Expedition 2WD V8-281 4.6L SOHC (1998)
Power Steering Pump: Testing and Inspection
WARNING: DO NOT TOUCH THE FLOWMETER DURING THE TEST PROCEDURE OR SEVERE BURNS AND SERIOUS
INJURY MAY OCCUR.
1. Install Power Steering Analyzer at the high pressure port of the power steering pump. Make sure the Power Steering Analyzer gate valve is fully
open.
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On some vehicles, the power steering pump high pressure port is inaccessible; Power Steering Analyzer should then be installed either at the
steering gear or at a point in the high pressure line between the power steering pump and the steering gear.
CAUTION: Ensure that the connection point will not interfere with any of the engine accessory drive components or drive belts.
2. Place Dial Thermometer in the power steering pump reservoir.
3. Check the power steering fluid level. If necessary, add power steering fluid.
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Use Motorcraft MERCON Multi-Purpose ATE XT-2-QDX or equivalent meeting Ford specification MERCON.
4. Install 88 Digital Multimeter.
5. Start the engine. Place the transmission in N (neutral). Set the parking brake. Raise the power steering fluid temperature to 74-80° C (165-175° F)
by rotating the steering wheel fully to the left and right several times.
CAUTION: Do not hold the steering wheel against the stops for more than three to five seconds at a time. Damage to the power steering pump
will occur.
6. Set the engine speed to idle. Record the flow rate and pressure readings.
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If flow rate is below the idle flow rate specification, the power steering pump may require repair. Continue with the test procedure.
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If the pressure reading is above the idle pressure specification, then check power steering hoses for kinks and restrictions.
7. Partially close the gate valve to obtain 740 psi. Record the flow rate
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If the flow rate is less than specification, replace the power steering pump.
8. Completely close and partially open the gate valve three times. Record the pressure relief valve actuation pressure reading.
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If pressure does not meet the relief pressure specification, then replace the power steering pump.
CAUTION: Do not allow the gate valve to remain closed for more than five seconds.
9. Set the engine speed to 1500 rpm. Record the flow rate.
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If the flow rate varies more than 3.785 liters/minute (1 gallon/minute) between the initial flow rate reading, then replace the power steering
pump.
10. Set the engine speed at idle. Turn the steering wheel to the left and right stops. Record flow rate and pressure readings at the stops.
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The pressure reading at both stops should be nearly the same as the maximum pump relief pressure.
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The flow rate should drop below 1.9 liters/minute (0.5 gallons/minute).
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If the pressure does not reach the maximum pump relief pressure or the flow rate does not drop below the specified value, excessive internal
leakage is occurring. Replace the steering gear.
CAUTION: Do not hold the steering wheel against the stops for more than three to five seconds at a time. Damage to the power steering pump
will occur.
11. Turn the steering wheel slightly in both directions and release quickly while watching the pressure gauge.
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The pressure reading should move between the normal back pressure reading and snap back as the steering wheel is released.
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If the pressure returns slowly or sticks, the rotary valve in the steering gear is sticking or the steering column is binding. Check the steering
column and linkages before repairing the steering gear.
