Component Tests and General Diagnostics

Test Equipment - Assembly
1. Remove nut securing existing high and low pressure pipes to steering box A.
2. Remove both banjo bolts from steering box. Collect sealing washers.
3. Release existing pipes beneath radiator to allow manipulation at steering box.
4. Connect existing low pressure pipe to steering box. Secure with banjo bolt.
5. Fit hose D to adapter block C. Fit assembly to high pressure port of steering box. Secure with banjo bolt.
6. Connect existing high pressure pipe to adapter block. Secure with banjo bolt.

NOTE: The high pressure pipe and hose D, could be transposed depending on hand of drive.

7. Fit hose G to adapter block C.
8. Connect pressure gauge F to test valve E. Connect hoses D and G to test valve E.
9. Ensure steering system is free from leaks. Maintain maximum fluid level during test.

Test Procedure

NOTE: If power steering lacks assistance, check pressure of hydraulic pump before fitting new components. Use fault finding chart to assist tracing faults.

1. A hydraulic pressure gauge and adapter is used to test the power steering system.
2. When testing the system, turn the steering wheel gradually while reading the pressure gauge.
3. With the test valve open start the engine.
4. With the engine at 1500 rev/min, turn the steering wheel. Hold on full lock.
5. Repeat pressure check in opposite lock.
6. The test pressure should be between 35 and 75 bar (507 and 1090 psi), depending on the road surface. Pressure will drop back to between 32 and 48 bar (464 and 696 psi), when held in full lock.
7. With the engine idling, release the steering wheel. Pressure should read below 7 bar (102 psi).
8. Pressures outside the above tolerances indicate a fault.
9. To determine if the fault is in the steering box or steering pump. Close the test valve, for a maximum of five seconds.

CAUTION: Pump damage will occur if test valve is closed for longer periods.

10. If the gauge does not register between 100 and 110 bar (1450 and 1595 psi) (maximum pump pressure), the pump is faulty.
11. If maximum pump pressure is correct, suspect the steering box.
12. On completion, remove the test equipment and, using new sealing washers, connect pipes to pump with banjo bolts.
M16 bolts: Tighten to 50 Nm (37 ft. lbs.).
M14 bolts: Tighten to 30 Nm (22 ft. lbs.).
13. Check fluid level.
14. Bleed power steering system.