SD-30-4265
®
C-300N/C-500N HYDRAULIC POWER STEERING GEAR
OUTPUT
SHAFT
C-300N
NAME PLATE
OIL RETURN
OIL SUPPLY
OUTPUT
SHAFT
ADJUSTING
SCREW
NAMEPLATE
C-500N
VALVE
BODY
OIL RETURN
OIL
SUPPLY
INPUT
SHAFT
SIDE COVER
ADJUSTING
SCREW
STEERING
LIMITING STEM
PLUG
VALVE BODY
OUTPUT
SHAFT
HOUSING
DESCRIPTION
The Compact 300N and 500N (C-300N/C-500N), Hydraulic
Power Steering Gears are designed for medium and heavy
duty vehicles with front axle weight ratings of 6,000 to 9,000
lbs for the C-300N and up to 15,000 lbs for the C-500N.
They are integral power steering gears incorporating the
mechanical and hydraulic actuation and control components
in a single cast housing which serves as the power cylinder.
The C-300N and C-500N power steering gears are very similar
in appearance with the major difference being that the C500N is proportionately larger than the C-300N.
C-300N
PRESSURE
RELIEF & BYPASS
VALVE CAP NUT
POWER STEERING GEAR
The vehicle’s steering column is coupled to the gear at the
input shaft which transmits steering effort through a
recirculating ball screw (spindle assembly) and piston. The
piston is an integral part of the power assist and also acts
as a steering damper. The direction and degree of power
assist is controlled by a rotary hydraulic valve which is integral
to the input shaft and spindle assembly. An engine driven
hydraulic pump supplies the flow and pressure.
1
SD-30-4265
TABLE OF CONTENTS
DESCRIPTION .............................................................. 1
OPERATION .................................................................. 1
• General ........................................................................ 1
• Mechanical .................................................................. 3
• Hydraulic ..................................................................... 4
• Rotary Control Valve .................................................... 4
• Steering Limiting Valve ................................................ 7
• Pressure Relief Valve ................................................... 8
• Bypass Valve ............................................................... 8
POWER STEERING IDENTIFICATION ......................... 8
PREVENTIVE MAINTENANCE ..................................... 8
• Power Steering Oil ....................................................... 8
• Draining and Filling the System ................................... 8
• Oil Change Intervals .................................................... 8
• Output Shaft Sector Teeth Adjustment .......................... 8
• Output Shaft Boot & Dust Seals ................................... 9
CAUTION NOTE ........................................................... 9
REMOVAL ..................................................................... 9
SPECIAL TOOLS .......................................................... 9
DISASSEMBLY .............................................................11
• General .......................................................................11
• Output Shaft Removal .................................................11
• Piston ........................................................................ 13
• Main Housing & Side Cover ....................................... 15
• Valve Body & Spindle ................................................ 16
• Output Shaft .............................................................. 18
• Pressure Relief & Bypass Valve ................................ 18
• Spindle ...................................................................... 18
CLEANING & INSPECTION ........................................ 19
REASSEMBLY ............................................................. 19
• General ...................................................................... 19
• Valve Body & Spindle ................................................ 19
• Piston ........................................................................ 21
• Housing ..................................................................... 24
• Output Shaft & Side Cover ......................................... 25
ADJUSTMENT ............................................................ 26
• Piston to Output Shaft Gear Backlash ........................ 26
• Stroke Limiting Stem .................................................. 27
ON-VEHICLE POWER STEERING TESTS ................ 27
• Preliminary ................................................................ 28
• Pressure Relief Valve ................................................. 28
• Internal Leakage ........................................................ 28
TECHNICAL DATA ...................................................... 29
ASSEMBLY TORQUE CHART .................................... 29
TROUBLESHOOTING ................................................ 30
2
PISTON OVER OUTPUT SHAFT MOUNTING
(LEFT HAND THREAD SPINDLE)
SPINDLE
ASSEMBLY
INPUT
SHAFT
PISTON UNDER OUTPUT SHAFT MOUNTING
(RIGHT HAND THREAD SPINDLE)
STEERING
WHEEL
OUTPUT
SHAFT
SPINDLE
ASSEMBLY
INPUT
SHAFT
STEERING
WHEEL
PISTON
VEHICLE
RIGHT
TURN
PITMAN
ARM
PITMAN
ARM
PISTON
OUTPUT
SHAFT
VEHICLE
LEFT
TURN
FIGURE 1 - MECHANICAL OPERATION
OPERATION
GENERAL
Both steering gears are composed of mechanical and
hydraulic power assist components.
Actual steering is accomplished mechanically. Effort applied
at the vehicle’s steering wheel results in mechanical
movement within the steering gear which causes the vehicle
to change its direction of travel. The hydraulic power assist
components function solely to reduce the mechanical effort
required to turn the vehicle’s steering wheel. Loss of hydraulic
power will in no way prevent the vehicle from being
maneuvered mechanically, however greater effort will be
required to turn the steering wheel.
MECHANICAL OPERATION
The turning effort exerted by the driver on the steering wheel
is transmitted to the input shaft which is part of the spindle
assembly. The spindle and piston function like a screw and
nut through the action of a chain of recirculating balls that
serve as an interface. Rotation of the spindle causes axial
movement of the piston within the power cylinder. Gear teeth,
cut directly into the piston, mesh with corresponding gear
teeth on the output shaft. As the piston moves, the output
shaft and the attached pitman arm are rotated. Figure 1
Spindle and piston sets are provided with either right or left
hand screw threads. Figure 2 The manner in which the
steering gear is mounted on the vehicle determines of the
thread used. Figures 1, 2 & 3
LEFT HAND
THREAD
INPUT
SHAFT
BALL
SCREW
RIGHT HAND
THREAD
FIGURE 2 - SPINDLE ASSEMBLIES
3
TIE ROD
ARM
TIE
ROD
DRAG
LINK
PITMAN
ARM
STEERING
ARM
SPINDLE
ASSEMBLY
PISTON UNDER
OUTPUT SHAFT
PISTON OVER
OUTPUT SHAFT
FIGURE 3 - POWER STEERING GEAR MOUNTING CONFIGURATION
When the steering gear is mounted on the vehicle in a position
similar to the piston under output shaft illustration in figure
1, the piston and spindle used will have a right hand thread.
A left hand thread is required when the steering gear is
mounted in a position similar to the piston over output
shaft illustration. In either mounting position, a right turn is
accomplished when the input shaft is rotated clockwise and
the output shaft, along with the pitman arm, rotate toward
the rear of the vehicle.
HYDRAULIC OPERATION
GENERAL
Functioning together, the spindle and valve body assemblies
serve as a means of flow and pressure control for the power
assist portion of the steering gear. All hydraulic fluid enters
and exits the power steering gear through lines connected
to the threaded ports in the valve body.
The valve body assembly forms a closure for the housing
and provides a means of retaining the spindle assembly. It
contains a series of circular channels and radial passages
which serve to direct the flow of hydraulic oil into and out of
the rotary control valve in the spindle assembly. In addition,
the valve body can contain an optional pressure relief and
bypass valve. The pressure relief valve ensures that a preset
maximum pressure is not exceeded. It is always set at a
pressure level below that of the power steering pump relief
valve and is intended to limit the power assist to a specific
maximum level. Figure 8
The optional bypass valve is intended to lessen the manual
steering effort required in the event hydraulic pressure is
lost. The bypass valve permits fluid to ‘circulate’ within the
4
steering gear rather than being forced to and from the power
steering pump and reservoir. Figure 9
The spindle assembly rotates on a ball bearing in the bore
of the valve body. The spindle is composed of three major
parts;, the input shaft, torsion bar, and ball screw. One end
of the input shaft is finely splined for connection to the
steering column while the other end has a coarse spline
which mates loosely with a similar spline inside the ball
screw. The coarse splines form mechanical stops which
limit the amount of relative rotation between the ball screw
and input shaft. Six evenly distributed longitudinal grooves
are machined into the outer surface of the input shaft and
correspond to six grooves machined into the bore of the
ball screw. The torsion bar is pinned to the ball screw and
input shaft and forms a spring connection between the two.
With the input shaft inserted into the ball screw the six
grooves of each of these components alternate with each
other and form the hydraulic rotary control valve. Holes on
the outside surface of the ball screw extend into the six
grooves within its bore. Figure 5
These holes allow pressurized oil to enter and exit the two
parts of the rotary control valve. There are three groups of
holes in the ball screw. Each group is made up of three
different size holes which form a diagonal line across the
surface of the ball screw. The largest hole in each group
conducts pressurized oil into the grooves of the rotary
control valve. The second largest hole in each group
conducts oil out of the rotary control valve to the side of the
power piston furthest from the rotary control valve while the
smallest hole conducts oil to the closest side of the piston.
Figures 5 & 6
OUTPUT
SHAFT
SIDE
VIEW
RACK AND
SECTOR GEAR
PISTON
TORSION BAR
BALL SCREW
ROTARY VALVE
SPINDLE
ASSEMBLY
INPUT
SHAFT
HOUSING
STEERING
LIMITING STEM
POPPET
SEAT
END
VIEW
STEERING
LIMITING
STEM
POPPET
VALVE
SEAL AND
BACKUP RING
VALVE
BODY
VALVE NUT
RECIRCULATING
BALLS
NAMEPLATE
STEERING
LIMITING STEM
STEM PLUG
C-500N DETAIL
ROLLER
BEARINGS
DUST DUST BOOT
SEAL
ADJUSTING
SCREW SPACER
ADJUSTING
SCREW
OUTPUT RACK AND
SHAFT SECTOR GEAR
RECIRCULATING
BALLS
PISTON
HOUSING
POPPET VALVE
SEAT
ADJUSTING
SCREW LOCK
NUT
SIDE COVER
BALL TUBE
COVER
BALL TUBE
FIGURE 4 - POWER STEERING GEAR
5
BALL SCREW
(OUTER VALVE ELEMENT)
OIL OUT (RIGHT TURN)
OIL IN
TORSION
BAR PIN
OIL RETURN HOLES
(HIDDEN FROM VIEW)
OIL
RETURN
HOLE
INPUT SHAFT (INNER
OIL OUT LEFT
(FROM
VALVE ELEMENT)
ROTARY PISTON
TURN
VALVE
CAVITY)
GROOVES
STEERING
(6)
STOP
OIL RETURN
SPLINES
HOLES (TO
PIN HOLE TORSION BAR
PUMP RES.)
SPINDLE ASSEMBLY
OIL IN
SUPPLY
BALL SCREW
(ROTARY VALVE
OUTER ELEMENT)
OIL OUT
RIGHT TURN
ROTARY VALVE
LONGITUDINAL
GROOVES (6)
(INSIDE HIDDEN
FROM VIEW)
OIL OUT
LEFT TURN
INPUT SHAFT &
TORSION ASSEMBLY
INPUT SHAFT
(ROTARY VALVE
OIL RETURN (TO
INNER ELEMENT)
PUMP RESERVOIR)
INNER VALVE
OIL OUT RIGHT TURN
ELEMENT GROOVE
OIL RETURN (TO
PUMP RES.)
TORSION BAR PIN
TORSION BAR
OIL IN
OIL OUT SUPPLY
(LEFT TURN)
SPINDLE ASSEMBLY
OUTER VALVE
ELEMENT GROOVE
FIGURE 5 - SPINDLE ASSEMBLY WITH ROTARY VALVE COMPONENTS
ROTARY CONTROL VALVE OPERATION
The rotary control valve is an open center type which allows
a continuous flow of oil (through the longitudinal grooves in
the input shaft and bore of the ball screw) when held in the
neutral position by the torsion bar.
When steering effort is applied, the input shaft and ball screw
tend to turn in unison, however the spring action of the torsion
bar results in the input shaft rotating slightly in advance of
the ball screw. The six pairs of grooves that form the rotary
control valve are displaced from their neutral flow position.
As steering effort increases, so does the amount of
displacement. Depending on the direction steered, the groove
displacement of the input shaft directs hydraulic oil through
the appropriate drilled passages in the ball screw to one
side or the other of the piston. Hydraulic pressure acting
INPUT SHAFT (INNER
BALL SCREW
VALVE ELEMENT)
(OUTER VALVE
ELEMENT)
OIL OIL IN
RETURNING
OIL OUT
FROM RIGHT
TURN SIDE OF (LEFT TURN)
POWER
PISTON
LEFT TURN
FIGURE 8 - ROTARY VALVE OPERATION
6
TO
PUMP
RES.
TO
PUMP
RES.
TO
PUMP
RES.
OIL OUT
RIGHT
TURN
OIL IN
OIL OUT
(LEFT TURN)
NEUTRAL
OIL OUT
RIGHT
TURN
OIL IN
OIL RETURNING
FROM LEFT TURN
SIDE OF POWER
PISTON
RIGHT TURN
EXTREME LEFT TURN POSITION POPPET VALVE OPEN
OUTPUT
SHAFT
RETURN
SIDE OF
PISTON
PISTON
HOUSING
EXTREME RIGHT TURN POSITION POPPET VALVE OPEN
BALL INPUT
SCREW SHAFT
OUTPUT
SHAFT
PISTON
POPPET
VALVE
INPUT
SHAFT
SPINDLE ASSEMBLY
LIMITING
STEM
POPPET VALVE PRESSURIZED SIDE
OF PISTON DURING
PISTON SPRING
LEFT TURN
POPPET SEAT
ADJUSTABLE STEM
O-RING
FIGURE 7 - STEERING LIMITING POPPET VALVE OPERATION
upon the piston surface eliminates much of the piston’s
resistance to movement. Spring force exerted by the torsion
bar causes the ball screw to rotate as piston resistance is
removed. As the ball screw rotates, the relative groove
displacement is eliminated and the rotary valve returns to a
neutral position.
Moderate effort at the steering wheel produces smaller valve
displacements and lower power assist, thus providing good
steering feel. At Increased displacements, the pressure rises
more rapidly giving increased power assistance and quicker
response. Maximum pressure is developed after
approximately 30 displacement giving a direct feel to the
steering. Groove displacement is limited by the clearance
of the stop spline mesh between the input shaft and ball
screw. The splines take up the steering movement while
allowing the torsion bar to hold the groove displacement.
The torsion bar and stop splines form two parallel means of
transmitting the steering torque. When no steering torque
is applied, the torsion bar returns the valve grooves to a
neutral position allowing the pressurized oil to flow to the
return line. Figures 5 & 6.
LIMITING
STEM
PRESSURIZED SIDE
DURING RIGHT TURN
POPPET VALVES
(STEERING LIMITING)
steering linkages and components. Figure 7 When this feature
is incorporated in the C-300N, only one of the two steering
limiting stems is externally adjustable. Both steering limiting
stems in the C-500N are externally adjustable. Figure 4.
PRESSURE RELIEF VALVE OPERATION
The pressure relief valve is an option. Located in the valve
body, the pressure relief valve limits hydraulic pressure
within the power steering gear to a preset maximum. While
the setting of the pressure relief valve may be adjusted to
various levels depending upon part number and application,
it is always set to a pressure lower than the relief valve on
the power steering pump. Figure 8.
OIL
RETURN
CHANNEL
POWER
PRESSURE
RELIEF ADJUSTING
INPUT STEERING
GEAR VALVE
VALVE
SHIMS
SHAFT
HOUSING BODY
PLUG
SPRING
SPRING
SEAT
STEERING LIMITING VALVE OPERATION
In steering gears equipped with steering limiting valve, power
assisted movement of the piston within its bore is limited by
poppet valves installed in both piston faces. As the piston
approaches its extreme travel in either direction, a stem
unseats the steering limiting poppet valve. Some hydraulic
power assist is removed as pressurized oil passes around
the poppet valve to the other side of the piston and to the
return line. Continued movement of the piston will result in
removal of increasing amounts of power assist and cause
increased steering effort. Steering limiting reduces the
maximum power assist that can be transmitted to the axle
PRESSURE
RELIEF VALVE
& PISTON
BYPASS
VALVE
OIL RETURN OIL SUPPLY
PORT
PORT
FIGURE 8 - PRESSURE RELIEF VALVE OPERATION
7
OIL
RETURN
CHANNEL
POWER
INPUT STEERING
GEAR
SHAFT
HOUSING
BENDIX ASSEMBLY
PART NUMBER
VALVE
BODY
SERIAL NUMBER
MONTH ASSEMBLED
(A = JAN., ETC.
VEHICLE
MFG’R
PART
NUMBER
SPRING
BYPASS
VALVE
OIL RETURN OIL SUPPLY
PORT
PORT
FIGURE 9 - BYPASS VALVE OPERATION
BYPASS VALVE OPERATION
The optional bypass valve is located adjacent to the pressure
relief valve in the valve body.
When it is necessary to steer the vehicle without the power
steering pump in operation, the bypass valve permits oil to
flow from the return to the supply passages within the
steering gear. As the power piston moves inside the housing,
oil displaced from one side is transferred to the other through
the bypass valve thus preventing reservoir flooding and
cavitation in the pressure line. Figure 9
POWER STEERING GEAR IDENTIFICATION
A nameplate is attached to the exterior of the housing
generally on one of the mounting lugs. The information found
on the name tag is illustrated
LOCATION OF
MANUFACTURE
YEAR ASSEMBLED
(LAST DIGIT)
POWER STEERING GEAR NAMEPLATE INFORMATION
2. Remove the drain plug (54) and seal washer(53) or
disconnect the return line at the valve body outlet port.
(The outlet port is identified by the arrow which flows out
of the gear.) Turn the steering wheel to the left as far as
it will go. Run the engine for 10 seconds at the most
until the oil is drained from the reservoir and pump. Switch
off the engine and turn the steering wheel backwards
and forwards from full lock to full lock until all the oil is
drained out.
3. Clean the outside of the reservoir. Remove and replace
the old filter element.
4. Fill reservoir full of oil.
5. Turn the engine over with the starter motor. (Must be
done in a manner that the engine does not start.) Add oil
as the level drops to avoid air being drawn into the
system.
6. When the oil level reaches the full mark on the dipstick,
start the engine and turn the steering wheel slowly from
side to side until air bubbles cease to appear in the
reservoir. Refill reservoir to full mark on the dipstick.
7. The oil level should be checked every 2,000 miles. The
correct level is between the minimum and maximum level
marks on the dipstick with the engine stopped.
OIL CHANGE INTERVALS
POWER STEERING OIL
It is recommended that the oil be changed at 40,000 mile
intervals and at the time of rebuild. Beyond its function as
the media for transmitting power, the oil also serves to
lubricate and dissipate heat. Carefully clean, inspect, and
replace if necessary all filter elements in the pump system
including vents and breathers.
It is important that an approved oil be used to ensure proper
operation of the power steering unit. The vehicle
manufacturer’s recommendations should be adhered to.
OUTPUT SHAFT SECTOR TEETH
ADJUSTMENT
PREVENTIVE MAINTENANCE
Once an oil type is in use, it should never be mixed with any
other type. If it should become necessary to change types
of oil, the entire system must be drained following the
procedure below.
DRAINING AND FILLING THE SYSTEM
1. Lift the front axle sufficiently to raise the wheels clear of
the ground.
8
The gear lash or preload between the piston teeth and sector
gear should not require attention in normal service, however
a provision for adjustment is provided.
Adjustment requires that the steering gear be drained and
the pitman arm and input shaft be disconnected from the
vehicle. The adjustment procedure is described at the end
of the assembly section of this manual.
EXTERIOR BOOTS AND DUST SEALS
REMOVING THE POWER STEERING GEAR
Inspect the integrity of the output and input shaft boot and
dust seal. These components prevent contamination from
entering the housing around the shaft. If deterioration is
noted, these components should be replaced. The cavities
between the boots and seals should be filled with special
high temperature grease.
1. Mark or identify the inlet and return lines at the valve
body ports.
IMPORTANT! PLEASE READ AND FOLLOW
THESE INSTRUCTIONS TO AVOID
PERSONAL INJURY OR DEATH:
When working on or around a vehicle, the following general
precautions should be observed at all times.
1. Park the vehicle on a level surface, apply the parking
brakes, and always block the wheels.
2. Stop the engine when working around the vehicle.
3. If the vehicle is equipped with air brakes, make certain
to drain the air pressure from all reservoirs before
beginning ANY work on the vehicle.
2. Drain the system following the instructions presented
under “Preventive Maintenance”. Remove both inlet and
return lines.
3. Disconnect the steering column at the input shaft
following the vehicle manufacturer’s instructions.
4. Disconnect the pitman arm from the vehicle’s steering
linkage using the vehicle manfacturer’s instructions.
CAUTION: If it is necessary to remove the pitman arm
before the steering gear is removed from the vehicle,
DO NOT USE HEAT OR POUND ON THE PITMAN
ARM OR OUTPUT SHAFT as damage can result. Do
not attempt repairs to these components. They must be
replaced if damaged. Use a large gear puller to remove
the pitman arm such as ‘Snap-On’ puller #CG-283 or
Ford part number T64P-3590-F.
4. Following the vehicle manufacturer’s recommended
procedures, deactivate the electrical system in a manner
that removes all electrical power from the vehicle.
5. When working in the engine compartment the engine
should be shut off. Where circumstances require that
the engine be in operation, EXTREME CAUTION should
be used to prevent personal injury resulting from contact
with moving, rotating, leaking, heated, or electrically
charged components.
6. Never connect or disconnect a hose or line containing
pressure; it may whip. Never remove a component or
plug unless you are certain all system pressure has
been depleted.
7. Never exceed recommended pressures and always wear
safety glasses.
8. Do not attempt to install, remove, disassemble or
assemble a component until you have read and
thoroughly understand the recommended procedures.
Use only the proper tools and observe all precautions
pertaining to use of those tools.
9. Use only genuine Bendix replacement parts,
components, and kits. Replacement hardware, tubing,
hose, fittings, etc. should be of equivalent size, type,
and strength as original equipment and be designed
specifically for such applications and systems.
PART NUMBER 106234 (REQUIRED)
SPANNER WRENCH - REQUIRED FOR REMOVAL
AND INSTALLATION OF THE VALVE NUT.
PART NUMBER 297676 (REQUIRED)
SEATING TOOL - REQUIRED TO FORM TEFLON GLIDE RINGS
AND TO INSTALL SPINDLE ASSEMBLY IN VALVE BODY.
PART NUMBER 298077 (OPTIONAL)
PILOTED SCREWDRIVER - USED TO REMOVE AND
INSTALL THE PRESSURE RELIEF VALVE SEAT.
10. Components with stripped threads or damaged parts
should be replaced rather than repaired. Repairs requiring
machining or welding should not be attempted unless
specifically approved and stated by the vehicle or
component manufacturer.
11. Prior to returning the vehicle to service, make certain all
components and systems are restored to their proper
operating condition.
PART NUMBER 106762 (OPTIONAL)
HOLDING FIXTURE - USED TO HOLD THE PISTON AND
VALVE BODY DURING ASSEMBLY AND DISASSEMBLY.
FIGURE 10 - TOOLS FOR ASSEMBLY/DISASSEMBLY
9
42
44
7
C-500N DETAIL OF VALVE
BODY AND STEERING
LIMITING STEM
41
43
21
19
A1
45
46
20
48
47
17
9
51
52
23
22
20
38
13
9
18
16
18
53
17
39
54
21
10
40
19
12
11
14
15
9
7
35
37
29
24
28
36
26
4
1
5
6
9
35
9
28
34
ALTERNATE BALL
RETURN TUBE STYLE
FOR C-300/N/C-500N
29
30
27
31
32
49
10
2
50
8
3
B2
25
26
33
FIGURE 7 - C-300N / C-500N POWER STEERING GEAR
POWER STEERING PARTS LIST
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
Valve Nut
External Dust Seal
Spindle Assembly
Internal Dust Seal
Seal
Ball Cage
Valve Body
Ball Race
Ball
Teflon Ring
O-Ring
O-Ring
Steering Limiting Stem
Seal Ring
O-Ring
Spring
Valve Seat
Sealing Washer
Steering Limiting Stem
O-Ring
Plug
Housing
Piston
Tube Cover
Output Shaft
Rollers
O-Ring
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
Backup Ring
Seal & Backup Ring
Retaining Ring
Side Cover
Nut
Adjusting
Adjusting Screw Spacer
Ball Tube
Retaining Ring
O-Ring
Dust Seal
Dust Boot
Bolt
Adjusting Shims
Pressure Relief Valve Plug
Spring
Sealing Washer
Spring Seat
Valve Piston
Seal Washer
Valve Seat
Bolt
Retaining Ring
Bypass Valve Spring
Bypass Ball Valve
Seal Washer
Drain Plug
5. Remove the steering gear from the vehicle.
SPECIAL TOOLS
Two special tools are required to disassemble/assemble the
C- 300N and C-500N. The tools listed and illustrated here
are useful but not all required. All special tools may be
obtained from authorized Bendix part outlets.
DISASSEMBLY
GENERAL
A high level of cleanliness should be observed at all times
when working on the power steering gear. Clean the exterior
of all parts prior to disassembly.
The following disassembly and assembly procedure is
presented for reference purposes and presupposes that a
major rebuild of the power steering gear is being
undertaken. Several replacement parts and maintenance
kits are available which do not require full disassembly. The
instructions provided with these parts and kits should be
followed in lieu of the instructions presented here.
After removing the power steering gear from the vehicle and
cleaning the outside, secure the power steering gear to the
work bench for disassembly. A large vise with jaw protectors
may be used. Clamp across the mounting bolt bosses. (Do
not overtighten.) Figure 12
OUTPUT SHAFT REMOVAL
1. Remove the external dust boot (2) from the spindle
assembly’s input shaft spline. Figure 13
FIGURE 12 - PREPARATION FOR DISASSEMBLY
FIGURE 13 - REMOVING/INSTALLING INPUT SHAFT DUST
BOOT
FIGURE 14 - VALVE BODY BOLT REMOVAL
11
2. Scribe a line or otherwise mark the relationship of the
valve body to the housing. Using a 19mm wrench remove
the four bolts (40) that secure the valve body (7) to the
housing (22). Figure 14
3. Separate the valve body(7) from the housing (22) by
rotating the output shaft (25) using the pitman arm. It
may be necessary to hold or rotate the input shaft (3)
during this operation. Continue to separate the valve
body from the housing until both O-rings (12) on the
valve body can be seen. Figure 15.
4. Scribe a line or otherwise mark the relationship of the
pitman arm to the output shaft (25), then remove the
pitman arm, then the dust boot (39). Figure 16
FIGURE 15 - SEPARATING VALVE BODY & HOUSING
FIGURE 16 - REMOVING/INSTALLING PITMAN ARM & DUST
BOOT
12
CAUTION: Do not use heat or pound on the pitman arm
or output shaft as damage can result. These components
must be replaced rather than repaired if they are
damaged. Remove any accumulated dirt, grease, grime,
and corrosion from the exposed portion of the output
shaft to facilitate removal through its seals.
FIGURE 17 - SIDE COVER REMOVAL/INSTALLATION
FIGURE 18 - SIDE COVER & ROLLER BEARINGS
5. Loosen and remove the lock nut (32) from adjusting
screw (33) on the side cover(31) using a 19mm wrench.
6. Scribe a line or otherwise mark the relationship of the
side cover (31) to housing (22). Using a 19mm wrench,
remove the four bolts (49) that secure the side cover to
the housing. Figure 17
7. Separate the side cover from the housing by turning the
adjusting screw (33) clockwise with a 7mm socket.
Continue turning the adjusting screw until the side cover
can be removed from the housing (22). When the side
cover is removed from the housing the 17 rollers in the
side cover bearing (26) will fall out loose. These rollers
MUST NOT BE INTERCHANGED with the rollers in the
housing bearing which is identical. Figure 17 & 18.
CAUTION: Do not attempt to remove the outer race of
the roller bearing from the side cover.
8. Install the pitman arm and use it to center the piston(23)
and output shaft (25) gear teeth inside the side cover
opening of the housing. Remove the pitman arm and
then remove the output shaft by tapping gently on the
splined end with a soft mallet.
When the output shaft is removed from the housing, the
17 rollers in the housing bearing (26) will fall out loose.
These rollers MUST NOT BE INTERCHANGED with the
rollers in the side cover bearing which is identical.
CAUTION: Do not attempt to remove the outer race of
the roller bearing from the housing. Figure 19
FIGURE 19 - REMOVING OUTPUT SHAFT
13
PISTON REMOVAL & DISASSEMBLY
9. While preventing rotation of the input shaft end of the
spindle assembly (3), pull the valve body (7) and piston
(23) out of the housing (22). Figure 20
10. Remove the retaining ring (36), ball tube cover (24), the
ball tube (35), and 7 of the 26 balls (9) from the piston(23).
Remove the sealing ring(37) from the piston. Note: Bendix
holding fixture 297678 which is pictured is a convenience
but not a necessity for disassembly. Figures 21 to 24
11. In order to remove the remaining 19 balls (9) from piston,
rotate the input shaft in the direction (clockwise or
counterclockwise) that threads the spindle assembly OUT
OF THE PISTON.
FIGURE 22 - TUBE COVER DISASSEMBLY/ASSEMBLY
FIGURE 20 - PISTON REMOVAL/INSTALLATION
FIG. 23 - DISASSEMBLY/INSTALLATION BALL TUBE & BALLS
FIGURE 21- TUBE COVER DISASSEMBLY/ASSEMBLY
14
FIGURE 24 - BALL TUBE COVER O-RING
SEALING WASHER
ITEM 18
VALVE
SEAT
BALL
ITEM 17
ITEM 9
SEALING WASHER
ITEM 18
SPRING ITEM 16
BALL
ITEM 9
VALVE
SEAT
ITEM 17
PISTON ITEM 23
FIGURE 27 - REMOVING/INSTALLING STEERING LIMITING
COMPONENTS
FIGURE 25 - REMOVING/INSTALLING SPINDLE
Separate the valve body and spindle from the piston.
Check the inside of the piston for any stray balls (9)
that may not have been removed in the operation above.
A total of 26 balls, 7 from the ball tube and 19 from the
piston, should be accounted for. Figure 25
12. Remove the sealing ring (14) and O-ring (15) below it
from the groove in the piston (23). Figure 26
13. If the steering gear is not equipped with a steering limiting
valve feature, disregard steps 13-15. Remove either of
the steering limiting valve seats (17) and sealing washer
(18) from the piston. Either a Phillips or straight blade
screwdriver will be required, depending upon which of
the two styles of body is in use. Figure 27
FIGURE 26 - REMOVING/INSTALLING PISTON SEALING RING
& O-RING
Note: Care must be taken during this operation since
damage to the screwdriver slot will make removal
difficult.
14. Remove one of the two balls (9), the spring (16), then
the remaining ball (9). Referring to the previous step,
remove the remaining steering limiting valve seat (17)
and its sealing washer(18) from the other end of the
piston. Figure 27
HOUSING & SIDE COVER DISASSEMBLY
15. Remove the steering limiting stem protective plug (21)
from the housing. Using a screwdriver remove the stroke
limiting valve stem (19) from the housing and separate
the O-ring (20) from the stem. Figure 28
16. Remove the O-ring (27) from the side cover (31). Remove
the seal (29) and its split nylon backup ring (28) from
FIGURE 28 - REMOVING/INSTALLING STEERING LIMITING
STEM
15
FIGURE 29 - REMOVING INSTALLING SIDE COVER SEAL &
O-RING
FIGURE 31 - REMOVING/INSTALLING HOUSING OUTPUT
SHAFT SEAL
(seal and nylon split ring) may not be used in all steering
gears. A one piece seal is sometimes used instead.
CAUTION: Do not remove the outer race of the roller bearing
from the housing.
VALVE BODY & SPINDLE DISASSEMBLY
19. If the steering gear is not equipped with the steering
limiting feature, this STEP MAY BE DISREGARDED.
Follow the appropriate procedure:
C-300N POWER STEERING GEARS
FIGURE 30 - REMOVING/INSTALLING HOUSING OUTPUT
SHAFT DUST SEAL
the side cover bore. The nylon split ring comes out
separately but is part of the seal (29). Figure 29 Note:
The two piece seal (seal and nylon split ring) may not
be used in all steering gears. A one piece seal is
sometimes used instead.
CAUTION: Do not remove the outer race of the roller
bearing from the side cover.
17. Carefully pry out and remove the dust seal (38) from the
housing (22). Figure 30
18. Reaching through the side cover opening of the housing
(22), remove the output shaft seal (29) and its split nylon
backup ring (28) which comes out separately but is
part of the seal (29). Figure 31 Note: The two piece seal
16
In the C-300N power steering gear, the steering limiting
stem is threaded into a blind hole in the valve body and
is accessible only after the valve body(7) has been
removed from the housing (22). Check the condition and
length of the limiting stem (13) in the valve body (7). The
length of the stem measured from the surface of the
valve body to the tip of the stem should be specified in
the vehicle service manual. If the limiting stem is of the
correct length and in good condition, DO NOT REMOVE
it. The limiting stem can be removed if necessary by
heating the steering limiting stem using a hot air gun to
soften the Loctite compound. Care must be taken to
minimize the amount of heat applied to the stem. DO
NOT OVERHEAT! The stem may be removed by turning
counterclockwise. After removal, clean Loctite residue
from the hole.
Use a M6X1 tap to clean the tapped hole. If M6X1 tap is
not available, hole should be cleaned with solvent and
dried well.
C-500N POWER STEERING GEAR
In the C-500N power steering gear, the steering limiting
stem in the valve body (7) is identical to the one in the
housing (19, 20, 21) and can be removed or adjusted
externally without removal of the valve body (7) from the
housing (22). See the inset in figure 4 and 11.
Remove the steering limiting stem protective plug (21)
from the valve body (7) and using a screw driver, remove
the steering limiting stem (19) and O-ring (20) from the
valve body (7). Separate and discard the O-ring (20)
from the stem (19).
20. Remove the input shaft dust seal (4) from the valve nut
(1). Figure 32
21. With a drift punch, unblock the safety point between
the valve nut (1) and valve body (7). Using Spanner
wrench 106234 loosen and remove the valve nut (1) from
the valve body (7). Figures 33 & 34
22. Grasp the input shaft end of the spindle assembly(3)
and lift the spindle assembly (3), ball cage (6), 17 balls
(9) and one half of the outer race (8) out of the valve
body. Figure 35
FIGURE 32 - INPUT SHAFT DUST SEAL
FIGURE 33 - VALVE NUT TO VALVE BODY SAFETY POINT
FIGURE 35 - REMOVING/INSTALLING SPINDLE ASSEMBLY
FIGURE 34 - VALVE NUT & VALVE BODY
FIGURE 36 - SPINDLE ASSEMBLY BALL BEARING
17
23. Separate the outer race (8), ball cage (6) and 17 balls
(9) from the spindle assembly (3). Figure 36
24. Do not remove the other half of the ball bearing outer
race (8) in the valve body.
OUTPUT SHAFT DISASSEMBLY
27. Remove the retaining ring (30), the adjuster screw spacer
(34) and the adjuster screw (33) from the output shaft
(25). Figure 39
25. Remove the retaining ring (50) and then the seal (5) from
the valve nut (1). Figure 37
26. Remove the two outside O-rings (12) from the valve
body, then remove the three Teflon rings (10) and the
corresponding three O-rings (11) from the spindle bore.
Figure 38
FIGURE 39 - OUTPUT SHAFT & ADJUSTING SCREW
FIGURE 37 - VALVE NUT SEAL
SEAL ITEM 47
SPRING
SPRING SEAT
ITEM 51
ITEM 45
BYPASS
VALVE BALL
ITEM 52
FIGURE 38 - VALVE BODY SEALS & O-RINGS
18
VALVE
PISTON
ITEM 46
SPRING
ITEM 43
SHIMS
ITEM 41
SEALING WASHER
ITEM 44
PLUG
SEAT
ITEM
44
ITEM 48
FIGURE 40 - PRESSURE RELIEF & BYPASS VALVE
COMPONENTS
PRESSURE RELIEF & BYPASS VALVE
DISASSEMBLY
28. If the steering gear is equipped with a pressure relief
valve, begin disassembly by removing the plug (42) and
its sealing washer (44) from the valve body (7). Figure
40.
29. Remove the spring (43), spring seat (45), adjusting shims
(41) and the valve piston (46). Figure 40.
30. Using a wide bladed screwdriver or tool 298077, remove
the valve seat (48) and its sealing washer (47). If the
gear is so equipped, remove the bypass valve spring
(51) and the ball (52).
SPINDLE DISASSEMBLY
CAUTION: Do not attempt disassembly of the spindle
assembly which contains the rotary valve. Individual
replacement parts are NOT available. It must be treated
as a single component.
CLEANING AND INSPECTION
FIGURE 41 - INSTALLING PRESSURE RELIEF SPRING SEAT
CLEANING
Wash all parts individually in clean solvent and dry thoroughly.
All non-metallic parts should be discarded and replaced with
new.
INSPECTION
Parts found broken, cracked, distorted, excessively pitted,
or scored must be replaced. Cause for the replacement of
any part should be investigated and corrected to prevent
reoccurrence.
Visually inspect all parts carefully paying particular attention
to:
1. Bearings and bearing surfaces should not exhibit
brinelling, pitting, spalling or cracks. If, upon inspection,
it is determined that the outer races of the roller bearings
(26) contained in the housing (22) or the side cover (31)
are not serviceable, the entire housing or side cover must
be replaced. If the outer ball bearing race (8) remaining
in the valve body (7) is not serviceable, the entire valve
body must be replaced. Inspect the bearing surfaces of
both the inputs.
2. Gear teeth in the output shaft and piston may show
signs of polishing and slight wear; however, pitting,
spalling, and cracks should not be present.
3. Output and input shaft splines.
4. Check the ball rolling surfaces on the exterior of spindle
and interior of piston for cracks, pitting, spalling and
brinelling.
5. Exterior of piston and interior of housing bore.
Note: Minor scuffing of the piston exterior and housing
bore can be considered normal. If deep scoring is
detected, the affected parts should be replaced as
leakage will occur and steering control and reaction
will be affected. Do not attempt honing or boring of
these parts as leakage rates will increase.
6. Pitman arm.
7. Exterior of housing and its mounting lugs.
8. Valve body and porting.
REASSEMBLY OF THE POWER STEERING
GEAR
GENERAL
To ensure proper operation of the power steering gear, the
following procedure and its sequence should be carefully
followed. Failure to do so may result in damage to the gear
or faulty operation or both.
The appropriate maintenance kits should be obtained prior
to reassembly.
VALVE BODY & SPINDLE REASSEMBLY
1. If the power steering gear is so equipped, install the
bypass valve ball (52) and spring (51) in the valve body
(7). Figure 40.
2. Install the sealing washer (47) around the pressure relief
valve seat (48) and using a large bladed screwdriver or
tool piece number 298077, install both in the valve
body(7). Tighten the valve seat to between 15 and 18
pound feet. Figure 40.
3. Install the pressure relief valve piston (46), spring seat
(45), and spring (43) in the valve body. Figure 41.
CAUTION: The spring seat (45) must be installed as
illustrated in Figure 40. Incorrect installation of the spring
19
base grease. The spindle assembly can be used to
assist in pushing the tool through the bore. Figure 42 &
38
6. Install the two O-rings (12) on the valve body (7). Figure
38
7. Install the ball cage (6) over the input shaft end of the
spindle assembly (3). Using a general purpose lithium
base grease to hold them in place, install the seventeen
balls (9) in the ball cage. Figure 43
8. Install the outer ball bearing race half (8) over the input
shaft end of the spindle assembly (3) and insert the
spindle assembly through Bendix tool 297676. Insert
the spindle and tool into the valve body (3) until tool
completely exits the other side and the seventeen balls
(9) of the bearing assembly are resting against the outer
race (8) in the valve body. Figure 44
9. Position the pressure side of the seal (5) in the bore of
the non-pressure side of the valve nut(1). Carefully drive
the seal into the bore until the retaining ring groove
within the bore is visible. Install the retaining ring (50)
making certain it is completely seated in the groove.
After installing the retaining ring, gently tap the seal (5)
from the opposite side until it rests squarely against the
snap ring (50). Note: The seal (5) can be driven into
the valve body bore using a piece of round brass stock
with a diameter of 1.55 inches. Figure 45
10. Apply Loctite 932 or 567 to the tread of the valve nut (1)
Note: Due to the proximity of the spindle ball bearing,
use extreme care in applying the Loctite to the valve
nut threads and allow adequate cure time. Making
certain not to damage the seal (5), install the valve nut
(1) over the input shaft end of the spindle assembly (3)
and into the valve body (7). Using Bendix tool 106234,
FIGURE 42 - FORMING VALVE BODY TEFLON RING & ORING
seat will result in malfunction of the relief valve and
damage to the valve piston and seat.
4. Install the pressure adjusting shims (41) and the seal
washer (44) on the plug (42). Install the plug in the
valve body and torque to between 66 and 73 pound feet
using a 26mm socket. Note: When installing the
pressure adjusting shims (41) use the shims that were
removed during disassembly. However, if a complete
rebuild of the power steering gear is underway, it may
be necessary to add or subtract shims in order to
properly set the pressure relief valve. Figure 40
5. Install the three O-rings (11) and three Teflon rings (10)
in the appropriate grooves in the valve body(7). Form
(expand) the Teflon rings into their grooves by ‘pushing’
Bendix tool 297676 through the bore of the valve body.
Note: Prelubricate the tool with a light film or lithium
20
FIGURE 43 - INSTALLING SPINDLE ASSY. BALL BEARINGS
FIGURE 44 - INSTALLING SPINDLE ASSEMBLY
torque the valve nut to between 221 and 257 pound feet.
Figure 34
Reset the safety point between the valve nut and valve
body using a drift punch or similarly appropriate tool.
Figure 33
11. If the steering gear was equipped with the steering
limiting feature follow the appropriate stem installation
procedure.
C-300N POWER STEERING GEAR
If it was necessary to remove the limiting stem from the
valve body, install the stem (13) now. Using the dimension
given in the vehicle manufacturer’s maintenance
manual, apply Loctite 222 or 262 to the threads and
screw the limiting stem (13) into the valve body (7) until
the correct stem height is obtained above the valve body
FIGURE 45 - INSTALLING PRESSURE SEAL IN VALVE NUT
surface. IMPORTANT: Use care in applying the
Loctite compound to prevent this material from
coming in contact with other surfaces of the valve
body. Figure 4 & 11
C-500N POWER STEERING GEAR
Using lithium grease, lubricate and install the O-ring
(20) in the groove in the steering limiting stem (19).
Screw the assembled stem and O-ring into the valve
body (7) about 5 or 6 turns. Do not install the plug (21)
in the valve body at this time. Figure 4 & 11 inset
12. Install the dust seal (4) in the valve nut (1) taking care
not to damage the seal. Figure 32 The cavity between
the external dust seal (2), the dust seal(4) and fIuid seal
21
PISTON
ITEM 23
STRIP OF SHEET
METAL OVERLAPPING
ITSELF AND ON TOP
OF GLIDE RING
HOSE
CLAMP
FIGURE 46 - RESHAPING THE PISTON GLIDE RING
(5) should be filled with the high temperature grease
provided in the Bendix maintenance kits.
PISTON REASSEMBLY
13. Install one of the two steering limiting valve seats (17)and
its sealing washer (18), into the piston (23). Insert one
of the two balls(9) then the valve spring (16) into the
piston from the opposite end and install the remaining
ball (9), sealing washer (18), and seat (17) in the piston.
Taking care not to damage the valve seats (17), torque
each to between 88 and 132 pound inches. Figure 27.
14. Install the O-ring (15) into its groove in the piston (23).
Figure 26.
15. Thoroughly heat the glide ring (14) to between 285° and
320° F in preparation for installation on the piston. Note:
DO NOT USE AN OPEN FLAME to heat the glide ring.
A heat lamp or a similar device should be used.
16. Install the heated glide ring (14) over the O-ring (15) in
the piston’s groove (23).
BALL
FEED
OPENING
OLD STYLE
FIGURE 47 - BALL TUBE STYLES
22
NEW STYLE
FIGURE 48 - INSTALLING BALLS IN OLD STYLE BALL
RETURN TUBE
IMPORTANT!
The glide ring should be distorted as little as possible
during installation. Using an automotive piston ring
compression tool or a smooth piece of sheet metal and
an appropriately large screw type hose clamp, reshape
the glide ring into the piston groove. Allow approximately
ten minutes cooling time before removing the
compression tool from the piston. Figure 46.
17. Install the O-ring (37) in its groove in the ball return
opening of the piston (23). Figure 24.
18. CAUTION: The UTMOST care must be taken with the
following steps. Incorrect assembly of this group of parts
can cause damage to the parts and failure of the gear
to operate properly.
Two different style return tubes (35) have been used
for the C-300N and C-500N power steering gears.
Before proceeding further, identify the type of ball return
tube that is being installed.
If the OLD STYLE ball return tube is in use, PROCEED
TO STEP 19. If the NEW STYLE ball return tube is in
use, PROCEED TO STEP 21.
OLD STYLE BALL TUBE
19. Insert the valve body and spindle assembly (3) all the
way into the piston (23) making certain that the stroke
limiting stem (13) is not damaged and that it mates with
the valve seat (17) in the piston (23). Insert nineteen of
the balls (9), one at a time, into one of the recirculating
tube holes in the ball return opening in the piston. Rotate
the input shaft end of the spindle (3) slightly after each
ball is inserted. Rotate the spindle in one direction only
and do not alternate from clockwise to counterclockwise.
Note: When this operation is performed correctly, the
spindle and valve body should screw out of the piston
and the balls inserted in one recirculating tube hole
should appear at the opposite hole. Before proceeding,
make certain the balls are at an equal depth in both
holes of the piston. This will assure correct installation
of the return tube (35). Figure 25.
CAUTION: The utmost care must be taken with these
steps. Incorrect assembly of this group may result in
one or more balls failing inside the piston or coming out
at the top and lodging in the housing.
20. Install the remaining seven balls (9) in the recirculating
tube halves (35), and use lithium base grease to retain
them in the tube. Seat the assembled tube halves (35)
containing the seven balls in the recirculating tube holes
in the piston (23). Lightly grease the sealing surfaces
of the tube cover(24) and install it in the piston making
certain the slot in the underside of the cover mates with
the recirculating tube in the piston. Install the retaining
ring (36) in the piston to secure the tube cover making
certain it is completely seated in its groove. After
assembly, check for smooth rotation of the spindle
assembly in both directions. Figure 21, 22, 24 & 48.
NEW STYLE BALL TUBE
21. Insert the valve body and spindle assembly (3) all the
way into the piston (23) making certain that the steering
limiting stem (13) is not damaged and that it mates with
the valve seat (17) in the piston (23). Pull the valve and
spindle assembly (3) out of the piston (23) about two
inches, MAKING CERTAIN THE STEERING LIMITING
STEM (13) REMAINS ALIGNED WITH VALVE BALL
AND SEAT (17). Make certain the spindle threads will
not interfere with the ball pick-up tabs on the ball tube
(35) when it is inserted into the tube holes in the piston
(23). The spindle’s threads are visible at the bottom of
the tube holes in the piston. Figure 49 Insert the ball
return tube halves (35) all the way into the holes in the
piston. If the ball return tube is properly installed, the
FIGURE 49 - INSTALLING NEW STYLE BALL RETURN TUBE &
BALLS
23
SEAL
ITEM 29
PRESSURE
SEALING LIP
FOR I.D.
BACKUP RING
ITEM 28
PRESSURE
SIDE OF SEAL
BACKUP RING INSTALLED
IN NON-PRESSURE SIDE
OF SEAL
NON-PRESSURE
SIDE OF SEAL
PRESSURE
SEALING LIP
FOR O.D.
FIGURE 50 - DETAIL OF SEAL & BACKUP RING ASSY.
FIGURE 52 - INSTALLING STEERING LIMITING STEM
FIGURE 53 - INSTALLING OUTPUT SHAFT ROLLERS IN
HOUSING
spindle should rotate freely and will begin to thread into
or out of the piston depending upon the direction of
spindle rotation.
Note: Hold the ball return tube firmly in place when rotating
the spindle.
22. While FIRMLY HOLDING THE BALL TUBE (35) IN
PLACE insert as many of the balls(9) through the
opening in the ball tube as possible. Rotate the input
shaft (3) slightly to make room for each ball that is
inserted. (Note: As the spindle is rotated the ball tube
may tend to rise out of the holes in the piston.)
Continue to insert balls until ALL TWENTY-SIX HAVE
BEEN INSTALLED. Figure 49 Lightly grease the sealing
surfaces of the tube cover(24) and install it in the piston
FIGURE 51 - INSTALLING HOUSING OUTPUT SHAFT SEAL
24
making certain the slot in the underside of the cover
mates with the recirculating tube in the piston. Install
the retaining ring (36) in the piston to secure the tube
cover making certain it is completely seated in its groove.
After assembly, check for smooth rotation of the spindle
assembly in both directions. Figures 21, 22, 24
HOUSING REASSEMBLY
23. Reaching through the side cover opening of the housing
(22), install the seal (29) with its pressure side toward
the INTERIOR of the housing. Note: Do not distort this
‘flexible’ seal any more than is necessary for
installation, Install the split nylon backup ring (28), which
is a separate part of the seal (29), by winding it into the
groove formed by the backside (non-pressure side) of
the seal and the housing. Make certain the split ring is
completely seated and that the diagonal split surfaces
of the ring mate properly. Note: This seal prevents
pressurized fluid from leaking out of the housing around
the output shaft. Figures 50 & 51.
Note: The two piece seal (seal and nylon split ring)
may not be used in all steering gears. A one piece
seal is sometimes used instead.
24. Install the dust seal (38) in the housing (22) with its
sealing lip toward the OUTSIDE of the housing. Note:
This seal is intended to prevent water and dirt from
entering the housing. Figure 30.
25. Install the O-ring (20) in the groove around the steering
limiting stem (19) and screw the stem(19) and screw
the stem (19) into the housing (22) about five or six full
turns. Figure 52
26. Install the seventeen rollers of the bearing (26) in the
outer race contained in the housing (22). Use a heavy
coating of lithium grease to hold the rollers in place.
IMPORTANT: The seventeen rollers that are
installed must be the same rollers that were
removed from this bearing during ‘Disassembly’.
Figure 53
27. Align the steering limiting stem (13) in the valve body
(7) with the steering limiting valve seat (17) in the piston
(23). Insert the piston (23) into the housing (22) so that
the rack teeth of the piston are visible in the side cover
opening in the housing. (Figures 20 & 53) Make certain
that the valve body is oriented in the housing so that the
marks made during disassembly align. Slide the piston
and valve body assembly completely into the housing
taking SPECIAL CARE not to damage the piston glide
ring (14) and the valve body O-rings(12). Secure the
valve body(7) to the housing (22) using four bolts (40).
Torque the bolts to 81-88 pound feet for the C-300N
and 92-99 pound feet for the C-500N using a 19mm
socket and socket and torque wrench. Rotate the input
shaft of the spindle (3) until the rack teeth of the piston
are centered in the side cover opening in the housing.
Figure 53
OUTPUT SHAFT & SIDE COVER REASSEMBLY
28. Install the shim washer (34) over the adjusting screw
(33) and secure both in the output shaft (25) using the
retaining ring (30). The maximum end play permitted
for these parts is .002", however, binding should to
occur. If end play is excessive, it may be necessary to
install a different shim washer (34). The shim washer is
available in eight different thicknesses to provide the
proper end play. Figure 39
29. Install the seal (29) in the side cover (31) with its
pressure side toward the outer race of the side cover
roller bearing (26). Note: This seal prevents fluid leakage
around the output shaft. Do not distort this ‘flexible’ seal
more than is necessary for installation. Install the split
nylon backup ring, (28) which is a separate part of the
seal, by winding’ it into the groove formed by side cover
and the backside of the seal (29). Make certain the split
ring is completely seated and that the diagonal split
surfaces of the ring mate properly. Install the O-ring
(27) in its groove in the side cover(31). Figure 29 & 50
Note: The two piece seal (seal and nylon split ring) may
not be used in all steering gears. A one piece seal is
sometimes used instead.
FIGURE 54 - INSTALLING ASSEMBLED OUTPUT & SIDE
COVER
30. Install the seventeen rollers of the bearing (26) in the
outer race contained in the side cover (31). Use a heavy
coating of lithium grease to hold the rollers in place.
IMPORTANT: The seventeen rollers that are installed
must be the same rollers that were removed from
this bearing during ‘Disassembly’. Refer to Figure 18
25
travels through the mid point of its travel and should
disappear as the piston moves past the midpoint.
To obtain the adjustment stated above, make certain the
adjusting screw (33) is turned counterclockwise as far
as it will go. Rotate the input shaft as far as possible in
both directions. Count the total revolutions in either
direction and at the same time measure the average
torque to rotate the shaft.
To obtain the proper preload adjustment, rotate the input
shaft 180° in both directions past the midpoint of piston
travel. (The midpoint of piston travel is approximately
one half the number of input shaft revolutions possible
in a single direction.)
FIGURE 55 - INSTALLING ADJUSTING SCREW LOCK NUT
31. Lightly lubricate the seals(29) contained in both the
housing (22) and side cover(31) with lithium grease.
Lubricate the sealing surface of the output shaft (25)
on the adjusting screw end only. Using a 7mm socket
wrench install the assembled side cover (31) on the
output shaft adjuster screw (33) and screw it on as far
as it will go, then back it off 1/8 of a turn. Figure 54
32. Prior to inserting the assembled side cover and output
shaft (25) into the housing (22), wrap a single layer of
masking tape around the splines to protect the housing
seal (29). Lubricate the exterior of the tape with a lithium
grease and insert the shaft and side cover assembly
into the housing with a twisting motion. Remove the
masking tape from the output shaft splines. Figure 54
33. Secure the side cover to the housing using four bolts
(49). Make certain that the side cover is positioned so
that the marks made during disassembly are aligned.
Torque the bolts to between 81 and 88 pound feet for
the C-300N and 92-99 pound feet for the C-500N, using
a 19mm socket and torque wrench. Pack the cavity of
exterior dust boot (39) with high temperature grease
provided in the Bendix maintenance kit, then install the
exterior dust boot (39) on the output shaft. Refer to
Figures 13 & 16
PRELOAD ADJUSTMENT
ADJUSTING THE PISTON TO OUTPUT SHAFT
GEAR PRELOAD
34. The piston and output shaft gear preload is correct when
a 4 to 18 pound-inch increase in torque is noted at the
input shaft as it is rotated and the piston passes through
the midpoint of its total travel in the housing. The torque
increase at the input shaft will occur only as the piston
26
Each time the direction of input shaft rotation is changed,
turn the output shaft adjustment screw (33) clockwise
1/8 to 1/4 turn. Continue this procedure until a 4 to 18
pound inch increase is noted in the torque required to
rotate the input shaft.
35. When the adjustment is correct, install lock nut (33)
and apply a torque of 74 to 88 pound feet with a 19mm
crow foot and torque wrench while holding the
adjustment screw in position with the 7mm socket and
torque wrench. Figure 55
36. After all the described steps have been performed, check
that the power steering unit runs smoothly throughout
its entire motion and that the gear preload at the center
position is as prescribed in Step 34.
37. Install the power steering gear on the vehicle. Fill gear
with fluid per vehicle manufacturer’s procedure. Test
for flow, leakage and the pressure relief valve setting (if
applicable) as well as setting the stroke limiting (if
applicable).
STEERING LIMITING STEM ADJUSTMENT
GENERAL
The function of the optional steering limiting feature is
to relieve most of the hydraulic power assist prior to the
piston (23) reaching the end of its full travel in either
direction. This ensures that the axle stops are not
impacted with full hydraulic assist when a full wheel cut
is made in either direction.
The C-300N has two adjustable steering limiting stems
(13 & 19) of which only one (19) is externally adjustable.
The internal adjustable stem (13) must be preset during
assembly to meet vehicle requirements.
The C-500N has two externally adjustable steering limiting
stems (19), one located in the housing (22) (like the
C-300N) and one in the valve body (7). Both stems are
adjusted externally after mounting the C-500N on the
vehicle.
The following instructions are for the externally adjustable
steering limiting stem.
1. Adjust the axle stops using the vehicle manufacturer’s
specifications.
2. Install a pressure gauge or gauge and flow meter
combination in the pressure (supply) line between the
power steering pump and steering gear. Figure 56. Note:
If a shut off valve is part of the gauge or gauge/flow
meter, make certain the valve is open.
Caution: During the procedure that follows, use
extreme care not to operate the power steering pump
at its relief valve pressure for more than a few seconds
at a time. Extended operation at pump relief pressure
will result in excessive heat and subsequent damage
to the system. A thermometer installed in the pump
reservoir will allow temperature checks to assure the
maximum pump and gear temperatures are not
exceeded.
3. Start the engine and gently turn the steering wheel to
the axle stop in both directions while observing the
THERMOMETER
POWER
STEERING GEAR
B. Gauge pressure does not drop prior to axle stop
contact in either turning direction, and pump or gear
relief pressure is noted upon axle stop contact.
If the steering gear being adjusted is a C-300N, this
reaction indicated the internally adjustable steering
limiting stem is improperly adjusted, or broken, or
the steering limiting valve (9 & 17) is malfunctioning.
The C-300N must be removed and disassembled.
If the steering gear being adjusted is a C-500N, this
is the desired reaction. Proceed to Step 4.
C. If gauge pressure drops prior to axle stop contact
both directions, turn the externally adjustable
steering limiting stem counter-clockwise and repeat
the test until reaction ’A’ is obtained for C-300N or
reaction ‘B’ is obtained for C-500N.
4. Return the steering to a neutral straight ahead position
and turn the externally adjustable steering limiting stem
clockwise to its full travel.
5. Gently turn the steering wheel in the direction effected
by the externally adjustable steering limiting stem until
the axle stop is contacted. Pressure registered on the
gauge should be relatively low.
OIL
RESERVOIR
GAUGE
POWER STEERING
PUMP
If the steering gear being adjusted is a C-500N, make
certain that both externally adjustable steering
limiting stems are adjusted out (counter clockwise)
to within 5 turns of being removed, then retest.
FLOW METER
SHUTOFF
VALVE
FIGURE 56 - FLOW METER & PRESSURE GAUGE
INSTALLATION
pressure gauge and the direction of the wheel cut (right
or left). Read the possible reactions described below
and take the appropriate action.
A. Gauge pressure drops noticeably just prior to the
steering mechanism contacting the axle stop in one
turning direction only. In the opposite steering
direction, gauge pressure increases to pump or gear
relief pressure as the steering mechanism contacts
the axle stop.
If the steering gear being adjusted is a C-300N, this
is the desired reaction and indicates the turning
direction controlled by the externally adjustable
steering limiting stem. The turning direction that
registers pump relief is the one controlled by the
externally adjustable steering limiting stem. Proceed
to Step 4.
With the steering wheel held to maintain axle stop
contact, turn the stroke limiting stem counterclockwise
until the gauge pressure JUST begins to rise or until
the gauge pressure specified by the vehicle
manufacturer is obtained.
Note: A rise in pressure on the gauge while turning
the stroke limiting stem counterclockwise indicates
that the stroke limiting valve is beginning to close.
Continued turning of the stem will cause the valve to
close and the pressure to rise until the valve is
PART NUMBER 106773
PRESSURE RELIEF VALVE TEST PLUG ASSEMBLY
FIGURE 57 - PRESSURE RELIEF VALVE TEST PLUG
ASSEMBLY
completely closed and the pressure rises to the gear
or pump relief setting.)
6. After adjustment of the stroke limiting is complete, install
the plug(s) (21) in the stem bore(s).
27
ON-VEHICLE POWER STEERING TESTS
PRELIMINARY
1. Install a flow meter, pressure gauge (3,000 p.s.i.
minimum) and a shut off valve in the pressure line between
the power steering pump and gears illustrated in the
figure. MAKE CERTAIN THE SHUTOFF VALVE IS
OPEN.
2. Install a thermometer capable of reading 300°F in the
power steering pump reservoir.
3. Turn the vehicle’s front wheels to the straight ahead
position, engage the parking brake and place the
transmission gear selector in neutral.
4. Perform the power steering pump performance tests
specified by the vehicle manufacturer. Make certain
that system back pressure, maximum and minimum pump
flow and pump relief pressure all meet specified
requirements.
TESTING THE POWER STEERING GEAR
PRESSURE RELIEF VALVE
Note: Disregard this test if the steering gear is not
equipped with an optional pressure relief valve.
1. To prevent the operation of the steering limiting valves, if
the gear is so equipped, place a steel spacer block
between the axle stop and the adjusting screw. The block
should be a minimum of one inch thick and long enough
to be inserted without danger of pinching fingers. Keep
fingers clear of pinch points and be sure block is square
to points of contact.
WARNING! - Failure to follow these instructions can
result in serious injury or damage to the equipment.
2. Check fluid temperature in the reservoir. Thermometer
reading should be approximately 130° at start of the
test and the shut off valve on the flow meter must be
totally open.
Note: Refer to Preliminary Instructions section of
the service data.
3. Turn the steering wheel until the axle stop contacts the
spacer block. Apply sufficient torque to the steering
wheel to ensure the power steering gear control valve is
completely open in the direction of the turn. At this time
the pressure gauge will read the gear pressure relief
setting. If the pressure reading is within plus or minus
60 p.s.i. of the pressure specified in the vehicle manual,
the pressure relief valve is operating properly. If the
pressure is outside of this range, the pressure relief
valve should be adjusted or repaired as necessary.
CAUTION: When running this test, do not hold the
torque on the steering wheel for more than 5 seconds
beyond the time the pressure relief setting has been
28
reached. It may damage the unit or cause the
temperature of the oil to rise beyond 200°.
TESTING THE POWER STEERING GEAR FOR INTERNAL
LEAKAGE
General Note: Excessive internal leakage past seals and
O-rings will generally be manifested by an increase in
steering effort especially when steering quickly to the
right or left. The tests that follow can be used to confirm
this symptom.
1. If the power steering gear is equipped with a pressure
relief valve, it will be necessary to temporarily change
its setting to a pressure above that of the power steering
pump relief valve. Only the Bendix pressure relief
valve test pump assembly 106773 (Figure 57) must
be used.
To install the plug assembly:
A. With the engine stopped, remove the pressure relief
valve plug (42) and its sealing washer (44).
B. Install approximately .030" to .060" additional shims
(41) in the socket portion of the plug (42).
C. Reinstall the plug (42) and its seal washer (44) along
with the additional shims (41). Torque the plug to
between 66 and 73 pound feet using a 26mm socket.
2. To prevent the operation of the steering limiting valves, if
the gear is so equipped, place a steel spacer block
between the axle stop and the adjusting screw. The block
should be a minimum of one inch thick and long enough
to be inserted without danger of pinching fingers. Keep
fingers clear of pinch points and be sure block is square
to points of contact.
WARNING! - Failure to follow these instructions can
result in serious injury or damage to the equipment.
3. Run the engine at idle. Turn the steering wheel until the
axle stop contacts the spacer block. Apply a sufficient
torque to the steering wheel to ensure the power steering
gear control valve is completely open in the direction of
the turn. Observe the following:
A. Gauge pressure should read the same as the power
steering pump relief pressure.
B. With system pressure at pump relief, read the flow
meter. If a flow greater than 1.6 quarts per minute
(0.40 GPM) is noted, internal leakage is excessive
and the steering gear requires repair.
CAUTION:
When running this test, do not hold the torque on the steering
wheel for more than 5 seconds beyond the time the
pressure relief setting has been reached. It may damage
the unit or cause the temperature of the oil to raise beyond
200°.
4. Repeat Step 3 - turning the steering wheel in the opposite
direction.
5. With the engine off remove the pressure relief test plug
assembly (106773). Reinstall the spring (43). Install a
new (unused) sealing washer (44) on the pressure relief
valve plug (42) then install the adjusting shims (41) in
the plug. Install the plug (42) in the valve body(7) and
torque to 66-73 pound feet.
Step 5 must be completed before placing the vehicle back
in service.
TECHNICAL DATA
Steering wheel revolutions for
90° rotation of output shaft
Maximum output
shaft rotation (Note 1)
Maximum output
shaft torque with 1992 p.s.i.
(140 Kg/C M2) power assist
Power steering fluid
TROUBLESHOOTING
PRELIMINARY CHECKS
IMPORTANT:
Steering ratio
(input to output shaft)
that optional feature is incorporated. Maximum
allowable pressure for the C-300N is 2102 psi (145
bar) and for the C-500N is the same.
Note 3: The pressure drop and flow rate are interrelated
and application specific. Consult the vehicle
manufacturer’s maintenance manual for this
information.
C-300N C-500N
21.2:1
21:1
5.3
5.25
95° Max. Travel
1985 lb. ft.
(270 mdaN)
90
3767
(510)
DEXRON 11 ATF
Maximum working temperature
248°F (120°C)
Maximum peak temperature
302°F (150°C)
Maximum allowable pressure
See Note 2
(144 Kg/C M2)
Maximum pressure drop
in the return line
See Note 3
Maximum normal flow
See Note 3
Note 1: Maximum rotation is specified, maximum power
assisted rotation is less when steering limiting
optional feature is incorporated.
Note 2: Maximum working pressure is determined by the
pressure setting of the pressure relief valve when
Before proceeding to the troubleshooting headings, it is
strongly recommended that some preliminary checks be
made and a test ride be taken to eliminate unnecessary
work.
1. Check for proper and equal tire inflation on the steering
axle. Note any abnormal tire wear which may be
attributable to front end alignment.
2. Make certain the power steering reservoir oil level is
correct.
3. Make certain the power steering pump belt is not slipping.
4. Visually inspect the following components for obvious
damage, misadjustment and possible binding.
A. steering column and universals or couplings.
B. steering arms, tie rods, tie rod ends and knuckles.
C. general looseness in the steering linkages.
5. Check hoses for sharp bends, kinks and proper
size.
The most common faults may be grouped under the following
headings:
1. Power steering does not operate.
2. The power steering is stiff in one direction and normal in
the other.
3. The power steering tends to turn itself when the engine
is started.
4. Excessive free play at the steering wheel.
5. The power steering operates normally but is intermittently
hard.
6. Oil leaks.
7. The power steering is stiff when turning the steering wheel
quickly.
8. The power steering does not return correctly.
9. The power steering operates but with noise, turbulence
or vibration.
TORQUE CHART
Item
C-300N
Valve Body Bolts (Item 40)
81-88 Pound Feet
Side Cover Bolts (Item 49)
81-88 Pound Feet
Side Cover Adjusting Screw Lock Nut (Item 32)
74-78 Pound Feet
Valve Body Valve Nut (Item 1)
221-257 Pound Feet
Steering Limiting Valve Seat (Item 17)
8-11 Pound Feet
Pressure Relief Valve Seat (Item 48)
15-18 Pound Feet
Pressure Relief Valve Plug (Item 42)
66-73 Pound Feet
Drain Plug (Item 54)
37-47 Pound Feet
C-500N
92-99 Pound Feet
92-99 Pound Feet
74-78 Pound Feet
221-257 Pound Feet
8-11 Pound Feet
15-18 Pound Feet
66-73 Pound Feet
37-47 Pound Feet
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SYMPTOM
1. Power steering does not
operate or manual steering
effort is excessive.
TROUBLESHOOTING CHART
CAUSE
1. Low oil level.
1. Check oil level.
2. Air in system.
2. Check that there are no leaks,
bleed and top up with oil.
3. Check pump performance to
specification.
4. Remove lines and clean.
3. The pressure pump does not supply
an adequate flow or pressure.
4. Obstruction in the oil reservoir
outlet or inlet.
5. Internal leakage in power
steering gear piston.
6. Mechanical faults in vehicle
steering members not belonging
to power steering gear.
7. Low pressure in front tires.
8. Relief valve opens at low pressure.
2. Steering effort greater in
one direction than in the
other.
REMEDY
1. Low or no pressure applied to one
side of power steering piston.
2. Faulty operation of the rotary valve.
5. Verify by test and repair
as necessary.
6. Overhaul and test in accordance
with vehicle service manual.
7. Inflate tires to correct pressure.
8. Verify by test & repair as
necessary.
1. Verify be test and repair as
necessary.
3. Mechanical fault in vehicle steering
members not belonging to power
steering units.
2. Replace piston and spindle
assembly.
3. Overhaul and check in
accordance with vehicle service
manual.
3. Power steering tends to
turn by itself when
engine is running.
1. Faulty rotary valve.
1. Replace piston &spindle assembly
4. Excessive free play in
steering wheel.
1. Power steering housing or housing
support loose.
2. Excessive play between output shaft
sector teeth and piston.
1. Retighten mounting bolts.
3. Loose or worn ball studs in steering
linkage. Loose or worn intermediate
steering shafts.
2. Adjust gear lash. If all adjustment
has been used, replace output
shaft and spindle assembly.
3. Mechanical faults in vehicle
steering members. See vehicle
manual.
5. Power steering operates
normally but is
intermittently hard.
1. Dirty oil.
2. Low oil level.
3. Faulty operation pressure pump.
specification. Overhaul by
authorized workshop if required.
1. Change oil.
2. Check oil level.
3. Check pump to performance
6. Oil leaks
1. Hose or hose connections.
2. Faulty or incorrectly installed
seal rings.
1. Tighten or replace.
2. Clean & dry the outside of the
power steering body and take the
vehicle out on test to locate the
leak.
30
SYMPTOM
7. Power steering stiff
when turning steering
wheel quickly.
TROUBLESHOOTING CHART
CAUSE
1. Restricted hose.
2. Incorrect hose size.
3. Faulty operation of hydraulic pump.
4. Internal leakage in power steering
gear.
8. Power steering does not
return correctly.
9. Power steering operates
but with noise,
turbulence or vibration
1. Low tire pressure.
2. Front axle assembly deformed as a
result of accident or breakdown in
the rotary valve unit.
3. Bind in intermediate shafts.
4. Lower steering gear parts deformed
as a result of accident or breakdown
in the rotary valve unit.
1. Reservoir oil level low.
2. Piping contacting part of the bodywork, causing vibrations (particularly
the pressure feed line).
3. Unsuitable oil.
4. Oil reservoir filter blocked.
5. Power steering pump.
REMEDY
1. Replace incorrect or
unserviceable hoses.
2. Replace incorrect or
unserviceable hoses.
3. Check pump to performance
specifications. Overhaul by
authorized workshop.
4. Verify by test; repair if necessary.
1. Inflate tires to correct pressure.
2. Lubricate front axle assembly.
Check for damaged or worn parts.
3. Determine cause and correct.
4. Replace the piston and spindle
assembly.
1. Fill up to level.
2. Space pipe from bodywork, if not
possible, insulate with a rubber
spacer.
3. Drain oil and fill up with
recommended grade.
4. Replace filter.
5. Repair or replace.
BW2600 © 2002 Bendix Commercial Vehicle Systems LLC All rights reserved. 3/2002 Printed in U.S.A.
31