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Pressure Test

NOTE: For testing vehicles, use Power Steering Analyzer (D79L-33610-A) with flow meter.
  1. Start engine and let idle. Record flow. See FLOW SPECIFICATIONS  table. If flow is below 1.6 gals./min. (6.1 L/min.) on Aerostar, Bronco II and Ranger, or 2 gals./min. (7.6 L/min.) on all others, pump may require repair. Continue test.
  2. If pressure is above 150 psi (10.5 kg/cm2 ), check hoses for restrictions. Partially close valve to build up pressure to 740 psi (51.8 kg/cm2 ).
  3. If flow drops below specifications, disassemble pump and replace cam pack. See appropriate STEERING GEAR - POWER article in the STEERING section:
    • STEERING GEAR - POWER RACK & PINION (for Aerostar)
    • STEERING GEAR - INTEGRAL POWER (for all others)
  4. Completely close and partially open gate valve 3 times. Do not close valve for more than 5 seconds. Record highest reading each time. If pressure is higher or lower than specified, repair or replace flow control valve. See appropriate PRESSURE TEST SPECIFICATIONS table.
  5. Set engine speed at 1500 RPM. Record flow. If flow varies more than 1 gal./min. (3.8 L/min.) from pressure measured in step 1), flow control valve in pump must be repaired or replaced.
  6. Turn steering wheel to left and right stops. Pressure should be nearly same as maximum relief pressure. Flow should drop below .5 gals./min. (1.9 L/min.).
  7. If pressure and flow are not as specified, steering gear is leaking internally. Remove steering gear. Remove flow control valve. Repair or replace damaged parts. Check rack piston and valve seals for damage.
  8. If pressure and flow are good, turn steering wheel slightly in both directions and release quickly while watching pressure gauge. Needle should move from normal backpressure reading and snap back as wheel is released.
  9. If gauge reacts slowly, or sticks, rotary valve in steering gear is sticking. Repair or replace rotary valve. If system is severely contaminated, both hoses, control valve, and pump must be disassembled and cleaned.

If pressure plates are cracked or worn, they must be replaced.

NOTE: If problem still exists, check ball joints, linkage and other front suspension members.
FLOW SPECIFICATIONS

Application Minimum Flow Gals./Min. (L/Min.)
Aerostar, Bronco II & Ranger 1.4 (5.3)
All Others 1.7 (6.4)
PRESSURE TEST SPECIFICATIONS (AEROSTAR)

Application Idle Pressure - psi (kg/cm2 ) Relief Pressure - psi (kg/cm2 )
Pump Model HBC-HD 740 (52) (1) 1300-1530 (91-108)
(1) Measure with steering wheel turned to extreme right or left position.
PRESSURE TEST SPECIFICATIONS (BRONCO II & RANGER)

Application Idle Pressure - psi (kg/cm2 ) Relief Pressure - psi (kg/cm2 )
Pump Model HBC-HD 740 (52) (1) 950-1230 (67-86)
(1) Measure with steering wheel turned to extreme right or left position.
PRESSURE TEST SPECIFICATIONS (EXCEPT AEROSTAR, BRONCO II & RANGER)

Application Idle Pressure - psi (kg/cm2 ) Relief Pressure - psi (kg/cm2 )
Pump Model HBC-HG 740 (52) (1) 1300-1530 (91-108)
Pump Model HBC-HN 740 (52) (1) 1350-1530 (95-108)
Pump Model HBA-HA 620 (44) (1) 1250-1450 (88-102)
(1) Measure with steering wheel turned to extreme right or left position.
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