SUSPENSION - FRONT (4WD)

1991 Mitsubishi Montero

1990-92 SUSPENSION
Front - 4WD Trucks

Chrysler Motors; Ram-50

Mitsubishi; Montero, Pickup

DESCRIPTION
The independent front suspension uses upper and lower control
arm and torsion bar construction. The components used with this system
are upper control arm, lower control arm, torsion bar, shock absorber,
stabilizer bar, steering knuckle, drive shaft and front differential.
See Fig. 1.

Fig. 1: Replacing Upper Ball Joint (Montero)

Courtesy of Mitsubishi Motor Sales of America.

BALL JOINT CHECKING

 LOWER BALL JOINT
Place ball joint in soft-jawed vise. Install dial indicator,
with stem resting on end of ball joint stud. Measure ball joint stud
end play. Replace ball joint if end play exceeds .02" (.5 mm).

UPPER BALL JOINT

1) With ball joint disconnected from steering knuckle, place
nut on ball joint stud. Using INCH lb. torque wrench, measure starting
torque required to rotate ball joint stud.
2) Starting torque must be 7-30 INCH lbs. (.8-3.4 N.m). If
starting torque is not within specification, replace ball joint
(Montero) or upper arm (Ram-50 and Pickup). For ball joint replacement
on Montero, see UPPER BALL JOINT under REMOVAL & INSTALLATION.

WHEEL BEARINGS ADJUST

PRELOAD
1) Remove locking hub assembly. See LOCKING HUB under REMOVAL
& INSTALLATION. Remove lock washer-to-lock nut bolts and lock washer.
Remove brake caliper to ensure brake pads are not contacting rotor.
2) Using Socket (MB990954-01) and torque wrench, rotate front
hub and tighten lock nut to 95-145 ft. lbs. (129-197 N.m) to seat
bearings. Loosen nut.
3) Retighten nut to 18 ft. lbs. (24 N.m) and loosen 30-40
degrees. After setting preload, check hub turning resistance and axial
play.

HUB TURNING RESISTANCE & AXIAL PLAY

1) Using INCH lb. torque wrench or spring scale attached to
wheel stud, measure hub turning resistance. Turning resistance should
be 1-4 lbs. (.45-1.8 kg) if measured with spring scale or 2.6-11.3
INCH lbs. (.3-1.3 N.m) if measured with torque wrench.
2) Using dial indicator, check front hub axial play. Axial
play should be .002" (.05 mm) or less. Adjust wheel bearing so turning
resistance and axial play are within specification. If turning
resistance and axial play cannot be adjusted to specifications, check
wheel bearing condition and installation. Install lock washer.
3) If lock washer and lock nut holes are not aligned, align
holes by loosening lock nut a maximum of 40 degrees. Install lock
washer bolts to lock nut. Tighten lock washer bolts. Install locking
hub.

LOWER BALL JOINT R & I

REMOVAL
1) Raise and support vehicle. Remove wheel assembly. Support
lower control arm enough to release torsion bar tension. Loosen but DO
NOT remove lower ball joint-to-steering knuckle nut.
2) Using ball joint separator, separate ball joint from
steering knuckle. Remove ball joint nut from steering knuckle. Remove
ball joint-to-lower control arm bolts. Remove ball joint.

INSTALLATION
 Lubricate ball joint with SAE J310 NLGI No. 2 grease. Apply
semi-drying sealant to ball joint grooves. Reverse removal procedure
to complete installation. Tighten bolts to specification. See TORQUE
SPECIFICATIONS table at end of article.

NOTE: On Ram-50 and Pickup, replace upper control arm if ball

joint is defective.

UPPER BALL JOINT R & I (MONTERO)

REMOVAL
Remove snap ring and dust cover together from ball joint. See
Fig. 1. Use Ball Joint Remover/Installer (MB990799-01 and MB990800-01)
and Clamp (MB990840-01) to press ball joint from control arm. Tighten
clamp to remove ball joint.

INSTALLATION
1) Before installing, align reference mark on ball joint with
center of control arm. Using bushing remover/installers, install ball
joint in control arm. See Fig. 1.
2) Install snap ring on ball joint. Lubricate ball joint with
SAE J310 NLGI No. 2 grease. Apply semi-drying sealant to ball joint
grooves. Install new dust cover and ring.

AUTOMATIC TYPE LOCKING HUB R & I

REMOVAL
1) Place hub must in the FREE position by placing transfer
case lever in 2H position and moving vehicle in Reverse approximately
4-6 feet.
2) Remove cover from locking hub. If necessary, wrap shop
towel around cover and use an oil filter wrench to loosen cover. Raise
and support vehicle. Remove wheel assembly.
3) Using snap ring pliers, remove snap ring and shim from end
of drive axle. See Fig. 2. Using hexagonal wrench, remove locking hub
retaining bolts. Remove locking hub assembly.

Fig. 2: Exploded View of Automatic Locking Hub

Courtesy of Chrysler Motors.

INSTALLATION
 1) Using Socket (MB990954) and torque wrench, rotate front
hub and tighten lock nut to 95-145 ft. lbs. (129-197 N.m) to seat
bearings. Loosen nut. Retighten nut to 18 ft. lbs. (24 N.m) and loosen
30-40 degrees.
2) Using spring scale attached to wheel stud, measure and
record turning resistance required to rotate hub/rotor assembly before
installing locking hub.
3) Apply semi-drying sealant on locking hub assembly-to-
hub/rotor contact areas. DO NOT apply sealant on outer areas of
hub/rotor assembly, toward brake contact areas.
4) Align locking hub assembly key area with steering knuckle
keyway area. Loosely install locking hub assembly on hub/rotor
assembly. Ensure locking hub assembly fully contacts hub/rotor
assembly.
5) Install locking hub retaining bolts. Tighten to
specification. See TORQUE SPECIFICATIONS table at end of article.
Using spring scale attached to wheel stud, measure turning resistance
required to rotate hub/rotor assembly.
6) Subtract turning resistance measured in step 2) (before
installing locking hub) from turning resistance measured in step 5)
(after installing locking hub). If difference exceeds 3.1 lbs. (14 N),
check for incorrect installation of locking hub assembly or
components.
7) Install shim and snap ring on drive axle. Rotate drive
axle until maximum end play is obtained. Using dial indicator, check
drive axle end play.
8) Drive axle end play should be .008-.020" (.20-.51 mm). If
end play is not within specification, adjust drive axle end play by
changing axle shaft shim. Install new "O" ring and cover. Tighten
cover to specification. See TORQUE SPECIFICATIONS table at end of
article.

LOWER CONTROL ARM R & I

REMOVAL
1) Raise and support vehicle. Remove wheel assembly. Remove
front skid plate and undercover (if equipped). Remove torsion bar. See
TORSION BAR under REMOVAL & INSTALLATION. Remove stabilizer bar bolt
from control arm.
2) Remove shock absorber-to-control arm bolts. Loosen but DO
NOT remove lower ball joint-to-steering knuckle nut. Using ball joint
fork, separate lower ball joint from steering knuckle.
3) Remove ball joint stud nut from steering knuckle. Remove
control arm shaft. See Fig. 1. Remove torque arm. Remove lower control
arm pivot bolt. Remove lower control arm.

INSPECTION
1) Inspect control arm for cracks or deformation. Check ball
joints. See BALL JOINT CHECKING under ADJUSTMENTS & INSPECTION.
2) Inspect ball joint dust covers for damage. Replace dust
covers if damaged. Inspect control arm bushing and frame bracket
bushing for damage. Replace if necessary.
3) If frame bracket bushing needs replacing, install Bushing
Remover/Installer (MB990958-01) in bushing. See Fig. 3. Tighten
bushing remover/installer bolt until bushing is removed. Reverse
bushing remover/installer to install bushing.

NOTE: Differential carrier may require relocation to replace left

bracket bushing.
 4) If control arm bushing needs replacing, use press and
Bushing Remover/Installer (MB990883-01). Press bushing from control
arm. See Fig. 4.
5) Coat bushing and control arm with soapy solution. Using
press and bushing remover/installer, press bushing into control arm.
Position bushing so there is equal distance from bushing-to-control
arm at both ends.
6) Reverse bushing remover/installer to install bushing.
Position bushing so there is equal distance from bushing-to-control
arm at both ends.

CAUTION: Tighten lower control arm shaft and pivot bolt to

specification with vehicle at normal operating height.

INSTALLATION
1) To install, reverse removal procedure. Ensure White mark,
located on lower mounting end of shock absorber, faces toward outside
of vehicle. Tighten lower control arm shaft and pivot bolt to
specification with vehicle at normal operating height.
2) Tighten bolts to specification. See TORQUE SPECIFICATIONS
table at end of article. Install new nut on stabilizer bar-to-control
arm bolt. Tighten stabilizer bar-to-control arm bolt until distance
from threaded end of bolt to nut is .24-.31" (6.0-7.8 mm).

Fig. 3: Replacing Bracket Bushing

Courtesy of Mitsubishi Motor Sales of America.
Fig. 4: Replacing Lower Control Arm Bushing
Courtesy of Mitsubishi Motor Sales of America.

STABILIZER BAR R & I

 REMOVAL
Remove skid plate (if equipped). Remove stabilizer bar bolt
from lower control arm. Remove stabilizer bar clamp-to-hanger bolts.
Remove stabilizer bar and bushings. Remove stabilizer bar-to-frame
hangers (if necessary).

INSTALLATION
Inspect bushings for wear. Check stabilizer bar for
deformation. To install, reverse removal procedure. Install stabilizer
bar-to-frame hangers and stabilizer bar-to-control arm bolt using new
nuts. Tighten hanger-to-frame nut and stabilizer bar-to-control arm
nut until distance from threaded end of bolt to nut is .24-.32" (6.1-
8.1 mm).

STEERING KNUCKLE R & I

REMOVAL
1) Raise and support vehicle. Remove wheel assembly. Remove
brake caliper. Remove hub/rotor assembly. See WHEEL BEARINGS under
REMOVAL & INSTALLATION. Remove dust cover from steering knuckle.
2) Disconnect tie rod end from steering knuckle. Loosen
torsion bar anchor arm assembly adjusting nut. Loosen ball joint-to-
steering knuckle nuts. Using ball joint separator, separate ball
joints from steering knuckle.
3) Detach upper and lower ball joints from steering knuckle.
Remove steering knuckle from drive axle. Remove oil seal and spacer
from steering knuckle.

INSPECTION
Inspect steering knuckle for cracks. Inspect spindle and
steering knuckle needle bearing for wear or damage.

INSTALLATION
1) If needle bearing requires replacement, drive bearing from
steering knuckle. Use Bearing Driver (MB990956-01) and Handle
(MB9909938-01) to install needle bearing.

NOTE: DO NOT reuse steering knuckle bearing if removed.

2) Using bearing installer and handle, install new needle

bearing until bearing is even with steering knuckle end face. Apply
SAE J310 NLGI No. 2 grease to bearing roller surface and spacer-to-
steering knuckle contact areas. Install spacer with chamfered side
toward inside of vehicle.
3) Using Seal Installer (MB990985-01) and Handle (MB990938-
01), install seal in steering knuckle until seal is even with steering
knuckle end face. Apply grease to seal lip area and inside of seal. To
complete installation, reverse removal procedure. Tighten bolts to
specification. See TORQUE SPECIFICATIONS table at end of article.

TORSION BAR R & I

CAUTION: Mark torsion bar and anchor arm location for reassembly
reference before removing.
 REMOVAL
1) Raise and support vehicle. Support lower control arm with
jack stand. Loosen anchor arm adjusting bolt lock nut. On Montero,
remove heat protector from frame (right side only). Loosen anchor bolt
to release torsion bar tension.
2) Place reference marks on front of torsion bar, torque arm
and torsion bar-to-torque arm for reassembly reference. Remove anchor
arm. See Fig. 1.
3) Remove dust cover from end of torsion bar. On Montero,
remove heat cover (left side only) located between dust cover and
torsion bar. On all models, remove torsion bar.

INSPECTION
Inspect all splined areas for damage. Inspect dust covers for
cracks or damage. Check for bent anchor bolts. Replace components as
necessary.

INSTALLATION
1) Apply grease to splined areas of torsion bar, anchor arm,
torque arm splines, anchor bolt threads and inside of dust cover.
Check for left and right identification marks on torsion bars’ ends.
Ensure torsion bars are installed in correct location.
2) Install torsion bar in torque arm, with identification
mark toward front of vehicle. Align mark on torque arm with mating
mark on torsion bar. When installing a new torsion bar, align the
White paint spline with index mark on front torque arm.
3) Install anchor arm on torsion bar so initial length of
adjusting bolt from flat surface of upper and lower half moon washers
is within specification. See Fig. 5.
4) See ANCHOR BOLT INITIAL SPECIFICATIONS table. Ensure upper
control arm rebound stopper is contacting crossmember before adjusting
initial setting.

NOTE: Ensure upper control arm rebound stopper is contacting

crossmember when adjusting initial settings.

Fig. 5: Adjusting Anchor Arm Bolt

Courtesy of Mitsubishi Motor Sales of America.

ANCHOR BOLT INITIAL SPECIFICATIONS TABLE

Application In. (mm)

Montero
Left Side .................. 5.3-5.6 (135-142)
Right Side ................. 4.9-5.2 (124-132)
Ram-50 & Pickup
Left Side .................. 5.5-5.8 (140-147)
Right Side ................. 5.3-5.6 (135-142)


















































5) After initial torsion bar setting, tighten anchor bolt
adjusting nut to obtain correct final bolt protrusion.
6) On Montero, final bolt protrusion depends upon curb weight
of vehicle. Adjust anchor bolt adjusting nut to obtain final anchor
bolt protrusion. See appropriate FINAL ANCHOR BOLT PROTRUSION table.

FINAL ANCHOR BOLT PROTRUSION TABLE (MONTERO)

Curb Weight Right Bolt Left Bolt
Lbs. (kg) In. (mm) In. (mm)

2910 (1320) ........... 2.6 (65) .............. 2.2 (55)

3000 (1360) ........... 2.7 (68) .............. 2.2 (55)
3080 (1400) ........... 2.8 (71) .............. 2.3 (57)
3170 (1440) ........... 2.8 (71) .............. 2.4 (59)
3260 (1480) ........... 2.9 (72) .............. 2.5 (62)
3350 (1520) ........... 3.0 (76) .............. 2.5 (62)
3440 (1560) ........... 3.0 (76) .............. 2.6 (65)
3530 (1600) ........... 3.1 (78) .............. 2.6 (65)
3620 (1640) ........... 3.2 (80) .............. 2.7 (68)
3700 (1680) ........... 3.2 (80) .............. 2.8 (71)
3790 (1720) ........... 3.3 (84) .............. 2.9 (72)
3880 (1760) ........... 3.4 (86) .............. 2.9 (72)
3970 (1800) ........... 3.4 (86) .............. 3.0 (76)
4060 (1840) ........... 3.5 (88) .............. 3.1 (78)




























































FINAL ANCHOR BOLT PROTRUSION (RAM-50 & PICKUP)




























































Right Bolt Left Bolt
Application In. (mm) In. (mm)

Ram-50 & Pickup ..... 3.39 (86.1) ......... 3.94 (100.1)

FINAL ANCHOR BOLT PROTRUSION (1992 MONTERO)




























































Right Bolt Left Bolt
Application In. (mm) In. (mm)

Montero ............. 3.15 (80.0) .......... 3.15 (80.0)

7) To complete installation, reverse removal procedure.
Tighten bolts to specification. See TORQUE SPECIFICATIONS table at end
of article. Place unladed vehicle in normal operating height. Measure
clearance between lower control arm bump stop and bump stop bracket on
frame.
8) On Montero, clearance should be 2.8" (71 mm). On Pickup,
clearance should be 3.1" (78 mm). If clearance measurements are NOT as
specified, adjust anchor bolt adjusting nut to obtain correct
clearance.
 UPPER CONTROL ARM R & I

REMOVAL
1) Remove shock absorber. Support lower control arm with jack
stand. Remove wheel assembly. Loosen anchor bolt lock nut. See Fig. 1.
2) Mark anchor bolt for reassembly reference. Loosen anchor
bolt to release torsion bar tension. Disconnect and plug brake hose at
frame mount bracket. Remove cotter pin from ball joint stud. Loosen
but DO NOT remove ball joint stud knuckle nut.
3) Using ball joint fork, loosen ball joint from steering
knuckle. Remove ball joint stud nut. Remove rebound stopper and brake
hose support from control arm. Remove upper control arm mounting
bolts. Note direction of bolt installation and location of camber
adjustment shims. Remove control arm.
4) If clearance is inadequate for control arm removal, move
control arm toward rear of vehicle and pull out front part of arm.
Rotate control arm pivot shaft and remove arm. If arm still cannot be
removed, loosen 10 front body mounting nuts. Raise body and remove
arm.

NOTE: On Montero, rotating control arm shaft will alter caster

setting.

INSPECTION
1) Inspect control arm for cracks or deformation. On Montero,
mount control arm in soft-jawed vise using control arm shaft. Attach
spring scale to upper end of control arm, near ball joint.
2) Using spring scale, measure starting torque required to
rotate control arm on the shaft. Replace control arm if starting
torque exceeds 1.4 lbs. (6.5 N).
3) On all models, check ball joints. See BALL JOINT CHECKING
under ADJUSTMENTS & INSPECTION. Inspect ball joint dust cover for
damage and replace as necessary.

INSTALLATION
1) To install, reverse removal procedure. On Montero, ensure
control arm shaft is correctly positioned before installing. Rotate
control arm shaft to obtain correct measurement. See Fig. 6.

Fig. 6: Positioning Upper Control Arm Shaft (Montero)

Courtesy of Mitsubishi Motor Sales of America.

2) On Ram-50 & Pickup, install control arm-to-crossmember

bolts from the inside of crossmember, with nuts against control arm
shaft.
3) On Montero, install control arm-to-crossmember bolts from
the outside of control arm, with nuts against crossmember.
4) Ensure alignment shims are placed in original location.
When installing shock absorber, ensure White paint mark on lower end
of shock faces toward the outside of vehicle. Tighten shock absorber
upper nut until distance from end of threads to nut is .27-.31" (7-8
mm). Install shock lock nut.
5) Tighten bolts to specification. See TORQUE SPECIFICATIONS
table at end of article. Bleed brakes. Adjust anchor bolt to proper
torsion bar setting. See TORSION BAR under REMOVAL & INSTALLATION.
Check wheel alignment and adjust if necessary.

WHEEL BEARINGS R & I

REMOVAL
1) Raise and support vehicle. Remove wheel assembly. Remove
caliper assembly. Remove locking hub. See LOCKING HUB under REMOVAL &
INSTALLATION.
2) Remove lock washer. Using Socket (MB990954), remove lock
nut. Remove front hub assembly from steering knuckle.
3) Remove oil seal and bearings from hub. If bearing races
need to be replaced, drive bearing races from hub using brass drift
and hammer.

INSTALLATION
1) Before installing, lubricate outside surfaces of bearing
outer races with grease. Install bearing outer races in hub. Ensure
bearing races are fully seated.
2) Pack bearings with grease. Install inner bearing in hub.
On Montero, install seal in hub using Seal Installer (MB990955). On
Pickup, use Seal Installer (MB990985).
3) Install seal until seal is even with hub surface. To
complete installation, reverse removal procedure. Adjust wheel
bearings. See WHEEL BEARINGS under ADJUSTMENTS & INSPECTION. Tighten
bolts to specification. See TORQUE SPECIFICATIONS table.

TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS TABLE


















































Application Ft. Lbs. (N.m)

Anchor Bolt Lock Nut ............. 29-36 (39-49)

Automatic Hub Cover .............. 13-25 (18-34)
Ball Joint Nut
Lower ....................... 87-130 (118-176)
Upper .......................... 43-65 (58-88)
Ball Joint-to-Lower
Control Arm Bolt ............... 39-54 (53-73)
Caliper Bolt ..................... 58-72 (79-98)
Control Arm-to-Frame Bolt
Lower ................. (1) 101-116 (137-157)
Upper ......................... 72-87 (98-118)
Locking Hub-to-Hub/Rotor Bolt .... 36-43 (49-58)
Manual Hub Cover Bolt .................. 10 (14)
Shock Absorber Lower Mount Bolt
Montero ........................ 11-16 (15-22)
Ram-50 & Pickup ...................... 10 (14)
Shock Absorber Shaft Nut ......... 10-13 (14-18)
Tie Rod Nut ............................ 33 (45)
Torque Arm Bolt ................. 69-87 (94-118)

INCH Lbs. (N.m)

Stabilizer Bar Clamp Bolt ........ 84-108 (8-12)

(1) - Tighten with vehicle at normal operating

height.