Dodge Durango Service Manual » Steering » Power steering »

Description and operation. Diagnosis and testing

Description and operation

Steering system

Description

Power steering systems consist of:

  • Steering column
  • Rack and pinion steering gear
  • Belt driven hydraulic steering pump
  • Pump pressure and return hoses
  • Oil cooler

Operation

The steering column shaft is attached to the gear pinion. The rotation of the pinion moves the gear rack 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, (Fig. 1) and (Fig. 2) the pump supplies hydraulic fluid pressure to the steering gear.

Some vehicles are equipped with an oil cooler.

Fig. 1 Steering Pump, Gear And Oil Cooler - 5.2L & 5.9L Fig. 1 Steering Pump, Gear And Oil Cooler - 5.2L & 5.9L

1 - HYDRAULIC PUMP

2 - RACK AND PINION GEAR

3 - OIL COOLER

Fig. 2 Steering Pump, Gear And Oil Cooler - 4.7L Fig. 2 Steering Pump, Gear And Oil Cooler - 4.7L

1 - HYDRAULIC PUMP

2 - RACK AND PINION GEAR

3 - OIL COOLER

Diagnosis and testing

Power steering system

STEERING NOISE

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.

CONDITION POSSIBLE CAUSES CORRECTION
OBJECTIONAL HISS OR WHISTLE 1. Steering intermediate shaft to dash panel seal.

2. Noisy valve in power steering gear.

 1. Check and repair seal at dash panel.

2. Replace steering gear.
RATTLE OR CLUNK 1. Gear mounting bolts loose.

2. Loose or damaged suspension components.

3. Internal gear noise.

4. Pressure hose in contact with other components

5. Loose or damaged intermediate shaft or column

 1. Tighten bolts to specification.

2. Inspect and repair suspension.

3. Replace steering gear.

4. Reposition hose.

5. Inspect and repair or replace.
CHIRP OR SQUEAL 1. Loose belt. 1. Adjust or replace.
WHINE OR GROWL 1. Low fluid level.

2. Pressure hose in contact with other components.

3. Internal pump noise.

 1. Fill to proper level.

2. Reposition hose.

3. Replace pump.
SUCKING AIR SOUND 1. Loose return line clamp.

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

3. Low fluid level.

4. Air leak between pump and reservoir.

5. Reservoir cap not installed correctly.

 1. Replace clamp.

2. Replace o-ring.

3. Fill to proper level.

4. Repair as necessary.

5. Install reservoir cap correctly.
SCRUBBING OR KNOCKING 1. Wrong tire size.

2. Wrong gear.

 1. Verify tire size.

2. Verify gear.

BINDING AND STICKING

CONDITION POSSIBLE CAUSE CORRECTION
DIFFICULT TO TURN WHEEL STICKS OR BINDS 1. Low fluid level.

2. Tire pressure.

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

4. Loose belt.

5. Low pump pressure.

6. Column shaft coupler binding.

7. Steering gear worn.

 1. Fill to proper level.

2. Adjust tire pressure.

3 Inspect and repair as necessary.

4. Adjust or replace.

5. Pressure test and replace if necessary.

6. Replace coupler.

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.

2. Low fluid level.

3. Loose belt.

4. Low pump pressure.

5. Internal gear leak.

 1. Adjust tire pressure.

2. Fill to proper level.

3. Adjust or replace.

4. Pressure test and repair as necessary.

5. Replace gear.
STEERING WHEEL DOES NOT WANT TO RETURN TO CENTER POSITION 1. Tire pressure.

2. Wheel alignment.

3. Lack of lubrication.

4. High friction in steering gear.

 1. Adjust tire pressure.

2. Align front end.

3. Inspect and lubricate suspension compnents.

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.

2. Worn or loose wheel bearings.

3. Steering gear mounting.

4. Gear out of adjustment.

5. Worn or loose steering coupler.

 1. Inspect and repair as necessary.

2. Inspect and repair or adjust bearings.

3. Tighten gear mounting bolts to specification.

4. Replace gear.

5. Inspect and replace as necessary.
VEHICLE PULLS OR LEADS TO ONE SIDE. 1. Tire Pressure.

2. Radial tire lead.

3. Brakes dragging.

4. Wheel alignment.

 1. Adjust tire pressure.

2. Rotate tires.

3. Repair as necessary.

4. Align front end.

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 (Fig. 3) and (Fig. 4) Adapter Kit 6893.

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 6844.

(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.

Fig. 3 Analyzer With Tube and Adapter For 5.2L & 5.9L Fig. 3 Analyzer With Tube and Adapter For 5.2L & 5.9L

1 - GAUGE HOSE

2 - TUBE

3 - ADAPTER FITTINGS

4 - ANALYZER

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

Fig. 4 Analyzer With Tube and Adapter For 4.7L Fig. 4 Analyzer With Tube and Adapter For 4.7L

1 - TUBE

2 - ADAPTER FITTINGS

3 - ANALYZER

4 - GAUGE HOSE

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 Power steering pump

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