Hydraulic Flow and Pressure - With HEC Fan

HYDRAULIC FLOW AND PRESSURE - WITH HEC FAN










The following procedures are used to test the operation of the power steering and hydraulic fan systems on the vehicle. This test will provide the gallons per minute (GPM) or flow rate of the power steering pump along with any maximum relief pressure. Perform test anytime a power steering system problem is present. This test will determine if the power steering pump, hydraulic fan, and power steering gear are not functioning properly. It will also determine if the flow coming out of the hydraulic fan motor is sufficient for the power steering gear. The following pressure and flow test is performed using the Power Steering Analyzer Tool kit 6815 (4) and Adapter kit 8630.





Adapter kit 8630.

FLOW TEST - FLOW FROM POWER STEERING PUMP

1. Check the power steering belt to ensure it is in good condition and adjusted properly.
2. Connect the pressure gauge hose from the Power Steering Analyzer to Tube 8630-2.
3. Connect Adapter 8630-3 to Power Steering Analyzer test valve end.
4. Disconnect the high pressure hose from the power steering pump.
5. Connect Tube 8630-2 to the pump hose fitting.
6. Connect the power steering hose from the fan motor to Adapter 8630-3.

7. Open the test valve completely.
8. Start engine and let idle long enough to circulate power steering fluid through the flow/pressure test gauge.
9. Shut off the engine and check the fluid level, add fluid ass necessary. Start engine again and let idle.
10. The initial pressure reading should be 965 - 1172 kPa (140 - 170 psi). If pressure is higher inspect the hoses for restrictions and repair as necessary.
11. Increase the engine speed to 1100 rpm and read the flow meter. The reading should be 2.8 GPM minimum, if the reading is below this specification, the pump should be replaced.

FLOW AND PRESSURE TEST - FLOW FROM HYDRAULIC FAN MOTOR TO STEERING GEAR (should be done if necessary after the Pump flow test)

1. Connect the pressure gauge hose from the Power Steering Analyzer to Fitting 8630-1.
2. Connect Adapter 8630-4 to Power Steering Analyzer test valve end.
3. Disconnect the high pressure hose from the power steering gear.
4. Connect Fitting 8630-1 to the high pressure hose.
5. Connect Adapter 8630-4 to the power steering gear.
6. Open the test valve completely.
7. Start engine and let idle long enough to circulate power steering fluid through the flow/pressure test gauge.
8. Shut off the engine and check the fluid level, add fluid ass necessary. Start engine again and let idle.
9. The initial pressure reading should be 586-793 kPa (85-115 psi). If pressure is higher inspect the hoses for restrictions and repair as necessary.
10. Increase the engine speed to 1500 RPM and read the flow meter. The reading should be 2.6 - 3.0 GPM if the reading is below this specification the fan should be replaced.

CAUTION: This next step involves testing maximum fan motor steering relief pressure. Do not leave the valve closed for more than three seconds.

11. Close the valve fully three times for three seconds and record highest pressures indicated each time. All three readings must be at fan motor steering relief pressures.
12. Open the test valve and turn the steering wheel to the extreme left and right positions against the stops. Record the highest pressure readings at each position. If pressure readings are not within 50 psi from each other, the gear is leaking internally and must be repaired.
PUMP SPECIFICATIONS