1988 JEEP CHEROKEE Service Repair Manual

NOTE: If reading does not fall within this range, adjuster plug
may have turned while lock nut was being tightened. Steering
gear may be incorrectly assembled or worm shaft thrust
bearings and races may be defective. Repair as required and
readjust preload.
Fig. 2: Measuring Thrust Bearing Preload
OVER-CENTER PRELOAD TORQUE ADJUSTMENT
1) Loosen adjuster screw lock nut. Back off adjuster screw
until stopped, then turn in 1 full turn. Rotate input shaft from stop
to stop counting number of turns. Turn shaft half way back to center
position.
2) Attach an INCH lb. torque wrench to input shaft. Turn

shaft from side to side through specified arc on each side of center.
See OVER-CENTER PRELOAD chart. Note torque reading going over center.
Adjust thrust bearing preload before over-center preload. See Fig. 3.
OVER-CENTER PRELOAD SPECIFICATIONS - INCH LBS. (N.m)









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Application Arc Over-Center (1) Total
New Gears .......... 45
 ........ 4-8 (.4-.9) ......... 14 (1.5)
Used Gears ( 2) ..... 45 ........ 4-5 (.5-.6) ......... 14 (1.5)
( 1) - Total preload is sum of thrust bearing and over-center preload.
( 2) - In service for more than 400 miles (640 km.).









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Fig. 3: Adjusting Over-Center Preload
REMOVAL & INSTALLATION
POWER STEERING PUMP
Removal & Installation
1) Loosen and remove pump drive belt. Disconnect pressure and
return hoses from pump. Cap ends to prevent loss of fluid or
contamination.
2) Remove bracket-to-engine bolts. Remove pump and mounting
bracket as an assembly. To install, reverse removal procedure. Fill
and bleed system.

Fig. 4: Power Steering Pump (Cherokee & Commanche)

Fig. 5: Front Bracket Boltsp (Cherokee & Commanche)
STEERING GEAR
Removal
1) Remove collapsible steering column. Raise and support
vehicle. Place drain pan under steering gear assembly. Center steering
gear. Disconnect hydraulic hoses from gear and cap ends. Disconnect
steering linkage from pitman arm. Remove pitman arm from gear.
2) Remove flexible coupling clamp bolt and bolts retaining
steering gear to frame. Disconnect gear from flexible coupling and
remove gear from vehicle. On Jeep CJ7 and Scrambler models, remove
steering gear and mounting bracket as an assembly.
Installation
To install, reverse removal procedure. Fill pump reservoir.
Bleed air from system. See POWER STEERING GENERAL SERVICING article.

OVERHAUL
SUBMERGED VANE POWER STEERING PUMP
Disassembly
1) Drain pump reservoir. Clean exterior of unit. Measure
distance shaft protrudes from pulley, and record for assembly
reference. Using pulley remover, remove pulley from shaft. Clamp pump
in vise; DO NOT overtighten vise. Remove pressure line union,
reservoir mounting stud and reservoir. See Fig. 6. Remove and discard
pressure line union "O" rings.
Fig. 6: Exploded View of Pump Assembly (Grand Wagoneer & Wrangler)
Courtesy of Chrysler Motors
2) Using punch and screwdriver, remove end plate retaining
ring. Remove end plate and pressure plate spring. Remove "O" ring,
flow control valve and spring. Note direction of pump ring
installation for reassembly reference.
3) Using soft-faced hammer, tap end of drive shaft to loosen
pressure plate. Remove pressure plate, pump ring, vanes, retaining
ring, rotor and thrust plate assembly from body. Remove drive shaft.
Using a screwdriver, pry drive shaft oil seal from housing. Remove
dowel pins and seals.
Cleaning & Inspection
1) Clean all pump components in solvent, and blow dry.
Inspect flow control valve assembly for wear, scoring, burrs and other
damage. Inspect seal bore for burrs, nicks and score marks.
2) Inspect machined surfaces of body for scratches and burrs.
Check "O" ring mating surfaces. Inspect drive shaft for excessive
wear.
3) Inspect pump ring for roughness. Check thrust plate and
pressure plate for scoring and wear. Ensure vanes slide freely but fit
snugly into slots. If vanes are loose in slots, replace rotor and/or
vanes.
Reassembly
1) Before installation, coat all "O" rings, rotor, pressure

plate and end plate with petroleum jelly. Install new drive shaft seal
in housing. Install "O" ring in third groove of housing. Install dowel
pins in thrust plate. Install drive shaft through thrust plate and
rotor. Install NEW retaining ring. Ensure rotor slides freely on drive
shaft splines.
2) Install drive shaft in pump housing. Ensure thrust plate
engages with dowel pins. Install pump ring on dowel pins with rotation
arrow facing upward. Install vanes with rounded edges toward pump
ring.
3) Lubricate outer chamfered edge of pressure plate with
petroleum jelly. Install pressure plate with spring groove facing
upward. To seat pressure plate, place large socket on pressure plate
and press downward approximately 1/16".
4) Install end plate "O" ring in second groove of housing.
Install pressure plate spring and end plate in housing. Press end
plate downward, and install retaining ring. Install "O" ring, flow
control valve and spring.
5) Install mounting stud and pressure line union "O" rings in
rear of pump housing. Lubricate inner edge of reservoir with petroleum
jelly, and install. Install mounting stud. Tighten stud to
specification. Install pressure line union, and tighten to
specification. See appropriate table under TORQUE SPECIFICATIONS.
6) Using Pump Pulley Installer (J-25033-B), install pulley o\
n
pump shaft. Ensure shaft protrudes distance measured in disassembly
procedure.
7) When replacing plastic pulley with metal pulley, install
pulley flush with end of shaft. Install pump on engine, and compare
alignment with adjacent pulleys. If necessary, correct alignment by
using pump pulley installer to adjust shaft protrusion.
NON-SUBMERGED VANE POWER STEERING PUMP
Disassembly
1) Remove return tube. Clean exterior of unit. Measure
distance shaft protrudes through pulley, and record for reassembly
reference. Using pulley remover, remove pulley from shaft. Remove
fitting, "O" ring, flow control valve and spring. See Fig. 7.
2) Remove snap ring, drive shaft and bearing. Note direction
of snap ring installation for reassembly reference. Support drive
shaft bearing on inner race, and press drive shaft from bearing. Using
screwdriver, remove drive shaft seal from housing.
3) Insert punch into access hole to disengage and remove
retaining ring. Using a brass drift, tap on thrust plate, and remove.
Remove "O" ring, pump ring, rotor and vanes. Remove dowel pins,
pressure plate, "O" ring and pressure plate spring. Remove "O" ring,
dowel pin and sleeve.
Fig. 7: Exploded View of Cherokee & Comanche Pump Assembly
Courtesy of Chrysler Motors

Cleaning & Inspection
1) Clean all pump components in solvent, and blow dry.
Inspect flow control valve assembly for wear, scoring, burrs and other
damage. Inspect seal bore for burrs, nicks and score marks.
2) Inspect machined surfaces of body for scratches and burrs.
Check "O" ring mating surfaces. Inspect drive shaft and sleeve for
wear.
3) Inspect pump ring for roughness. Check thrust plate and
pressure plate for scoring and wear. Ensure vanes slide freely but fit
snugly into slots. If vanes are loose in slots, replace rotor and/or
vanes.
Reassembly
1) Lubricate all "O" rings, seals, pump ring, rotor and vanes
with petroleum jelly. Install sleeve. Ensure sleeve is fully seated.
2) Install "O" ring in sleeve seat. Install small dowel pin
in pump housing. Install pressure plate spring and "O" ring. Install
pressure plate with dowel pin hole aligned with dowel pin holes.
Install dowel pins.
3) Install pump ring with identification marks located
adjacent to one dowel pin. Install rotor with counterbore toward drive
shaft end of housing.
4) Install vanes with rounded edges toward pump ring. Install
thrust plate "O" ring. Install thrust plate with indentations aligned
with bolt holes of housing. Install retaining ring.
CAUTION: Pump ring must be installed with identification marks
located adjacent to dowel pins. Thrust plate must be
installed so indentations in thrust plate align with bolt
holes of housing and thrust plate engages with pump ring
dowel pins.
5) Using a socket, install drive shaft seal in housing until
seal bottoms. Support drive shaft bearing on inner race, and press
drive shaft into bearing. Install drive shaft and bearing in pump
housing.
6) Rotate drive shaft during installation to align with rotor
serrations. Ensure bearing is fully seated in pump housing. Snap ring
should be installed with large lug area (near snap ring pliers hole)
positioned right of small lug (near snap ring pliers hole), ensuring
beveled area of snap ring is properly positioned.
7) Install spring, flow control valve and "O" rings. Install
return tube with new "O" ring. Install pulley.
STEERING GEAR
Disassembly
1) Cap all openings in gear. Clean gear exterior thoroughly.
Mount gear in vise so that pitman shaft points downward. Rotate
housing end plug retainer ring until one end of plug is over the hole
in the housing.
2) Force end of ring from groove in housing and remove.
Rotate input shaft counterclockwise to force housing end plug out of
housing. Rotate input shaft clockwise 1/2 turn to draw rack/piston
inward. Remove piston end plug.
CAUTION: DO NOT rotate shaft more than is necessary to remove plug as
ball bearings will fall out of worm and rack piston assembly.
3) Remove lock nut from sector shaft adjuster. Remove sector
shaft cover. Remove and discard "O" ring from cover. Turn input shaft
until sector shaft teeth are centered in housing.

4) Tap end of sector shaft with a soft-faced hammer to free
shaft from housing, then remove sector shaft. Remove adjuster plug
lock nut. Remove adjuster plug with a spanner wrench.
5) Insert a rack/piston arbor into end of rack/piston until
arbor just contacts worm shaft. Turn stub shaft counterclockwise to
force rack/piston onto arbor. Remove rack/piston and arbor as an
assembly.
6) Take care to keep arbor fully inserted so ball bearings
will not fall out. Remove input shaft and control valve assembly from
housing. Remove worm, wormshaft lower thrust bearing, and races from
housing.
Reassembly
1) Lubricate all parts with clean power steering fluid before
reassembly. Install the lower thrust bearing and races onto the worm.
Cupped side of thrust washers must face toward stub shaft. See Fig. 8.
Fig. 8: Reassembly of Valve Body & Worm Shaft Assembly
NOTE: If conical thrust races are used, ensure tapered surfaces
are parallel to each other and that cupped sides face toward
stub shaft.