Pinpoint Tests

PINPOINT TEST A: STEERING VERY DIFFICULT OR VERY EASY

A1 INSPECT TIRES

• Check tire pressure for overinflation or underinflation.

A2 CHECK DRIVE BELT

• Check condition and tension of drive belt.

A3 CHECK POWER STEERING PUMP

• Check power steering fluid condition and level.
• Check power steering pump for leakage.
• Perform power steering Pump Flow and Pressure Tests.

A4 SUSPENSION

• Check for broken or sagging springs on front and rear suspension.

A5 STEERING LINKAGE

• Visually check linkage with assistant turning steering wheel from stop to stop. Check for binding or lack of smooth operation.

A6 STEERING PIVOT TESTING

• Check ball joints or spindle pins for binding, lack of lubrication or worn surfaces. Refer to Section 04-01A (4x2) or Section 04-01B (4x4).

A7 STEERING GEAR

• Check steering gear for leakage.
• Visually check steering gear operation with assistant turning steering wheel from stop to stop.
• Check steering gear mounting fasteners for loose bolts.

A8 WHEEL ALIGNMENT

• Check wheel alignment for correct caster, toe and camber. Refer to Section 04-00.

PINPOINT TEST B: PRELIMINARY INSPECTION AND LEAK TESTING

B1 PRELIMINARY CHECK

• Check the power steering pump belt tension.
• Check the tire air pressure.
• Check power steering pump for correct model and vehicle application.

B2 FLUID LEVEL CHECK, FORD C-II PUMP

NOTE: After any major power steering system component replacement, the system should be purged of all old fluid and replaced with new fluid.

NOTE: Fluid level may be checked when fluid is either hot or cold.

• If fluid is cold (approximately 24°C [75°F]), use cold full mark on dipstick.
• If fluid is hot (approximately 77°C [177°F]), use hot full mark on dipstick.

B3 FLUID LEVEL CHECK, ZF PUMP

NOTE: After any major power steering system component replacement, the old fluid should be purged and replaced with new fluid.

• Key off.
• Remove the power steering pump oil reservoir filler cap and check the level on the dipstick. Use the cold mark if fluid is at room temperature (20°C [70°F]). Use the hot marking if the fluid is at normal operating temperature (80°C [175°F]).

B4 BLEED AIR FROM SYSTEM

• Fill power steering oil reservoir.
• Operate engine until it reaches normal operating temperature.
• Turn steering wheel to the left and right several times without hitting stops.
• Recheck fluid level inpower steering oil reservoir and fill if required.

B5 EXTERNAL LEAK CHECK

• Key off.
• Wipe off power steering pump, power steering pressure hose, power steering return hose andsteering gear.
• Key on, engine running.

 CAUTION: Do not hold the steering wheel in the far left or right position, or damage to the power steering pump may result.

• Turn the steering wheel from stop to stop several times.

B6 EXTERNAL LEAK CHECK, ROSS STEERING GEAR AND ZF PUMP

• Key off.
• Wipe off power steering pressure hoses, power steering return hose, steering gear and power steering oil reservoir.
• Mix one teaspoon of oil-soluble aniline dye intopower steering oil reservoir and fillpower steering oil reservoir to specifications as required.
• Key on, engine running at 1000-1500 rpm.
• Turn steering wheel all the way to the left and right several times.

 CAUTION: Do not hold steering wheel in the far left or right position, or damage to power steering pump may result.

• Key off.

B7 FITTINGS AND O-RING LEAK INSPECTION

• Clean the outside of the steering gear, the bottom surface of the power steering pump, and all lines and fittings.

 CAUTION: Do not tighten the fittings with a standard open-end wrench.

• Tighten all fittings using a flare-nut wrench.

PINPOINT TEST C: POWER STEERING SYSTEM TESTS, F-150, F-250, F-350, F-SUPER DUTY CHASSIS CAB AND BRONCO

C1 FLOW RATE AND PRESSURE CHECK

• Remove the power steering pressure hose from the power steering pump and connect it into the appropriate adapter of the analyzer.
• Thread the other adapter of the analyzer into the power steering pump.
• Connect the analyzer to the adapters and tighten both to 20 Nm (15 lb-ft).

NOTE: The analyzer may be connected at alternate points between the power steering pump and the steering gear.

• Add power steering fluid to the power steering pump as required.
• Startengine and run at idle for approximately 2 minutes.
• Record the flow and pressure at 74-79°C (165-175°F).

C2 FLOW RATE CHECK, GATE VALVE PARTIALLY CLOSED

• Partially close the power steering pump valve and allow the pressure to build to 5102 kPa (740 psi) for C-II pump. Record the flow at 74-79°C (165-175°F).

C3 PRESSURE CHECK, GATE VALVE OPENED AND CLOSED

 CAUTION: Do not allow the power steering pump valve to remain closed for more than 5 seconds.

• Completely close and partially open the power steering pump valve three times.

 CAUTION: Do not allow fluid temperature to exceed 93.4°C (200°F) during the test. Allow fluid to cool to 54.4°C (130°F) before resuming test if overheating occurs.

• Record the pressure.

C4 FLOW RATE CHECK, ENGINE RUNNING AT 1500 RPM

• Increase engine speed to 1500 rpm.
• Record free flow rate and compare it with the flow rate measured in Step C1.

C5 PRESSURE AND FLOW RATE CHECK, STEERING WHEEL TURNED FROM STOP TO STOP

• Turn the steering wheel from the left stop to the right stop.
• Record the pressure and the flow rate.

C6 BACK PRESSURE CHECK

• turn steering wheel slightly in both directions and release quickly while observing the pressure gauge.

C7 BALL JOINT AND LINKAGE CHECK

• turn steering wheel slightly in both directions and release quickly while observing the pressure gauge.

PINPOINT TEST D: POWER STEERING SYSTEM TESTS, F-SUPER DUTY MOTORHOME CHASSIS VEHICLES

D1 PRELIMINARY CHECK

• Remove the pressure fitting from the power steering pump and connect it into the appropriate adapter of the analyzer.

NOTE: Be sure analyzer line atpower steering pump valve end is connected to steering gear end of vehicle power steering system.

• Connect the analyzer to the adapters and tighten both to 41-54 Nm (30-38 lb-ft).
• Add power steering fluid to the power steering pump as required.

NOTE: Check the gauge needle for excessive vibration. This indicates that air is still in the system. If so, repeat the purging procedure until excessive needle vibration no longer exists.

• Fully open shutoff valve, start engine and turn steering wheel to full left and right stops to purge air from system.
• Install thermometer inpower steering oil reservoir and connect tachometer toengine.
• Align front wheels in straight-ahead position, place transmission in NEUTRAL, and engage theparking brake control.
• Partially close pressure linepower steering pump valve until pressure rises to 5516-6900 kPa (800-1000 psi).
• Fully open power steering pump valve when fluid inpower steering oil reservoir reaches 50°C (120°F).
• Increase engine speed to 2200 rpm.
• Record flow rate and pressure at 55°C (130°F).

D2 LINE CHECK

• Check lines for kinks or obstructions.

D3 MINIMUM PUMP FLOW CHECK

• Decrease engine speed to 600 rpm.
• Slowly close power steering pump valve until pressure rises to 8274 kPa (1200 psi).
• Record flow rate at 55°C (130°F).

D4 RELIEF PRESSURE CHECK, LOW RPM

• Maintain engine speed at 600 rpm.
• close power steering pump valve. (The flow rate should be zero.)
• Record pressure.
• open power steering pump valve quickly. (Flow rate should return to normal.)

D5 FLOW RATE CHECK, POWER STEERING PUMP

• Allow power steering pump fluid to cool to 55°C (130°F).
• Increase engine speed to full governed rpm.
• close power steering pump valve . (The flow rate should be zero.)
• open power steering pump valve quickly. (Flow rate should return to normal.)
• Close and open the power steering pump valve again, but do not allow the fluid temperature to exceed 95°C (200°F).

D6 RELIEF PRESSURE CHECK

 WARNING: THE BLOCK USED IN THE FOLLOWING STEP SHOULD BE AT LEAST 25.4MM (1 INCH) THICK AND LONG ENOUGH TO BE INSERTED WITHOUT DANGER OF PINCHING FINGERS. KEEP FINGERS CLEAR OF PINCH POINTS AND BE SURE BLOCK IS SQUARE TO CONTACT POINTS.

• Place a steel block between the axle stop and the adjusting screw.
• Make sure that fluid temperature inpower steering oil reservoir is 55°C (130°F) and the shutoff valve is totally open.
• Turn the steering wheel until the axle stops contact the spacer block.

 CAUTION: Do not hold the torque on the steering wheel for more than 5 seconds after the pressure relief setting of the steering gear has been reached. The steering gear could be damaged.

• Apply sufficient torque to the power steering pump so that the power steering pump valve is completely open in the direction of the turn.

D7 INTERNAL LEAKAGE CHECK, POWER STEERING GEAR, STEERING WHEEL TURNED TO LEFT

 
• Key off. Remove plug from valve body using 26mm socket.
• Insert approximately 3-6mm of additional shims into the socket portion of the plug to raise the relief bypass valve setting above that of the power steering pump valve. Ordinary 3/8-inch outside diameter flatwashers may be used as shims.
• Key on,engine running at idle speed.
• turn steering wheel to the left until axle stop contacts spacer block.

 CAUTION: Do not hold the torque on the steering wheel for more than 5 seconds after the pressure relief setting of the steering gear has been reached. The steering gear could be damaged.

• Apply sufficient torque to the steering wheel so that the power steering pump valve is completely open in the direction of the turn.
• Record flow rate with system at pump relief level.

D8 INTERNAL LEAKAGE CHECK, POWER STEERING GEAR, STEERING WHEEL TURNED TO RIGHT

• Position the spacer block between the right side axle stop and adjusting screw.
• Repeat the test procedures in Step D7, but with the steering wheel turned to the right. Observe all cautions.