System Pressure Test

Fig. 11 Pressure Test Connections:

During the following procedure, power steering system pressure may exceed 1200 psi. Ensure proper tool fitment prior to performing test. Exercise extreme caution or damage or personal injury may result.
1. Prior to performing pump flow and pressure tests, ensure following conditions exist:
a. Proper pump reservoir fluid level.
b. Correct tire air pressure.
c. Proper pump belt tension.
d. Correct model and vehicle pump application.
e. Correct size pulleys on pump and engine.
f. Ensure system is not damaged or leaking, repair as required.
2. The following test equipment is required:
a. Engine tachometer.
b. Thermometer: 0-300°F (17.8-148.9°C).
c. Power steering system analyzer tool No. 014-00207 or equivalent.
d. Set of adapter fittings.
3. The test procedure used in conjunction with the power steering system analyzer can be used to determine:
a. System backpressure.
b. Pump flow.
c. Steering gear internal leakage.
d. Pump relief pressure.
4. The readouts from step 3 can be used to determine which of the following conditions or components may be faulty:
a. Hose or fitting restriction.
b. Sticking gear valve.
c. Insufficient pump capacity.
d. Sticking relief valve.
e. Suspension system binding.
5. Remove pump high pressure line, then connect suitable analyzer hose adapter.
6. Thread other analyzer adapter to pump. Do not hook analyzer to gear intermediate fitting.
7. Connect analyzer hose to adapters, tighten both connections to 15 ft. lbs. maximum.
8. If required, add power steering fluid, start engine and allow to run about two minutes.
9. With engine at idle, record the following:
a. Flow, gallons per minute at 167-177°F (76-80°C).
b. Pressure, psi at 167-177°F (76-80°C), at idle with gate fully open.
c. If flow is below 1.5 gallons per minute, pump may require service, however continue test, check flow and relief pressure.
d. If pressure is above 150 psi check hoses for restrictions.
10. Partially close gate valve to build up 740 psi, observe and record flow:
a. If flow drops lower than .85 gallons per minute, disassemble pump and replace cam pack, if pressure plates are cracked or worn, replace.
11. Completely close and partially open gate valve three times. Do not allow valve to remain closed for more then five seconds. Observe and record pressure.
12. If pressure is lower than 1100 psi, replace pump check valve.
13. If pressure is above 1200 psi, pump check valve should be removed and cleaned or replaced.
14. Increase engine speed to about 1500 RPM, observe and record flow.
15. If flow exceeds 2.2 gallons per minute, pump flow control valve should be removed and cleaned or replaced.
16. Check idle speed, with engine at idle, turn steering wheel to left and right stops, record pressure and flow at stops.
17. Pressure at both stops should be about 1200 psi, flow should drop below 0.5 gallons per minute.
18. If pressure is not within specification, excessive internal leakage is indicated, remove and disassemble steering gear, replace worn or damaged parts and inspect rack piston and valve seals for damage.
19. While watching pressure gauge, turn steering wheel slightly in both directions and quickly release wheel, gauge needle should move from normal backpressure and snap back as the wheel is released. If needle returns slowly or sticks, the steering gear rotary valve is sticking.
20. Remove and disassemble steering as described under COMPONENT REPLACEMENT AND REPAIR PROCEDURES/STEERING GEAR/POWER STEERING/RACK & PINION then flush power steering hoses and pump before gear installation.
21. If problem still exists, check ball joint and linkage.
22. Disconnect and remove analyzer, then connect lines.