Ford Motor Co.

Pump flow and pressure tests are accomplished using a suitable flow/pressure analyzer (970-001) to determine system back pressure, pump flow, and internal leakage in the steering gear, control valve and cylinder. Prior to making these tests, assure that tire pressure, belt tension and fluid levels are proper. Check entire system for damage and note pulley size and pump model for proper vehicle application. Model identification labels are attached to the reservoir body with adhesive. HBC (Ford/TRW) pumps will have a suffix giving pump model, while HBA pumps (Saginaw) will only indicate the letters GS, GR, or GT on the tag. Reservoir must be kept full and at normal operating temperature (165-175°F) during testing. Using Figure through Figure, attach tester and proceed as follows:

1. With engine idling, note flow (A) at approximately 2 gallons per minute and pressure (B) 150 psi or less (200 psi if hydroboost equipped). On non-integral power steering, jiggle steering wheel to insure spool valve centering prior to testing. Higher than normal pressures (B) indicate line or poppet valve (Saginaw) restrictions.
2. Partially close tester valve to build pressure to 625 psi and note flow (C) to be at least equal to flow (A). Lower flow indicates further pump servicing is required.
3. Completely close and partially open valve three times noting pressure (D). (Do not allow valve to be closed for more than five seconds). Pressure readings 100 psi lower or 50 psi higher than specified indicate control valve cleaning or replacement is required.
4. Increase engine speed to approximately 1500 RPM and note flow (E) within one gallon/minute of idle flow (A). Control valve servicing will be required if flow varies beyond this amount.
5. Return engine to idle and turn steering wheel to left and right stops. Record pressure and flow (F) at stops to be nearly the same as maximum output pressure, while flow should drop below one gallon/minute (integral power steering) or 1/2 gallon/minute (non-integral). If pressure does not rise or flow does not drop as indicated, internal leakage is occurring. Steering gear or control valve and cylinder must be removed and serviced.
6. Turn steering wheel slightly in both directions and release quickly while watching pressure gauge. Needle should move from normal reading and snap back as wheel is released. A sticky or slow moving needle indicates that the rotary valve (integral) or control valve (non-integral) is sticking and requires further service.