®
COMPACT 500 INTEGRAL HYDRAULIC POWER STEERING GEAR
FOR FORD MOTOR CO. CARGO VEHICLES
SD-30-4250
I. DESCRIPTION
The Compact 500 Hydraulic Power Steering gear is designed
for heavy duty vehicles with front axle weight ratings of up to
15,000 lbs. It is an integral power steering gear incorporating
the mechanical and hydraulic actuation and control
components in a single cast housing which serves as the
power cylinder.
The vehicles steering column is coupled to the gear at the
input shaft which transmits steering effort through a
recirculating ball screw and piston nut. The piston nut is an
integral part of the power assist piston 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 supplied by an engine driven hydraulic
pump.
This valve design assures light, responsive steering while
maintaining a mechanical connection between the steering
column and the ball screw.
II. OPERATION
GENERAL
The C-500 integral power steering gear is composed both of
mechanical steering components and hydraulic power assist
components. Actual steering is accomplished mechanically.
Effort applied at the vehicles 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 effort
required to turn the vehicles 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 ball
screw assembly. The ball screw and piston nut function like
1
TABLE OF CONTENTS
Page No.
I. DESCRIPTION 2
II. OPERATION 2-4
1. General 2
2. Mechanical Parts 2
3. Hydraulic Parts 2, 3
4. Power Steering Identification 4
III. TECHNICAL DATA 4
IV. PREVENTIVE MAINTENANCE 4-5
1. Power Steering Oil 4
2. Draining and Filling the System 4
3. Change Intervals 5
4. Output Shaft Sector Teeth Adjustment 5
5. Output Shaft Boot Seal 5
V. CAUTION NOTE 5
VI. REMOVAL 6
VII. SPECIAL TOOL REQUIREMENTS 6-7
VIII. DISASSEMBLY 9-16
1. General 9-11
2. Piston 11-13
3. Main housing 13
4. Side cover 13
5. Valve Body 14
6. Pressure Relief Valve 15
7. Output shaft 16
8. Cleaning 16
9. Inspection 16
IX. REASSEMBLY 16-23
1. Valve body 16-17
2. Spindle assembly 17-18
3. Piston 19-20
4. Main housing 21
5. Housing and valve body 21
6. Output shaft 21
7. Side cover 22
8. Housing and side cover 23
9. Adjustment of output shaft backlash 23
X. PRESSURE, FLOW & LEAKAGE TESTS 23-25
1. Relief Pressure Test - Power Steering Pump 24
2. Relief Pressure Test - Power Steering Gear 24-25
XI. TROUBLESHOOTING 25-27
2
LEFT TURN RIGHT TURN
BALL SCREW
PISTON NUT
RECIRCULATING
BALLS
PITMAN ARM
POWER CYLINDER
FIGURE 1 - MECHANICAL OPERATION
PISTON NUT
RECIRCULATING
a screw and nut through the action of the chain of
recirculating balls that serve as an interface. Rotation of
the ball screw causes axial movement of the piston within
the power cylinder. Gear teeth cut directly into the piston
mesh with corresponding sector gear teeth on the output
shaft and as the piston moves, the output shaft and attached
pitman arm are rotated.
HYDRAULIC OPERATION
The driven end of the ball screw rotates on a ball bearing
contained in the valve body. Hydraulic pressure enters and
exits the power steering gear through lines connected to
threaded ports in the valve body. A pressure relief valve
contained in the valve body prevents overpressurization of
the power steering gear.
Hydraulic pressure in excess of the setting of the relief valve
causes the valve to open a channel to the reservoir return
side of the gear.
STEERING
WHEEL
SPINDLE
BALLS
PITMAN
ARM
The coarse splines form mechanical stops which limit the
amount of relative rotation between the ball screw and input
shaft. A torsion bar connects the input shaft to the ball screw.
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. Holes
extend from the outside surface of the ball screw into the
six grooves in the bore. These holes allow pressurized oil to
enter and exit the two inner elements of the rotary control
valve. The six grooves in the bore of the ball screw are
connected alternately to each side of the piston through
three pairs of the drilled holes. The other three holes admit
pressurized oil directly to three of the six grooves in the
input shaft. The other three grooves in the output shaft carry
oil to the return line connection. The length of the six pairs
of grooves cut into the ball screw and input shaft allows
large pressure changes to be achieved with a small rotational
displacement of the valve elements.
The ball screw assembly is retained in the valve housing by
a valve nut which forms the outermost element of the rotary
control valve. The valve nut contains circular channels and
radial passages which serve to direct hydraulic oil into and
out of the rotary control valve. The ball screw assembly forms
the rotary control and consists of three 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 fits loosely with a similar spline inside the worm screw.
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. The large porting of the
valve design allows neutral position operating pressure to
remain in the 40-65 psi range which results in reduced
hydraulic pump power consumption and lower oil
temperatures.
When steering effort is applied, the input shaft and ball screw
tend to turn in unison however the spring action of the torsion
3
CIRCULAR
GROOVES
BY PASS
VALVE
INPUT
SHAFT
VALVE NUT
OIL IN
ROTARY
VALVE
SUPPLY
OUTPUT
SHAFT
PISTON
SEAL AND
GLIDE RINGS
FIGURE 2
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
OIL OUT
DELIVERY FROM
ROTARY VALVE
SPINDLE ASSEMBLY W/
ROTARY VALVE (BALL
SCREW ASSEMBLY)
OIL PASSAGE
DRAIN PLUG
the appropriate drilled passages in the ball screw to one
side or the other of the piston. Hydraulic pressure acting
upon the piston surface eliminates much of the pistons
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
FIGURE 3
4
BY PASS
VALVE
OIL INLET
CONNECTING POLE
MECHANICAL
MOVEMENT PARTS
MECHANICAL-
HYDRAULIC PARTS
PARTS WITH NO
MOVEMENT
INPUT SHAFT
BEARING
OIL OUTLET
CIRCULAR
GROOVES
LONGITUDINAL
GROOVES
TORSION BAR
BALL SCREW
STRAIGHT AHEAD RIGHT TURNLEFT TURN
FIGURE 4 - SCHEMATIC OF THE ROTARY VALVE OPERATION
RETURN
BY-PASS
VALVE
PUMP
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 3' displacement giving a direct feel to the
steering. Groove displacement is limited by the freeplay 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.
Power assisted movement of the piston nut within its bore
is limited by poppet valves installed in both piston faces.
When the piston approaches its extreme travel in either
direction, the stem of the limiting poppet valve makes contact
at the end of the piston bore. As piston travel continues, the
limiting poppet is unseated and some hydraulic power assist
is removed as pressurized oil is diverted to the return line.
As more and more power assist is removed by the action of
the limiting poppet valves, steering effort increases. The piston
can travel to the extreme ends of its bore, however, the
maximum steering assistance available is reduced to protect
the steering components in the axle.
in operation. Oil displaced from one side of the piston is
essentially transferred to the other side which prevents
reservoir flooding and cavitation in the pressure line.
The pressure relief valve is located in the valve body and
limits internal hydraulic pressure to a preset maximum. The
pressure relief valve can be set to various pressures, however
its setting is 150 p.s.i. lower than the power steering pump
relief valve setting.
POWER STEERING GEAR IDENTIFICATION
A nameplate is installed adjacent to one of the mounting
lugs of the unit which indicates part number, serial number
and build date.
III. TECHNICAL DATA
- Steering ratio ........................................................... 21:1
- Number of turns of the steering wheel ..................... 5.25
- Turning angle on the output shaft .......................90° + 2°
- Output shaft torque obtained with an effective pressure of
1885 p.s.i. (132.5Kg/cm2) .......... 41,947 in.-Ibs (474 m/Kg)
- Hydraulic oil ............................................... Ford part no.
(Ford Esp. M2C1 38-CJ) XT-2-QDX (Dextron II)
- Normal working temperature .................... 248°F(120°C)
- Normal peak temperature ........................ 302°F (150°C)
- Normal flow ......................... 4.2 + 2 G.P.M. (16 + 1 L/m)
- Maximum working pressure 1885 + 60 psi(130+4Kg/cm2)
- Maximum pressure drop in the return ducting .................
............................................................. 60 psi (3 Kg/cm2)
The bypass valve is located in the valve body and permits oil
to flow from one side of the piston to the other when it is
necessary to steer the vehicle without the hydraulic pump
5
IV. PREVENTIVE MAINTENANCE
POWER STEERING OIL
It is important that an approved oil be used to assure proper
operation of the power steering unit. The vehicle
manufacturers recommendations should be adhered to.
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.
2. 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 the old filter
element. Oil the filter support and assemble with a new
filter.
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.
INPUT
SHAFT
VALVE
STOP
BALL BEARING
ROTARY VALVE
GLIDE RING (3)
VALVE NUT
LIMITING
POPPET
RECIRCULATING
BALLS
SPINDLE (BALL
SCREW)
HOUSING
SEAL & GLIDE
RINGS
PISTON
OUTPUT SHAFT
SECTOR GEAR
FIGURE 5
6
TORSION BAR
O-RING (3)
NEEDLE BEARING
BOOT
PITMAN
ARM NUT
OUTPUT
SHAFT
297676 297661
FIGURE 6 - REQUIRED TOOLS
297675 297660297674
V. IMPORTANT! PLEASE READ:
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.
CHANGE INTERVALS
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.
OUTPUT SHAFT SECTOR TEETH ADJUSTMENT
The gear lash 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 disconnected from the vehicle.
The adjustment procedure is described at the end of the
assembly section of this manual.
OUTPUT SHAFT BOOT SEAL
When working on or around the Power Steering system and
components, the following precautions, should be observed:
1. Always block vehicle wheels. Stop engine when working
under a vehicle. Keep hands away from pinch points.
2. Never connect or disconnect a hose or line containing
pressure. Never remove a component or pipe plug unless
you are certain all system pressure has been depleted.
3. Never exceed recommended pressure and always wear
safety glasses.
4. Never attempt to disassemble a component until you
have read and understood recommended procedures.
Use only the proper tools and observe all precautions
pertaining to use of those tools.
5. Use only genuine Bendix replacement parts and
components.
A. Only components, devices and mounting and
attaching hardware specifically designed for use in
hydraulic systems should be used.
B. Replacement hardware, tubing, hose, fittings, etc.
should be of equivalent size, type and strength as
the original equipment.
6. Devices with stripped threads or damaged parts should
be replaced. Repairs requiring machining should not
be attempted.
Inspect the integrity of the output shaft boot seal located
between the pitman arm and housing. This component
prevents contamination from entering the output shaft bearing
and retains grease on the bearing and output shaft to prevent
corrosion. If deterioration or leakage is detected, it should
be replaced.
VI. REMOVING THE POWER STEERING GEAR
1. Mark or identify the inlet and return lines at the valve
body ports.
2. Drain the system following the instructions presented
under preventive maintenance. Remove both inlet and
return lines.
7
3. Disconnect the steering column at the input shaft following
the vehicle manufacturers instructions.
4. Disconnect the pitman arm from the vehicles steering
linkage using the vehicle manufacturers instructions.
CAUTION: If it is necessary to remove the pitman before
the steering gear can be 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.
5. Remove the steering gear from the vehicle.
VII. SPECIAL TOOL REQUIREMENTS
The following special tools are required to disassemble and
assemble the power steering gear.
297661 Spanner Wrench - Used to remove and replace
the valve nut.
297676 Seating Tool - Used to assure seating and
prevent damage to the teflon glide seal rings in the valve
nut during reassembly.
297674 Piloted Seal Tool - Used to seat the seal and
spacer in the body of the power steering gear.
297675 Piloted Seal Tool - Used to seat the seal in
the end cover.
297660 Poppet Wrench - Used to remove and install
limiting valve poppets.
The following special tools are available and are useful
but not required for routine disassembly/assembly of
the power steering gear unless replacement of the
bearing races is required.
297678 Holding Fixture - Used to hold the piston and
the valve assembly during disassembly and assembly.
Note: Part No. 297678 includes the holding fixture and
spanner wrench 297661.
297677 Piloted Bushing Tool - Used to seat the bearing
race in the main housing.
297647 Piloted Bushing Tool - Used to drive bearing
race out of the main housing. Also used to drive split
bearing race into valve body.
VIII. 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.
OUTPUT SHAFT REMOVAL
1. After removing the power steering unit from the vehicle
and cleaning the outside, secure the power steering
unit to the work bench for disassembly. A large vise
with jaw protectors may be used. Clamp across the
mounting bolt bosses. (Do not overtighten.)
2. Using a 17mm wrench, remove the drain plug from the
housing and drain out all oil. (Fig. 8)
3. Loosen and remove the four bolts(1) from the valve body
with a 22mm socket. (See Figures 7 & 9)
297677
FIGURE 6A - NON REQUIRED TOOLS
8
297678
297647
1. Valve Body Bolt
2. Washer
3. Pressure Relief Valve Plug
4. Sealing Washer
5. Adjusting Washer (Shim)
1
8
6
9
7
2
13
14
15
16
3
4
5
10
11
12
17
18
19
28
30
29
28
34
52
53
54
31
29
56
57
32
32
32
31
31
33
29
48
50
51
49
46
47
46
45
22
56
29
55
53
52
6. Pressure Relief Valve Spring
7. Spring Guide
8. Pressure Relief Valve
9. Pressure Relief Valve Seat
10. Sealing Washer
11. By-pass Ball Valve Spring
12. By-pass Ball Valve
13. Input Shaft Dust Seal
14. Snap Ring
15. Input Shaft Seal
16. Valve Body Housing
17. Valve Body O-Ring
18. Valve Body Seal Ring (Nylon)
19. Valve Body O-Ring
20. Pitman Arm Nut
21. Pitman Arm Nut Lock Washer
22. Pitman Arm
23. Output Shaft Boot
24. Boot Retainer
25. Snap Ring
26. Needle Bearing Assy
27. Output Shaft Seal
28. Valve Body & Spindle Ball Bearing
Outer Race (Split)
29. Ball
30. Ball Bearing Cage
31. Valve Nut O-Ring
32. Valve Nut Teflon Glide Ring
33. Valve Nut
34. Spindle Assy. (Valve & Ball Screw Assy.)
35. Output Shaft
36. Output Shaft Adjusting Screw
37. Output Shaft Adjusting Screw
Shim (Washer)
38. Snap Ring
39. Side Cover Output Shaft Seal
40. Side Cover O-Ring
41. Side Cover Assy. (includes Needle Bearing
Assy.)
42. Side Cover Bolt
43. Output Shaft Adjusting Screw Lock Nut
44. Housing Drain Plug
45. Housing
46. Piston Backup Ring
47. Piston O-Ring
48. Piston
49. Recirculating Ball Tube
50. Ball Tube Cover
51. Snap Ring
52. Piston Limiting Body Nut
53. Piston Limiting Body and Valve Seat
54. Piston Limiting Stem (Short)
55. Piston Limiting Stem (Long)
56. Limiting Body Stop Washer
57. Limiting Valve Spring
20
21
FIGURE 7
23
24
25
26
27
35
36
39
2
42
44
37
4
38
40
43
41
9
4. Separate the valve body from the housing by rotating the
output shaft using the pitman arm if it has not been
previously removed. Continue to separate the valve body
from the housing until one of the O-ring seals is visible.
NOTE: It may be necessary to hold or rotate the input
shaft to perform this operation. (See Figure 10)
FIGURE 8
FIGURE 10
5. Remove the pitman arm by unbending the nut lock (21)
and remove the pitman arm fastening nut. Remove the
pitman arm using a large gear puller such as the SnapOn #CG-283 or Ford part number T64P-3590-F.
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 seal. (See Figure 7)
6. Loosen and remove the lock nut(43) from adjusting
screw(36) on the side cover, using a 24mm socket.
Remove the four bolts(42) from the side cover(41) with a
22mm socket. (See Figures 7, 11 & 12)
7. Using a 9mm wrench turn the head of the adjusting
screw(36) clockwise to lift the side cover out of the
housing. (See Figure 13)
FIGURE 9
10
FIGURE 11
41
36
43
FIGURE 12
2
42
8. Install the pitman arm and use it to center the piston
and output shaft sector teeth inside cover opening.
Remove the pitman arm and then remove the output shaft
by tapping gently on the splined end with a nylon mallet.
(See Figures 14 & 15)
FIGURE 14
FIGURE 13
FIGURE 15
11
FIGURE 16
FIGURE 18
PISTON REMOVAL & DISASSEMBLY
9. While preventing rotation of the input shaft, remove the
spindle, valve body and piston from the housing. (See
Figure 16) Remove the two O-rings(19) from the valve
51
49
TOOL 297678
50
29
46
47
body. (See Figure 17) Remove the O-ring(47) and two
back-up rings(46) from the piston groove. (See Figure
18) Remove the snap ring (51) and tube cover(50) and
lift out and remove both halves of the ball return tube(49)
(7 balls inside). (See Figure 19)
FIGURE 17
12
FIGURE 19
45
FIGURE 20
Rotate the input shaft and spindle(34) counterclockwise
to remove the remainder of the 26 internal balls(29) (a
small magnet is a useful tool for this operation.) Separate
the piston from the spindle. (See Figure 21). Holding
FIGURE 21
27
FIGURE 23
25
26
24
23
fixture 297678 pictured is a convenience but not a
necessity to disassemble and assemble the steering
gear.
IMPORTANT: Though being of the same size,
recirculating balls, bearing balls and limiting valve balls
must not be mixed or replaced with each other.
10. Mark or otherwise identify the limiting valve stems (54 &
55) with regard to which end of the piston(48) each is
located. IMPORTANT: These stems must be installed
in the same end of the piston from which they are
removed. (See Figure 7)
11. Using the 6mm hollow hex wrench, tool #297660 (See
Figure 6), installation on the valve stem(54) until the hex
of the wrench engages the hex of the limiting body
nut(52).
12. Using a 6mm socket to turn the hex wrench, remove the
nut(52), body(53), stem(54), ball valve(29), stop
washer(56), and spring(57). The ball valve(29) and
stem(55) may also be removed.
13. Remove the limiting body nut(52) limiting body(53) and
stop washer(56) from the other end of the piston(48).
FIGURE 22
HOUSING DISASSEMBLY
14. Remove the rubber boot(23) and boot retainer(24) from
the main housing(45). (See Figure 22) Take out the
snap ring(25) and extract bearing assy.(26) and
seal(27). (See Figure 23) NOTE: Do not remove the outer
bearing race if in good condition. If it is necessary to
remove the outer bearing race, use tool 297647 and drive
the race into the housing(45) until it is free.
13
41
40
FIGURE 24
39
SIDE COVER DISASSEMBLY
15. Remove O-ring(40) and seal(39). (See Figure 24)
NOTE: Do not attempt to remove the bearing. The side
cover MUST BE replaced if it is determined that the
bearing requires replacement. The side cover is supplied
with the bearing factory installed.
VALVE BODY AND SPINDLE DISASSEMBLY
16. With a drift punch unblock the safety point between
valve nut(33) and valve body(16). Loosen and remove
the valve nut with spanner wrench 297661 and remove
the spindle assembly(34), the ball race(28), the ball
cage(30), and the seventeen bearing balls. (See Figure
25)
14
33
28
34
30
29
17
16
TOOL 297678
FIGURE 25
14
16
15
16
11
12 10
8
9
7
4
3
5
6
FIGURE 26
17. Remove the inner O-ring(17) and the nylon seal ring(18)
from the valve body(16).
NOTE: Do not remove the inner ball race(28) from the valve
body(16) if it is in good condition.
18. Then remove the dust seal(13), snap ring(14) and the
seal(15) from the valve body(16). (See Figures 7 & 26)
PRESSURE RELIEF BYPASS VALVE DISASSEMBLY
19. The power steering valve body(16) contains a pressure
relief and safety valve.
Loosen and remove the plug(3) with a 26mm wrench
and the corresponding seal washer(4).
CAUTION: Located in the plug are the corresponding
maximum pressure adjusting shims(5). (See Figure 27
& 28) Proper reinstallation of the shims is critical to
maintain correct relief pressure.
Remove the spring(6), the guide(7) and the valve(8). With
a wide blade screwdriver loosen and remove the valve
seat(9) and its copper seal washer(10) as well as the
spring(11) and the ball(12) of the bypass valve.
NOTE: Be careful not to damage the I.D. of the valve body or
the valve seat(9) with the screwdriver.
FIGURE 27
15
OUTPUT SHAFT DISASSEMBLY
20. Remove the snap ring(38), the adjusting screw spacer(37)
and the adjusting screw(36) from output shaft. (See
Figure 29)
3
FIGURE 28
8
4
6
5
7
9
12
11
10
SPINDLE DISASSEMBLY
CAUTION: Do not attempt disassembly of the spindle
assembly which contains the rotary valve. Individual
replacement parts are NOT available for this
assembly. It must be treated as a single component.
CLEANING AND INSPECTION
CLEANING
Wash all parts individually in clean solvent and dry thoroughly.
All non-metallic parts should be discarded and replaced with
new.
INSPECTION
Visually inspect all parts carefully paying particular attention
to:
1. Bearings and bearing surfaces including inner and outer
races and balls.
2. Sector gear and piston teeth.
3. Output and input shaft.
4. Exterior of spindle and interior of piston and recirculating
balls.
5. Exterior of piston and 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
35
36
37
38
or boring of these parts as leakage rates will increase.
6. Pitman arm.
7. Housing and mounting lugs.
8. Valve body and porting. Parts found broken, cracked,
distorted or fatigued must be replaced. Cause for the
replacement of any part should be investigated and
corrected to prevent reoccurrence.
FIGURE 29
16
IX. REASSEMBLING THE POWER STEERING
UNIT
To ensure a correct fault-free operation of the power steering
unit, after all parts have been cleaned and faulty ones
replaced, the following assembly procedure should be
followed. The appropriate maintenance kit or kits should be
obtained prior to assembly. Should any of the 17 ball bearing
balls require replacement, replace them all at once; proceed
similarly in case any of the 26 recirculating balls need
replacement. Failure to follow this procedure strictly may
result in a faulty operation of the power steering unit.
16
12 10
11
33
4
9
8
6
7
3
5
28
34
FIGURE 30
VALVE BODY (REFER TO FIGURE 30)
1. Place the valve body(16) in a vise and lightly tighten on
the cast surface. Install the ball(12), spring(11) valve
seat(9) and the copper/seal washer(10). Tighten with
an appropriate screwdriver to a torque of 200 in. lbs.
(See Figure 30)
NOTE: A new copper washer(4) must be used to assure
correct sealing.
Install the relief valve rod(8), the guide(7) and the spring(6).
Place the copper seal washer(4) onto the plug(3) with
the corresponding adjusting shims(5) and tighten with
26 mm. torque wrench. Torque to 66-74 ft. lbs.
2. Install the seal(15), snap ring(14), and dust seal(13) into
valve body(16). (See Figure 31)
3. Using tool number 297647, install the inner ball race(28)
(in the event it was removed), into the bottom of valve
body and install internal O-Ring(17) and the two external
O-Rings(19). (See Figure 32). Install nylon seal(18) in
13
14
15
16
30
29
16
FIGURE 33
the internal threaded portion of the valve body(16). (See
Figure 7)
SPINDLE ASSEMBLY
4. Install the cage(30) on the input shaft end of the
spindle(34). Install the outer ball race(28) and using a
lithium base general purpose grease (Ford Chassis
grease ESA-M1C75-B) to hold them in place insert the
17 new balls(29) comprising the bearing. Insert the
assembly into the valve body. (See Figure 33)
Remove from the valve nut(33), the three teflon glide seal
rings(32) and the three O-Rings(31) and install new ones.
When they are in their respective grooves, insert the
tool 297676 to seat them. (See Figure 34)
NOTE: Make certain the O-rings and glide rings are
in their proper grooves. (Refer to Figure 5) An oil
channel separates each ring.
FIGURE 31
FIGURE 32
16
28
17
19
18
FIGURE 34
33
32
31
297676
17
34
51
297676
33
16
29
49
50
46
47
FIGURE 35
Without removing tool 297676, insert the nut(33) into
the valve body(16), screw and tighten it to a torque of
330 ft. lbs. with a spanner wrench. (See Figure 35)
NOTE: Tool 297676 for the teflon glide rings will come
out as the nut is screwed into the valve body. Lock
the nut in the valve body by staking the edge of the
valve nut into the valve body.
PISTON ASSEMBLY
5. Refer to Figure 37. Install stop washer (56), limiting valve
stem(54), limiting body(53), in the appropriate end of
the piston(48). Apply a small amount of LOCTITE 222
on the threads of the limiting body nut(52) and install
the nut in the piston. Torque the nut to 17 foot pounds
using the 6mm hollow hex wrench (Tool 297660) and a 6
mm socket.
From the opposite end of the piston install one of the two
ball valves (29), the spring (57), ball valve (29), stop washer
(56), limiting valve stem (55), limiting body (53). Apply a
small amount of locktite 222 on the threads of the limiting
body nut (52) and install the nut in the piston. Torque the nut
17 foot pounds using the 6mm hollow hex wrench and a
6mm socket.
18
FIGURE 36
55
52
FIGURE 37
56
29
54
56
48
2953
57
52
53
NOTE: The limiting valve stems (54&55) must be
installed in the same end of the piston as they were
removed. Reference Disassembly, Step 10. When
installing new stems (54&55), the shorter stem must
be installed facing the valve body housing side.
Install the ball screw by inserting it into the piston (48). (See
Figure 36)
Insert the 19 balls (29) one by one in one of the openings for
the recirculating tubes located in the piston (48) while turning
the spindle at the same time. Balls inserted in one opening
should recirculate to the opposite opening as the ball screw
is rotated. Before proceeding, make certain the balls are at
an equal depth in both holes of the piston. (See Figure 38).
This will assure correct installation of the return tube (49).
Install the seven remaining balls(29) into the ball return tube
halves(49) using lithium base general purpose grease (Ford
Chassis grease ESA-M1C75-B) to retain the balls. Place
the tube into piston(48), install the tube cover(50) and its
snap ring(51). Check for smooth operation of the spindle
assembly. (See Figure 39)
NOTE: 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 of it and lodging in the bottom of the
housing(45).
Install the O-Ring(47) and back-up rings(46) on the piston.
(See Figures 36 & 40)
FIGURE 39
FIGURE 38
FIGURE 40
NOTE: Make certain to rotate the glide rings(46) so
that their gaps are 180° apart and not in line with
each other.
HOUSING ASSEMBLY
6. If the outer race of bearing(26) was removed, it must be
reinstalled using tool 297677. Center the narrow bearing
spacer on tool 297677 then install the bearing(26)
complete with its outer race(26) on the tool. Drive the
bearing and race along with the spacer into the housing
from the output shaft side of the housing until the tool
bottoms against the outside of the housing. (See Figures
41A, B & C) Remove the tool and check to be certain
that the outer race and spacer have been driven into the
housing sufficiently deep to allow installation of the snap
ring(25). If the snap ring(25) cannot be installed, remove
the narrow bearing spacer and using tool 297647 drive
the bearing race further into the housing. Reinstall the
narrow bearing spacer and install the snap ring(25),
making certain it is completely seated in its groove. Using
tool 297647 tap the outer race from inside the housing
19
27
26 25
24
23
FIGURE 41
20
until the bearing spacer and outer race are seated against
the snap ring.
Install the seal(27) on tool 297674 so that the seals lip
groove rests against the large diameter of the tool. Next
install the thick bearing spacer on the tool making certain
the flat side of the bearing spacer rests against the seal.
(See Figures 41 E, F & G) Insert the tool with the parts
installed on it through the side cover opening and using
a mallet drive the seal into place.
Install the boot retainer(24) in the housing. Next install
the small diameter of the boot(23) into the retainer,
making certain it is fully seated within the groove formed
by the retainer.
HOUSING & VALVE BODY ASSEMBLY
7. Insert the valve body, spindle and piston assembly into
the housing making certain not to damage the O-ring
seals. Install the 4 bolts(1) and washers(2) that secure
the valve body to the housing and tighten to a torque of
96 ft.lbs. with a 22mm torque wrench.
Turn the input shaft to center the piston teeth(48) in the
side cover opening. This will facilitate the installation of
the output shaft and allow the proper mesh between the
sector and piston teeth. (See Figure 43)
8. Install into the output shaft(35), the adjusting screw(36),
the adjusting screw spacer(37) and the snap ring(38).
Spacer(37) thickness is to be selected so that the axial
play of the adjusting screw is between 0 and .0025 inch
after the snap ring is installed. (See Figure 44)
NOTE: After selecting the proper spacer(37) thickness,
disassemble it, grease the screw head with a lithium
base general purpose grease (Ford chassis grease
ESA-M1C75-B), and reassemble screw, spacer, and
snap ring.
PISTON
OUTPUT
SHAFT
2
16
1
FIGURE 43
ADJUSTING SCREW WASHER
FIGURE 42
FIGURE 44
21
41
40
39
36
35
41
FIGURE 46
Prior to inserting the output shaft into the housing, wrap
a single layer of masking tape around the splines and
threads to protect the housing seal. Lubricate the exterior
of the tape with a lithium base grease (Ford Chassis
grease ESA-M1C75-B) and insert the shaft and side
cover assembly into the housing with a twisting motion.
(See Figure 47)
FIGURE 45
9. Install the side cover seal(39) on tool 297675 so that the
seals lip groove rests against the large diameter of the
tool. Insert the tool with the seal installed into the side
cover and using a mallet drive the seal into place. Install
the o-ring(40) in its groove on the side cover. (See Figure
45)
Pack the output shaft roller bearings in the side cover
and housing with a general purpose lithium base grease
(Ford Chassis grease ESA-M1C75-B). Lubricate the
seals in the side cover and housing using a portion of
the same grease.
10. Install the side cover(41) onto the output shaft(35). Turn
the adjusting screw(36) counterclockwise with a 9mm
socket until finger tight, then back off an eighth of a turn.
(See Figure 46)
NOTE: Be sure output shaft has contacted side cover
prior to backing off an eighth turn.
22
FIGURE 47
FIGURE 48
Install the four washers(2) and the four bolts(42) that
secure the side cover to the housing and torque to 96
ft.lbs. with a 22mm wrench. (See Figure 48)
ADJUSTING THE PISTON - SECTOR TOOTH
BACKLASH
11. The piston and output shaft gear backlash is correct
when a 4 to 18 inch pound increase in torque is noted
as the input shaft is rotated and the piston passes
through the mid point of its total travel in the housing.
The torque increase on the input shaft will occur only
as the piston travels through the mid point of its travel
and should disappear as the piston moves past the mid
point.
To obtain the above adjustment, rotate the input shaft
180° in both directions past the mid point of piston travel.
(The mid point of piston travel is approximately one half
the number of input shaft revolutions possible.)
Each time the direction of input rotation is changed, turn
the output shaft adjustment screw(36) clockwise 1/8 to
1/4 turn. Continue this procedure until the 4-18 inch pound
increase in torque is noted.
NOTE: A 19mm 12 point socket wrench can be used
to rotate the input shaft.
When the adjustment is correct, install lock nut(43) and
apply a torque of 103 ft. lbs with a 24mm torque wrench
while holding the adjusting screw in position with the
9mm socket.
12. After all the described steps have been performed, check
that the power steering unit runs smoothly throughout
its entire motion and that the backlash at the center
position is as prescribed in Step 11 above.
13. Install the pitman arm(22) on the output shaft and secure
it using washer(21) and nut(20). Torque nut to 370-410
ft. lbs.
14. Install the gear on the vehicle and test for flow and
pressure values shown in Section III of Technical Data.
X. PRESSURE, FLOW AND LEAKAGE TESTS
PRELIMINARY
1. Connect Rotunda analyzer kit 14-0230 or equivalent to
the power steering system as shown in Figure 49. Be
sure shutoff valve is fully open.
2. Put front wheels in straight ahead position, transmission
in neutral, parking brake engaged.
3. Start engine and partially close the pressure line shutoff
valve until 800-1000 p.s.i. is read at the pressure gauge.
When temperature of power steering fluid in the
reservoir reaches 120°F, fully open shutoff valve and turn
engine off.
SYSTEM BACK PRESSURE CHECK
1. Insure shut off valve is fully open.
2. Start engine and increase speed to 2200 r.p.m. When
fluid temperature reaches 130°F (55°C), record flow
rate and pressure.
A. If flow is below 3.5 g.p.m. (13.2 L/min.). Check to
see if correct pump is installed. If correct, continue
testing to find problem.
B. If pressure exceeds 80 p.s.i. (552 kPa), check lines
for kinks or obstructions. If none are found and
pressure remains high, continue testing to find
problem.
MINIMUM PUMP FLOW
1. Decrease engine speed to 600 rpm.
2. Slowly close shutoff valve to increase pressure to 1200
p.s.i.
3. Record flow rate at 130°F (55°C).
4. If flow rate is below 2.2 g.p.m. (8.3 L/min), then verify
correct pump is installed. Pump may require repair or
replacement especially if flow at 2200 r.p.m. was also
below specification.
RELIEF PRESSURE TEST - POWER STEERING
PUMP
1. With the engine running at 600 r.p.m. close the shutoff
valve and read the pressure gauge and note the flow
rate is 0. OPEN THE SHUTOFF VALVE QUICKLY after
reading the gauge pressure and note the flow rate returns
to normal. If the pressure reading is below 1800 p.s.i. or
above 2250 p.s.i., repair or replacement of the relief valve
is necessary.
CAUTION: The shutoff valve must not remain closed
longer than FIVE SECONDS or damage to the pump
may result.
23
2. Allow the power steering pump fluid to cool to 130°F
before testing is resumed.
3. With the engine at full governed R.P.M. close the shutoff
valve and note that the flow reads 0. QUICKLY OPEN
THE SHUTOFF VALVE, and note that the flow rate
immediately returns to normal. Repeat this test once
but do not allow fluid temperature to exceed 200°F.
If the flow rate does not immediately return to normal,
pump repair or replacement is indicated.
RELIEF PRESSURE TEST & INTERNAL
LEAKAGE TEST - POWER STEERING GEAR
1. To test the pressure relief valve and internal leakage of
the power steering gear, it is necessary to prevent
operation of the gears poppet valves contained in the
piston. This can be accomplished by placing a steel
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 stops contact the
spacer block. (See Figure 50) Apply sufficient torque
to the steering wheel to assure 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 above
THERMOMETER
OIL
RESERVOIR
POWER STEERING
GEAR
AXLE STOP
FIGURE 50
1945 p.s.i. or below 1825 p.s.i. relief valve adjustment or
repair is 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 of the
gear has been reached. It may damage the unit or
cause the temperature of the oil to raise beyond 200°.
4. In order to test the steering gear for internal leakage it is
necessary to TEMPORARILY adjust the setting of the
power steering gear pressure relief valve above that of
the power steering pump relief valve. To accomplish
this install the appendix pressure relief valve test plug
assembly 106773.
To install the plug assembly: (See Figure 7)
A. With the engine stopped, remove the pressure relief
valve plug (3) sealing washer (4) adjusting shims (5)
and spring(6).
B. Install the sealing washer on the test plug assembly
(106773) then install the test plug assembly in the
power steering gear valve body. Torque the test plug
assembly to 66 - 73 pound feet.
5. Run the engine at idle. Turn the steering wheel until the
axle stop contacts the spacer block. (See Figure 50)
Apply a sufficient torque to the steering wheel to assure
the power steering gear control valve is completely open
in the direction of the turn. Observe the following.
POWER STEERING PUMP
FIGURE 49
24
FLOW
METER
GAUGE
SHUTOFF
VALVE
PRESSURE RELIEF VALVE TEST PLUG ASSEMBLY
PART NUMBER 106773
A. Gauge pressure should read the same as the power
steering pump relief pressure. (See Step 1 under
Relief Pressure Test - Power Steering Pump)
B. With system pressure at pump relief, read the flow
meter. If a flow greater than 3.5 quarts per minute is
noted, internal leakage is excessive and the steering
gear requires repair.
6. Repeat Test 5 turning the steering wheel in the opposite
direction.
IMPORTANT: Remove the pressure relief valve test
plug assembly which was in Step 4, before placing
the vehicle in service.
XI. TROUBLESHOOTING
PRELIMINARY CHECKS
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 still 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 still 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.
25
TROUBLESHOOTING CHART
SYMPTOM CAUSE REMEDY
1. Power steering does A. Low oil level. A. Check oil level.
not operate.
B. Air in system. B. Check that there are
no leaks, bleed and
top up with oil.
C. The pressure pump does C. Check pump performance to
not supply an adequate specification.
flow or pressure.
D. Obstruction in the oil D. Remove lines and clean.
reservoir outlet or
inlet.
E. Communication between E. Change piston seal rings.
sides of power steering
piston.
F. Mechanical faults in F. Overhaul and test in
vehicle steering members, accordance with vehicle
not belonging to power service manual.
steering gear.
G. Low pressure in front G. Inflate tires to correct
tires. pressure.
H. Relief valve opens at H. Disassemble and repair.
low pressure.
I. Faulty operation of the I. Replace ball screw assembly.
rotary valve.
2. Power steering stiff A. No pressure being applied A. Check and if necessary
in one direction and to top or bottom side of replace seal rings (31, 32)
normal in the other. power steering piston.
B. Faulty operation of the B. Replace ball screw
rotary valve. assembly.
C. Mechanical fault in vehicle C. Overhaul and check in
steering members not accordance with vehicle
belonging to power service manual.
steering units.
D. Excess leakage through D. Disassemble and repair.
piston limiting valve in one
direction.
3. Power steering tends A. Rotary valve incorrectly A. Replace ball screw
to turn by itself set. assembly.
when engine is running.
4. Excessive free play A. Power steering housing A. Retighten mounting bolts.
in steering wheel. or housing support loose.
B. Excessive play between B. Adjust gear lash. If all
output shaft sector teeth adjustment has been used,
and piston. replace piston and output
shaft.
C. Loose or worn ball studs in C. Mechanical faults in vehicle
steering linkage. Loose or steering members. See
worn intermediate steering vehicle manual.
shafts.
26
SYMPTOM CAUSE REMEDY
5. Power steering A. Faulty operation of A. Check pump to performance
operates normally pressure pump. specification. Overhaul
but is intermittently by authorized workshop
hard. if required.
B. Low oil level. B. Check oil level.
C. Dirty oil. C. Change oil.
6. Oil leaks. A. Faulty or incorrectly A. Clean and dry the outside
installed seal rings. of the power steering
body and take the vehicle
out on test to locate the
leak.
B. Hose or hose connections. B. Tighten or replace.
7. Power steering stiff A. Faulty operation of A. Check pump to performance
when turning steering hydraulic pump. specifications. Overhaul
wheel quickly. by authorized workshop.
B. Restricted hose. B. Replace incorrect or
unserviceable hoses.
C. Incorrect hose size. C. Replace incorrect or
unserviceable hoses.
8. Power steering does A. Front axle assembly. A. Lubricate front axle
not return correctly. assembly. Check for
damaged or worn parts.
B. Lower steering gear parts B. Replace the ball screw
deformed as a result of assembly.
accident or breakdown in
the rotary valve unit.
C. Low tire pressure. C. Inflate tires to correct
pressure.
D. Bind in intermediate shafts. D. Determine cause and correct.
9. Power steering A. Unsuitable oil. A. Drain oil and fill up with
operates but with recommended grade.
noise turbulence
or vibration.
B. Dirt inside the B. Overhaul by authorized
pressure pump. workshop.
C. Oil reservoir filter C. Replace filter.
blocked.
D. Piping contacting part D. Space pipe from bodywork.
of the bodywork, causing If not possible, insulate
vibrations (particularly with a rubber spacer.
the pressure feed pipe).
E. Reservoir oil level low. E. Fill up to level and
check installation.
BW1450 © 2002 Bendix Commercial Vehicle Systems LLC All rights reserved. 3/2002 Printed in U.S.A.
27
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