Mitsubishi Montero (2002-2004). Manual - part 429

GENERAL DESCRIPTION

TSB Revision

POWER STEERING

37A-3

.

GENERAL DESCRIPTION

M1372000100230

The vehicle uses engine speed-responsive hydraulic 
power steering.
The steering wheel has four spokes. All vehicles are 
equipped with SRS (Supplemental Restraint Sys-
tem).

The steering column has a shock absorber mecha-
nism and a tilt steering mechanism.
A vane-type oil pump with a fluid flow control system 
has been included. The steering gear and linkage is 
rack and pinion type.

CONSTRUCTION DIAGRAM

POWER STEERING DIAGNOSIS

INTRODUCTION TO POWER STEERING DIAGNOSIS

M1372008500179

Hydraulic power steering is used for all vehicles. 
Faults in the power steering can include excessive 
play of the steering wheel, difficult steering wheel 
operation, noise, vibration, and oil leaks, etc. Possi-
ble causes of these faults can include defects in the 
gear box, oil pump or steering linkage.

POWER STEERING DIAGNOSTIC TROUBLESHOOTING STRATEGY

M1372007300172

Use these steps to plan your diagnostic strategy. If 
you follow them carefully, you will be sure that you 
have exhausted most of the possible ways to find a 
power steering fault.
1. Gather information from the customer.

2. Verify that the condition described by the 

customer exists.

3. Find the malfunction by following the Symptom 

Chart.

4. Verify malfunction is eliminated.

AC000757

RETURN HOSE

PRESSURE HOSE

STEERING 
WHEEL

OIL PUMP

SUCTION HOSE

AB

STEERING COLUMN AND SHAFT

STEERING GEAR AND LINKAGE

RESERVOIR TANK

POWER STEERING DIAGNOSIS

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POWER STEERING

37A-4

SYMPTOM CHART

M1372007600173

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1: Excessive Play of Steering Wheel

.

DIAGNOSIS

STEP 1. Check for looseness at the steering shaft coupling 
section and at the steering wheel linkage.
Q: Is there any looseness?

YES : Repair or replace the part. Then go to Step 3.
NO :  Go to Step 2.

SYMPTOM

INSPECTION 
PROCEDURE

REFERENCE PAGE

Excessive play of steering wheel

1

P.37A-4

Difficult steering wheel operation (insufficient power 
assist)

2

P.37A-5

Rattling noise

3

P.37A-7

Shrill noise

4

P.37A-7

Squealing noise

5

P.37A-8

Hissing noise

6

P.37A-9

Droning noise

7

P.37A-9

Squeaking noise

8

P.37A-10

Vibration

9

P.37A-11

Oil leakage from hose connection

10

P.37A-11

Oil leakage from hose assembly

11

P.37A-11

Oil leakage from oil reservoir

12

P.37A-12

Oil leakage from oil pump

13

P.37A-12

Oil leakage from gear box

14

P.37A-12

POWER STEERING DIAGNOSIS

TSB Revision

POWER STEERING

37A-5

STEP 2. Check the steering wheel free play.
(1) With engine running (hydraulic operation), set front wheels 

straight ahead.

(2) Measure the play on steering wheel circumference before 

wheels start to move when slightly moving the steering 
wheel in both directions.

Limit: 30 mm (1.2 inches)

(3) If the free play exceeds the limit value, set steering wheel 

straight ahead with engine stopped. Load approximately 5 
N (1.1 lb) toward steering circumference and check play.

Standard value (steering wheel play with engine 
stopped): 10 mm (0.3 inch) or less

Q: Does the play exceed the standard value?

YES : Remove steering gear box and check total pinion 

torque (Refer to 

P.37A-27

.) Then go to Step 3.

NO :  There is no action to be taken.

STEP 3. Check steering wheel play.
Verify that the steering wheel play is not excessive.
Q: Is the steering wheel play excessive?

YES : Repeat from Step 1.
NO :  The procedure is complete.

INSPECTION PROCEDURE 2: Difficult Steering Wheel Operation (Insufficient Power Assist)

.

DIAGNOSIS

STEP 1. Check the power steering belt tension.

CAUTION

Perform the check after rotating the engine in the normal 
direction (one revolution or more).
NOTE: Since the auto-tensioner is used, it is not necessary to 
adjust the tension of the belt.
(1) Check that the indicator mark of the auto-tensioner is 

located between the marks shown as "A" on the tensioner 
bracket.

(2) If the mark is located out of the space "A," replace the drive 

belt.

Q: Is the indicator mark of the auto-tensioner located 

between the marks shown as "A" on the tensioner 
bracket?
YES : Go to Step 2.
NO :  Replace the drive belt or auto-tensioner. Then go to 

Step 10.

ACX01122 AB

ACX00751AB

INDICATOR MARK

A

POWER STEERING DIAGNOSIS

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POWER STEERING

37A-6

STEP 2. Check the belt for damage.
Q: Is the belt damaged?

YES : Replace the belt. Then go to Step 10.
NO :  Go to Step 3.

STEP 3. Check the fluid level.
(1)  Park the vehicle on a flat, level surface, start the engine, 

and then turn the steering wheel several times in both 
directions to raise the temperature of the fluid to 
approximately 50 

− 60°C (122 − 140°F).

(2)  With the engine running, turn the wheel all the way to the 

left and right several times.

(3) Check the fluid in the oil reservoir for foaming or milkiness. 

Check the difference of the fluid level when the engine is 
stopped, and while it is running. If the change of the fluid 
level is 5 mm (0.2 inch) or more, bleed air from the system. 
(Refer to 

P.37A-18

.)

Q: Is fluid foamy?

YES : Go to Step 4.
NO :  Go to Step 10.

STEP 4. Check for entry of air.
Q: Has air entered?

YES : Bleed the air. Refer to 

P.37A-19

. Then go to Step 10.

NO :  Go to Step 5.

STEP 5. Check each hose for crushing or twisting.
Q: Is any hose crushed or twisted?

YES : Repair or replace the hose. Then go to Step 10.
NO :  Go to Step 6.

STEP 6. Check for oil leaks.
Q: Are there oil leaks?

YES : Repair it. Then go to Step 10.
NO :  Go to Step 7.

STEP 7. Check the wheel alignment (camber and caster).
Refer to GROUP 33A, On-vehicle Service 

− Front Wheel Align-

ment Check and Adjustment

P.33A-5

.

Q: Is the camber or caster out of specification?

YES : Adjust it. Then go to Step 10.
NO :  Go to Step 8.

ACX01131

WHILE ENGINE
RUNNING

WHILE ENGINE
STOPPED

AB

FLUID FLUCTUATION