reinstall lowering solenoid valve (if good) or
a replacement. Torque valve cartridge to 30
lb-ft and hex nut to 30 lb-in.
45
VALVE CARTRIDGE
1/8”
CHECKING SOLENOID VALVE
FIG. 45-2
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
CAUTION
PLATFORM BEGINS TO LOWER ON LH SIDE,
BUT WILL NOT LOWER ON RH SIDE
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
1. Check for battery voltage at the hydraulic lock LOCK VALVE
as follows. Disconnect wiring harness from coil
on the lock valve (FIG. 46-1). Then, connect
voltmeter (+) and (-) leads to connector contacts 1 and 2 on the wiring harness (FIG. 46-2).
Hold control switch in the DOWN position just
long enough to get a reading. Voltmeter should
read at least 11 volts DC. If voltage reading is
lower or “0”, go to step 4.
CONNECTOR
WIRING
HARNESS
LOCK VALVE WIRING
HARNESS CONNECTOR
FIG. 46-1
2 (-)
1 (+)
CONNECTOR
WIRING
HARNESS
MEASURING VOLTAGE AT LOCK VALVE
WIRING HARNESS CONNECTOR
FIG. 46-2
2. Connect ohmmeter (+) and (-) leads
to connector contacts 1 and 2 on the
coil (FIG. 46-3). Ohmmeter should
read about 7 to 8 ohms. If ohms
reading is higher or lower, replace
the coil on hydraulic lock valve.
COIL
CONNECTOR
LOCK VALVE
2
MEASURING COIL RESISTANCE
FIG. 46-3
46
1
CAUTION
Keep dirt, water and other contaminants from
entering the hydraulic system. Before opening the hydraulic fluid reservoir filler cap, drain
plug and hydraulic lines, clean up contaminants that can get in the openings. Also, protect the openings from accidental contamination during maintenance.
3. Suport the platform to prevent it from dropping. Remove solenoid valve (FIG. 47-1).
Ensure the valve operates with a smooth
spring-loaded action (FIG. 47-2). Check
for debris inside the valve. If necessary,
clean or replace the cartridge valve. Reinstall cartridge valve (if good) or install a
replacement.
COIL
VALVE
CARTRIDGE
REMOVING SOLENOID VALVE
FIG. 47-1
VALVE CARTRIDGE
1/8”
CHECKING SOLENOID VALVE
FIG. 47-2
LONG SIDE OF
HOLDER FLATS
BUTT AGAINST
COVER
4. Unfasten and remove pump cover
(FIG. 47-3).
POWER UNIT
(REF)
PUMP
COVER
FLAT
WASHER
(2 PLACES)
KNOB
(2 PLACES)
REMOVING PUMP COVER
FIG. 47-3
47
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
NUT
PLATFORM BEGINS TO LOWER ON LH SIDE,
BUT WILL NOT LOWER ON RH SIDE - Continued
LOCK VALVE
WIRING HARNESS
(REF)
5. Disconnect white wire from the “S2”
(lowering) solenoid valve (FIG. 48-1). Do
resistance checks on the lock valve wiring harness as follows.
WHITE WIRE
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
• Connect ohmmeter (+) and (-)
leads to the black wire and contact 1
on the wiring harness connector
(FIG. 48-2). Reading should be 0.5
ohm or less.
NOTE: Ensure ground bolt and
ground wiring connections on
the pump are clean and tight
(FIG. 48-1).
“S2”
(LOWERING)
SOLENOID
VALVE
DISCONNECTING LOCK VALVE WIRING
FROM LOWERING SOLENOID VALVE
FIG. 48-1
• Connect ohmmeter (+) and (-) leads
to the white ground wire and con
tact 2 on the wiring harness connector (FIG. 48-2). Reading should be
0.5 ohm or less.
• If any readings are more than
0.5 ohm, check lock valve wiring
harness for crimps or damage. Repair
wiring harness if possible, or replace
the entire lock valve assembly, if necessary.
2
1
CONNECTOR
WIRING
HARNESS
BLACK WIRE (+)
WHITE WIRE (-)
(GROUND)
RING TERMINAL
TO “S2” VALVE
6. Before completing this procedure,
ensure lock valve wiring is reconnected to “S2” (lowering) solenoid
valve, ground bolt, control switch
wire, and lock valve coil.
MEASURING RESISTANCE ON LOCK
VALVE WIRING HARNESS
FIG. 48-2
7. Install and fasten pump cover as
shown in FIG. 49-2. Hand-tighten
the cover knobs.
48
NOTE: If the Liftgate is not damaged, the 1100 psi (lowering) pressure relief valve in
the pump may need to be adjusted as follows.
1. Lower the platform until shackles touch the
ground (FIG. 49-1).
SHACKLE
PLATFORM LOWERED WITH SHACKLES
TOUCHING THE GROUND
FIG. 49-1
LONG SIDE OF
HOLDER FLATS
BUTT AGAINST
COVER
2. Unfasten and remove pump cover
(FIG. 49-2).
POWER UNIT
(REF)
PUMP
COVER
FLAT
WASHER
(2 PLACES)
KNOB
(2 PLACES)
REMOVING/INSTALLING PUMP COVER
FIG. 49-2
49
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
PLATFORM WILL NOT TILT DOWN TO THE GROUND
PLATFORM WILL NOT TILT DOWN TO THE GROUND - Continued
CAUTION
Before disconnecting DOWN line, ensure UP line & elbow
are connected to port A.
11921 Slauson Ave. Santa Fe Springs, CA. 90670 (800) 227-4116 FAX (888) 771-7713
3. Check the 1100 psi relief valve as follows.
With platform on the ground, disconnect
DOWN line from Port “B” and remove elbow (FIG. 50-1). Install 0-3000 psi pressure
gauge in Port “B” (FIG. 50-1). Loosen relief
valve lock nut and hold the control switch in
the DOWN position. Adjust the relief valve
until the gauge reads 1100 psi (FIG. 50-1).
Then, tighten relief valve lock nut. Remove
gauge and reinstall elbow and DOWN line.
PORT
“B”
1100 PSI
RELIEF VALVE
CAUTION
Pump cover must be correctly secured to prevent it from becoming
a hazard. To secure pump cover,
the long side of the holder flats
must butt against pump cover as
shown in the illustration.
DOWN
LINE
PRESSURE
GAUGE
ADJUSTING RELIEF VALVE
FIG. 50-1
LONG SIDE OF
HOLDER FLATS
BUTT AGAINST
COVER
4. Install pump cover as shown in
FIG. 50-2. Hand-tighten the cover
knobs.
POWER UNIT
(REF)
PUMP
COVER
FLAT
WASHER
(2 PLACES)
KNOB
(2 PLACES)
INSTALLING PUMP COVER
FIG. 50-2
50
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