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Home >> Chevy Truck >> 2000 >> C 6500 Kodiak V8-7.4L VIN D >> Repair and Diagnosis >> Steering and Suspension >> Steering >> Testing and Inspection >> Component Tests and General Diagnostics >> Power Steering System Test

Power Steering System Test




Power Steering System Test

Tools Required
* J 26487-C Power Steering Analyzer
* J 26487-100 Power Steering Analyzer Adapters
* J 26487-200 Power Steering Analyzer Adapters
* J 28579 Power Steering Analyzer Adapters (16 mm)
* J 38799 Power Steering Analyzer Adapters (20 mm)
* J 42971 Quick Disconnect Tool

The J 26487-C tool set includes the following components:

* The 0-20 000 kPa (0-3000 psi) pressure gage
* The 5-40 lpm (0-12 gpm) flow meter
* The Gate Valve
* Hoses
* Hose Adapters





Important: The TRW Ross power steering gear includes poppet valves. The poppet valves provide an increase in steering effort at a point within 1/3 turn of the steering stop contact. This is normal operation.


1. Place a container under the steering gear or pump in order to catch the fluid when disconnecting or connecting the hoses.
2. Locate and clean the pressure hose fitting that will be disconnected. The fitting is located between the power steering pump and the power steering gear.
3. Remove the pressure hose fitting from the steering gear or the power steering pump.
4. If the vehicle is equipped with quick-connect fittings, use the J 42971 quick disconnect tool. Refer to Power Steering Hose Quick Connect Fitting Procedures.
5. If the vehicle is not equipped with quick-connect fittings and has a Saginaw steering gear, use the J 28579 at the steering gear.
6. If the vehicle is not equipped with quick-connect fittings and has a TRW Ross steering gear, use the J 38799 at the steering gear.

Caution: If the date of manufacture is earlier than 1999, use the analyzer adapters J-26487-100 in order to pressure test a power steering system with quick-connect fittings. If the date of manufacture is after January 1, 1999, use the analyzer adapters J-26487-200. Failure to use the correct adapters may result in vehicle damage and in personal injury.

7. Thread or connect the female adapter into the pressure hose.

Notice: Refer to Fastener Notice in Cautions and Notices.

8. Thread or connect the male adapter into the pump or the gear.

Tighten the threaded adapters to 40 Nm (30 lb ft).




9. Connect the analyzer hoses to the adapters.
10. Bleed the power steering system. If the analyzer has never before been used, ensure that the analyzer valve gate remains open during the bleeding procedure.
11. Refer to Power Steering System Bleeding (Remote Reservoir) Power Steering System Bleeding (Remote Reservoir)Power Steering System Bleeding (Integral Reservoir) Power Steering System Bleeding (Integral Reservoir).

Important: Throughout the following testing procedure, the letters in parentheses indicate specific pressures and flows.


Document the values of the pressures and the flows. Use the letters in parentheses as references for comparing the values.


12. Run the engine at idle speed with the gate valve open.
Record the flow (A) and the pressure (B).

* If the flow is less than 2 gpm, the pump may need repair. Continue the test.
* If the pressure is above 1 379 kPa (200 psi), inspect the hoses for any restriction.

13. Partially close the gate valve in order for pressure to build to 4 827 kPa (700 psi) of pressure. Record the flow (C).
14. Compare the values of flow (A) and flow (C).
If flow (C) drops more than 1 gpm under flow (A) then:
Important: The Hobourn model S205 and Saginaw pumps can not be overhauled. Repairs should not be attempted.


15. Replace or rebuild the pump. Refer to the appropriate procedure:

* Power Steering Pump Replacement (Hobourn with LG5 and JE4) Power Steering Pump Replacement (Hobourn with LG5 and JE4)Power Steering Pump Replacement (Hobourn with LG5 and JE3) Power Steering Pump Replacement (Hobourn with LG5 and JE3)Power Steering Pump Replacement (Hobourn with LP4 or L21 and JE3) Power Steering Pump Replacement (Hobourn with LP4 or L21 and JE3)Power Steering Pump Replacement (Saginaw with LP4 or L21 and JE3) Power Steering Pump Replacement (Saginaw with LP4 or L21 and JE3)Power Steering Pump Replacement (Saginaw with LP4 or L21 and JE4) Power Steering Pump Replacement (Saginaw with LP4 or L21 and JE4)
* Power Steering Pump Disassemble (Hobourn BB Series) Power Steering Pump Disassemble (Hobourn BB Series)Power Steering Pump Disassemble (Hobourn 600 Series) Power Steering Pump Disassemble (Hobourn 600 Series)

16. Replace the following components:

* The ring
* The rotor
* The vanes
* The O-ring seals

17. Complete the following steps in order to obtain the pressure value (D):

1. Do not close the gate valve for more than five seconds.
Partially open the gate valve.
2. Close and partially open the valve two more times.
3. Observe and record the pressure (D) each time that the gate is closed.

18. Compare the pressures (D) to the specified pressures. Refer to Power Steering Pump Specifications [1][2]Power Steering Pump.

* If the recorded pressures (D) are 690 kPa (100 psi) lower than the specified pressures, than replace the pump flow control valve.
* If the pressures (D) are greater than the low specifications and vary from each other by more than 690 kPa (100 psi) then remove and clean the pump flow control valve.
* Inspect the pump flow control valve bore for dirt or foreign materials. Clean the pump flow control valve bore.
* Inspect the system fluid for contamination. If the fluid is contaminated, disassemble and clean the steering gear and the pump before assembly.

19. Increase the engine speed from idle to approximately 1500 RPM.
Record the flow (E).
20. Compare the values of flow (A) and flow (E).
Complete the following steps if flow (E) varies by more than 1 gpm from flow (A).

* Remove and clean the pump flow control valve.
* Inspect the pump flow control valve bore for dirt or foreign materials. Clean the pump flow control valve bore.
* Inspect the system fluid for contamination. If the fluid is contaminated, disassemble and clean the steering gear and the pump before assembly.

Caution: This test can be dangerous if not performed correctly. Keep your fingers clear of steering stops and spacer block during this test. Make sure that the spacer block contacts the steering stop squarely. Contact that is not square could break the steering stop or dangerously throw or eject the spacer block.

Notice: When adding fluid or making a complete fluid change, always use the proper power steering fluid. Failure to use the proper fluid will cause hose and seal damage and fluid leaks.

Important: It is necessary to use a non-hardened 1.3 cm (0.5 inch) steel spacer on the TRW Ross power steering gear.


21. Have an assistant lightly turn the steering wheel into the left steering stop and then the right steering stop.
Use a long handle to hold the spacer in place in front of the steering stops. This action will prevent pressure relief poppets from tripping.
22. Record the pressure and the flow (F).
Verify that the following conditions exist:

* The pressures measured at the steering stops are close in value to the maximum pump output (D).
* The flow drops below 1 gpm.
If the above conditions do not exist, the steering gear is leaking internally. Repair the steering gear.

23. Perform the following actions simultaneously:

* Have an assistant turn the steering wheel slightly in both directions and then quickly release the wheel.
* Observe the pressure gage.
Under normal conditions, the needle will move from the normal back pressure reading and snap back when the wheel is released. A slow or sticking needle indicates a sticking rotary valve in the steering gear.

24. Complete the following steps if the pressure gage needle moves slowly or sticks:

* Remove the rotary valve.
* Disassemble and clean the rotary valve.
* Inspect the system oil for contamination. If the system oil is contaminated, disassemble and clean the following components:

- The gear
- The pump
Important: The Hobourn model S205 and Saginaw pumps can not be overhauled. Repairs should not be attempted.


25. Refer to the appropriate procedure:

* Power Steering Pump Replacement (Hobourn with LG5 and JE4) Power Steering Pump Replacement (Hobourn with LG5 and JE4)Power Steering Pump Replacement (Hobourn with LG5 and JE3) Power Steering Pump Replacement (Hobourn with LG5 and JE3)Power Steering Pump Replacement (Hobourn with LP4 or L21 and JE3) Power Steering Pump Replacement (Hobourn with LP4 or L21 and JE3)Power Steering Pump Replacement (Saginaw with LP4 or L21 and JE3) Power Steering Pump Replacement (Saginaw with LP4 or L21 and JE3)Power Steering Pump Replacement (Saginaw with LP4 or L21 and JE4) Power Steering Pump Replacement (Saginaw with LP4 or L21 and JE4)
* Power Steering Pump Disassemble (Hobourn BB Series) Power Steering Pump Disassemble (Hobourn BB Series)Power Steering Pump Disassemble (Hobourn 600 Series) Power Steering Pump Disassemble (Hobourn 600 Series)

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