BRAK E S YSTE M
1991 M it s u bis h i M onte ro
1991 BRAKES
Disc & Drum
Chrysler Motors: Ram-50;
Mitsubishi: Montero, Pickup
DESCRIPTION
Brake system consists of a master cylinder, vacuum power
brake unit, proportioning valve and self-adjusting assembly. Pickup
and Ram-50 models have a Load-Sensing Proportioning Valve (LSPV). All
models are equipped with front disc brakes and rear drum brakes.
Parking brake assembly activates rear brakes.
BLEEDING BRAKE SYSTEM
BLEEDING PROCEDURES
Montero
Bleed brake system in following order: right rear, right
front and left front (one circuit handles both rear brakes).
Pickup & Ram-50
Bleed brake system in following order: right rear, left rear,
LSPV, right front and left front.
ADJUSTMENTS
BRAKE PEDAL HEIGHT & FREE PLAY
1) Separate connector from stoplight switch, and loosen lock
nut. Position switch so it does not contact brake pedal arm. Adjust
brake pedal height by rotating master cylinder push rod (yoke, if
equipped) until distance from top of brake pedal to floor board is
correct. See BRAKE PEDAL SPECIFICATIONS table.
2) DO NOT depress push rod. Tighten lock nut, and ensure
brake pedal height is within specification. Start engine to evacuate
brake booster chamber. Stop engine, and apply brake several times to
remove vacuum from brake booster.
3) Using hand pressure, depress brake pedal to measure free
play before resistance is felt. If distance is incorrect, bleed the
brake hydraulic system, and check for misadjusted brakes. Refer to the
BRAKE PEDAL SPECIFICATIONS table.
BRAKE PEDAL SPECIFICATIONS TABLE
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Free Play Pedal Height
Application In. (mm) In. (mm)
Montero ............ .12-.31 (3-8) ... 7.5-7.7 (191-196)
Pickup & Ram-50 .... .12-.31 (3-8) ........... 6.5 (166)
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LOAD-SENSING PROPORTIONING VALVE (LSPV) (Pickup & Ram-50)
Park vehicle on level surface. Remove all luggage and
passengers. Ensure lever is not against stopper bolt. Check spring
brake pedal to center shoes, and check pedal travel. Rotate brake drum
to verify free movement.
STOPLIGHT SWITCH
Loosen lock nut, and adjust switch-to-pedal arm clearance to
.02-.04" (.5-1.0 mm). Tighten lock nut. DO NOT depress master cylinder
push rod during stoplight switch adjustment.
TESTING
POWER BRAKE UNIT
Check Valve Inspection
Remove vacuum hose from power brake unit. Remove check valve
from hose (if possible). Using a vacuum pump, ensure airflow is in
direction of intake manifold only.
System Check
1) Run engine for 2 minutes, and shut it off. Depress brake
pedal several times with normal pressure. If pedal height gradually
becomes higher with successive applications, power brake unit is okay.
If pedal height remains steady, power brake unit is faulty.
2) With engine stopped, depress brake pedal repeatedly until
it's height no longer falls. Hold brake pedal down, and start engine.
If pedal moves downward slightly, power brake unit is okay. If pedal
height does not change, power brake unit is faulty.
3) With engine running, press and hold brake pedal and shut
off engine. Hold brake pedal for 30 seconds. Brake pedal height should
not change. If pedal height falls, power brake unit is faulty.
LOAD-SENSING PROPORTIONING VALVE (LSPV) (PICKUP & RAM-50)
1) Before diagnosing Load-Sensing Proportioning Valve (LSPV)\
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ensure all other brake components are operating properly. When all
other brake system components are determined to be okay, perform LSPV
test beginning with next step.
2) Ensure unladen vehicle is on level ground. Ensure lever is
not contacting stopper bolt. See Fig. 1.
3) When lever is pushed toward valve, distance from LSPV
lever hole and support hole must be 6.97-7.09 in. (177-180 mm). If
measured distance is not within specification, loosen support bolt.
Adjust support until measured distance is within specification.
4) After measured distance is within specification, connect
pressure gauges to input and output ports of LSPV. See Fig. 4. Bleed
brake system. See BLEEDING BRAKE SYSTEM .
Fig. 4: Connecting Pressure Gauges to LSPV (Pickup & Ram-50)
Courtesy of Mitsubishi Motor Sales of America.
Installation
To install, reverse removal procedure. Tighten wheel bearings
to 22 ft. lbs. (30 N.m). Loosen nut, and then retighten to 72 INCH
lbs. (8 N.m). Install cotter pin. If pin does not align, loosen nut up\
to a maximum of 30 degrees.
REAR BRAKE DRUM & SHOES
Removal
1) Raise and support vehicle. Remove wheel and brake drum.
Remove shoe return spring and brake shoe adjuster. See Fig. 8. Remove
adjusting spring, shoe retaining spring and shoe hold-down pins.
2) Remove shoe and lining assembly with parking brake lever.
Remove cable from parking lever. Remove parking brake lever snap ring,
and disengage lever from brake shoe.
Fig. 8: Exploded View of Rear Brake Assembly
Courtesy of Mitsubishi Motor Sales of America.
Installation
1) To install, reverse removal procedure. Apply Lubriplate to
backing plate bosses, adjuster assembly threads and parking brake
lever pin.
2) Set adjustment assembly so brake shoes lightly contact
brake drum. Depress brake pedal to center shoes, and check pedal
travel. Rotate brake drum to ensure free movement.
WHEEL CYLINDERS
Removal & Installation
Raise and support vehicle. Remove rear brake drum and shoes.
See REAR BRAKE DRUM & SHOES under REMOVAL & INSTALLATION. Remove wheel
cylinder and seal assembly. To install, reverse removal procedure.
Bleed brakes.
MASTER CYLINDER
Removal
Drain brake fluid from master cylinder. Remove sensor
connector (if equipped). Disconnect brake lines from master cylinder,
and install plugs to prevent brake fluid spillage. Remove master
cylinder from booster unit and separate reservoirs from housing (if
necessary).
Installation
To install, reverse removal procedure. Before installation,
check and adjust clearance between back of master cylinder piston and
power brake push rod. Refer to MASTER CYLINDER PUSH ROD under
ADJUSTMENTS. After installation, adjust the brake pedal height. Refer
to BRAKE PEDAL HEIGHT & FREE PLAY under ADJUSTMENTS. Bleed brake
system. See BLEEDING BRAKE SYSTEM .
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PR E-A LIG NM EN T C HEC KS
1991 M it s u bis h i M onte ro
Wheel Alignment
PRE-ALIGNMENT INSPECTION PROCEDURES
PRE-ALIGNMENT CHECKS
Before making wheel alignment adjustment, perform the
following checks:
1) Tires should be equal in size and runout must not be
excessive. Tires and wheels should be in balance, and inflated to
manufacturer's specifications.
2) Wheel bearings must be properly adjusted. Steering linkage
and suspension must not have excessive looseness. Check for wear in
tie rod ends and ball joints.
3) Steering gear box must not have excessive play. Check and
adjust to manufacturer's specifications.
4) Vehicle must be at curb height with full fuel load and
spare tire in vehicle. No extra load should be on vehicle.
5) Vehicle must be level with floor and with suspension
settled. Jounce front and rear of vehicle several times and allow it
to settle to normal curb height.
6) If steering wheel is not centered with front wheels in
straight-ahead position, correct by shortening one tie rod adjusting
sleeve and lengthening opposite sleeve equal amounts.
7) Ensure wheel lug nuts are tightened to torque
specifications.
RID IN G H EIG HT A D JU STM EN T
1991 M it s u bis h i M onte ro
1991-92 WHEEL ALIGNMENT
Riding Height Adjustment
Chrysler Motors: Ram-50
Mitsubishi: Montero, Pickup
RIDING HEIGHT ADJUSTMENT
Before adjusting alignment, check riding height. Ensure
vehicle is on level floor and tires are properly inflated. Bounce
vehicle several times and allow suspension to settle.
Visually inspect vehicle, from front to rear or side to
side, for signs of abnormal height. Remove extra heavy items from
passenger and luggage compartments. If riding height is not within
specification, check and repair suspension before adjusting alignment.
See RIDING HEIGHT SPECIFICATIONS (FRONT) table.
RIDING HEIGHT SPECIFICATIONS (FRONT) ( 1)
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Application (2) In. (mm)
Montero ............................ 2.80 (71.1)
Pickup 4WD & Ram-50 4WD ............ 3.07 (78.0)
(1) - Ensure tire inflation is correct and vehicle
is level.
( 2) - Distance between lower control bump stopper
and bracket. See Fig. 1.
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RIDING HEIGHT SPECIFICATIONS 1992 (FRONT) ( 1) \
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Application In. (mm)
Montero .................. 0.83-0.91 (21.0-23.0)
Pickup 4WD & Ram-50 4WD ............ 3.11 (79.0)
(1) - Distance between lower control bumper and
bracket.
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Fig. 1: Measuring Front Riding Height (Typical 4WD)
Courtesy of Mitsubishi Motor Sales of America.
adjuster bent ......... A ............ (4) Require repair or
replacement of adjuster.
Torsion bar adjuster
seized ................ A .... ( 4) Require repair or replacement
of adjuster.
Torsion bar adjuster
threads damaged ....... A .... ( 4) Require repair or replacement
of part with damaged threads.
Torsion bar adjuster
threads stripped
(threads missing) ..... A ...... Require replacement of part
with stripped threads.
Vehicle suspension height
not within OEM
specifications ........ B ............ Require adjustment or
replacement.
( 1) - If vehicle is within manufacturer's height
specifications, no service is suggested or required.
( 2) - Some manufacturers require replacement under these
conditions.
( 3) - Check vehicle ride height. If ride height is OK, no
service is suggested or required.
( 4) - Only required if ride height needs to be adjusted.
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STEEL POWER STEERING LINES
CAUTION: When replacing steel power steering lines, be sure to use
a replacement product that meets or exceeds OEM design
specifications.
STEEL POWER STEERING LINE INSPECTION
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Condition Code Procedure
Attaching hardware
bent ................... B ... Require repair or replacement
of bent part.
Attaching hardware
broken ................. A ... Require replacement of broken
part.
Attaching hardware
loose .................. A ... Require repair or replacement
of loose part.
Attaching hardware
missing ................ C .. Require replacement of missing
part.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of part with damaged threads.
Attaching hardware
threads stripped
(threads missing) ...... A ..... Require replacement of part
with stripped threads.
Blocked ................. A .. Require repair or replacement.
Fitting incorrect
(such as compression
fitting) ............... B ............ Require replacement.
Flare type incorrect .... B ........... Required replacement.
Leaking ................. A ........... Require tightening or
replacement.
Line type incorrect ..... B ............ Require replacement.
if possible. If proper
adjustment cannot be obtained,
require repair or replacement
of worn component.
Wheel bearing race
is loose in the
hub bore ............... A ...... Require replacement of hub
assembly and wheel bearings.
Wheel bearing races
are pitted ............. A .. Require replacement of bearing
assembly.
Wheel bearing races
are worn ............... A .. Require replacement of bearing
assembly.
Wheel bearing rollers
are pitted ............. A .. Require replacement of bearing
assembly.
Wheel bearing rollers
are worn ............... A .. Require replacement of bearing
assembly.
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WHEEL ALIGNMENT
WHEEL ALIGNMENT
Wheel alignment is defined as the measurement, analysis, and
adjustment of steering and suspension angles to conform to OEM
specifications. These angles usually include, but are not limited to:
caster, camber, toe, and thrust angle. Where these angles are not
adjustable and not in specification, component replacement or
correction kits may be required. Errors in set-back and steering axis
inclination (SAI) are often attributable to failed or damaged
components and must be corrected prior to performing an alignment.
Failure to replace or correct suggested parts or service may
prevent a proper alignment.
Before performing an alignment check, inspect and verify the
following:
* Tire pressure and size
* Vehicle loading
* Ride height
* Steering and suspension parts
If the inspection reveals that all the above are within
published specifications, a wheel alignment check and an alignment, if
needed, may be performed.
CAUTION: Under no circumstances should a technician bend or heat
any steering or suspension component, unless specified by
the vehicle manufacturer, for example, Ford forged twin
"I" beam axles. All measurements and specifications must
be noted on the inspection report.
WHEEL ALIGNMENT INSPECTION
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Condition Code Procedure
Dog tracking, shown
to be caused by
faulty alignment ....... 2 ................ Suggest repair.
Lead, shown to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
BASIC FWD AXLE SHAFTS & CV JOINTS TROUBLE SHOOTING CHART
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CONDITION POSSIBLE CAUSE \
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Grease Leaks CV boot torn or cracked \
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Clicking Noise on Cornering Damaged outer CV \
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Clunk Noise on Acceleration Damaged inner CV \
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Vibration or Shudder Sticking, damaged or worn CV
on Acceleration Misalignment or spring height
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STEERING & SUSPENSION
MANUAL STEERING GEAR TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
BASIC MANUAL STEERING GEAR TROUBLE SHOOTING CHART
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CONDITION POSSIBLE CAUSE CORRECTION \
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Rattle or Rack and pinion mounting Tighten all mounting
Chucking Noise bracket loose bolts
in Rack and
Pinion Lack of/or incorrect Correct as necessary
lubricant
Steering gear mounting Tighten all mounting
bolts loose bolts
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Excessive Play Front wheel bearing See FRONT SUSPENSION
improperly adjusted article
Loose or worn steering See STEERING LINKAGE
linkage article
Loose or worn steering See MANUAL STEERING
gear shift GEAR article
Steering arm loose on See MANUAL STEERING
gear shaft GEAR article
Steering gear housing Tighten all mounting
bolts loose bolts
Steering gear adjustment See MANUAL STEERING
too loose GEAR article
Steering arms loose on Tighten and check