The steering column shaft is attached to the gear pin-
ion. The rotation of the pinion moves the gear rack (2)
from side-to-side. This lateral action of the rack
pushes and pulls the tie rods to change the direction
of the front wheels.

Power assist is provided by an engine mounted
hydraulic pump (1), the pump supplies hydraulic fluid
pressure to the steering gear (2). All vehicles are
equipped with an oil cooler (5).

STEERING

19 - 1

DIAGNOSIS AND TESTING

POWER STEERING SYSTEM

There is some noise in all power steering systems. One of the most common is a hissing sound evident at a

standstill parking. Or when the steering wheel is at the end of it’s travel. Hiss is a high frequency noise similar
to that of a water tap being closed slowly. The noise is present in all valves that have a high velocity fluid passing
through an orifice. There is no relationship between this noise and steering performance.

STEERING NOISE

CONDITION

POSSIBLE CAUSES

CORRECTION

OBJECTIONAL HISS OR
WHISTLE

1. Steering intermediate shaft to dash panel
seal.

1. Check and repair seal at dash
panel.

2. Noisy valve in power steering gear.

2. Replace steering gear.

RATTLE OR CLUNK

1. Gear mounting bolts loose.

1. Tighten bolts to specification.

2. Loose or damaged suspension
components.

2. Inspect and repair suspension.

3. Internal gear noise.

3. Replace steering gear.

4. Pressure hose in contact with other
components.

4. Reposition hose.

5. Loose or damaged intermediate shaft or
column.

5. Inspect and repair or replace.

CHIRP OR SQUEAL

1. Loose belt.

1. Adjust or replace.

WHINE OR GROWL

1. Low fluid level.

1. Fill to proper level.

2. Pressure hose in contact with other
components.

2. Reposition hose.

3. Internal pump noise.

3. Replace pump.

SUCKING AIR SOUND

1. Loose return line clamp.

1. Replace clamp.

2. O-ring missing or damaged on hose
fitting.

2. Replace o-ring.

3. Low fluid level.

3. Fill to proper level.

4. Air leak between pump and reservoir.

4. Repair as necessary.

5. Reservoir cap not installed correctly.

5. Install reservoir cap correctly.

SCRUBBING OR
KNOCKING

1. Wrong tire size.

1. Verify tire size.

2. Wrong gear.

2. Verify gear.

19 - 2

STEERING

BINDING AND STICKING

CONDITION

POSSIBLE CAUSE

CORRECTION

DIFFICULT TO TURN WHEEL

STICKS OR BINDS

1. Low fluid level.

1. Fill to proper level.

2. Tire pressure.

2. Adjust tire pressure.

3. Steering components (ball
joints/tie rod ends).

3 Inspect and repair as necessary.

4. Loose belt.

4. Adjust or replace.

5. Low pump pressure.

5. Pressure test and replace if
necessary.

6. Column shaft coupler binding.

6. Replace coupler.

7. Steering gear worn.

7. Replace gear.

INSUFFICIENT ASST. OR POOR RETURN TO CENTER

CONDITION

POSSIBLE CAUSE

CORRECTION

HARD TURNING OR MOMENTARY
INCREASE IN TURNING EFFORT

1. Tire pressure.

1. Adjust tire pressure.

2. Low fluid level.

2. Fill to proper level.

3. Loose belt.

3. Adjust or replace.

4. Low pump pressure.

4. Pressure test and repair as
necessary.

5. Internal gear leak.

5. Replace gear.

STEERING WHEEL DOES NOT
WANT TO RETURN TO CENTER
POSITION

1. Tire pressure.

1. Adjust tire pressure.

2. Wheel alignment.

2. Align front end.

3. Lack of lubrication.

3. Inspect and lubricate suspension
compnents.

4. High friction in steering gear.

4. Replace gear.

LOOSE STEERING AND VEHICLE LEAD

CONDITION

POSSIBLE CAUSE

CORRECTION

EXCESSIVE PLAY IN STEERING
WHEEL

1. Worn or loose suspension or
steering components.

1. Inspect and repair as necessary.

2. Worn or loose wheel bearings.

2. Inspect and repair or adjust
bearings.

3. Steering gear mounting.

3. Tighten gear mounting bolts to
specification.

4. Gear out of adjustment.

4. Replace gear.

5. Worn or loose steering coupler.

5. Inspect and replace as
necessary.

VEHICLE PULLS OR LEADS TO
ONE SIDE.

1. Tire Pressure.

1. Adjust tire pressure.

2. Radial tire lead.

2. Rotate tires.

3. Brakes dragging.

3. Repair as necessary.

4. Wheel alignment.

4. Align front end.

STEERING

19 - 3

POWER STEERING FLOW AND PRESSURE

The following procedure is used to test the operation
of the power steering system on the vehicle. This test
will provide the gallons per minute (GPM) or flow rate
of the power steering pump along with the maximum
relief pressure. Perform test any time a power steering
system problem is present. This test will determine if
the power steering pump or power steering gear is not
functioning properly. The following pressure and flow
test is performed using Power Steering Analyzer Tool
kit 6815 (3) Adapter Kit 6893 and 6825A.

FLOW AND PRESSURE TEST

1. Check the power steering belt to ensure it is in

good condition and adjusted properly.

2. Connect pressure gauge hose from the Power

Steering Analyzer to Tube 6825A.

3. Connect Adapter 6826 to Power Steering Analyzer test valve end.

4. Disconnect the high pressure hose from the power steering pump.

5. Connect the tube to the pump hose fitting.

6. Connect the power steering hose from the steering gear to the adapter.

7. Open the test valve completely.

8. Start engine and let idle long enough to circulate power steering fluid through flow/pressure test gauge and to get

air out of the fluid. Then shut off engine.

9. Check fluid level, add fluid as necessary. Start engine again and let idle.

10. Gauge should read below 862 kPa (125 psi), if above, inspect the hoses for restrictions and repair as neces-

sary. The initial pressure reading should be in the range of 345-552 kPa (50-80 psi).

11. Increase the engine speed to 1500 RPM and read the flow meter. If the flow rate (GPM) is below specification,

(refer to pump specification chart for GPM) the pump should be replaced.

CAUTION: The following test procedure involves testing maximum pump pressure output and flow control
valve operation. Do not leave valve closed for more than three seconds as the pump could be damaged.

12. Close valve fully three times and record highest pressure indicated each time. All three readings must be

above specifications and within 345 kPa (50 psi) of each other.

•

Pressures above specifications but not within 345 kPa (50 psi) of each other, replace pump.

•

Pressures within 345 kPa (50 psi) of each other but below specifications, replace pump.

13. Open the test valve and turn the steering wheel to the extreme left and right positions three times against the

stops. Record the highest pressure reading at each position. Compare readings to the pump specifications
chart. If pressures readings are not within 50 psi of each other, the gear is leaking internally and must be
replaced.

CAUTION: Do not force the pump to operate against the stops for more than 2 to 3 seconds at a time
because, pump damage will result.

PUMP SPECIFICATION

ENGINE

RELIEF PRESSURE ± 50

FLOW RATE (GPM) AT 1500 RPM

3.7L & 4.7L

12411 kPa (1800 psi)

2.7 - 3.1 GPM

5.7L

12411 kPa (1800 psi)

2.9 - 3.3 GPM

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STEERING

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