Component Tests and General Diagnostics
DIAGNOSIS AND TESTINGWith engine Off, move steering wheel lightly in both directions without turning wheels, and measure distance along its circumference. Distance measured should be less than 1.2 inch.
STEERING FORCE
1. Place vehicle on a level surface and set steering wheel to straight ahead position.
2. Ensure tire pressure is proper, then start engine and warm power steering fluid to 122-140°F.
Fig. 2 Steering Force Inspection:
3. With engine idling, measure steering force using a spring balancer hooked to steering wheel, Fig. 2.
4. Steering force should be less than 8.8 lbs.
POWER STEERING BELT TENSION
1. Ensure belt is free of damage and fits properly in pulley groove.
2. Check belt deflection at midway point between power steering pulley and crankshaft pulley using about 22 lbs. of force.
3. Belt deflection should be 0.31-0.39 inch.
IDLE UP SYSTEM
With A/C turned Off, if equipped, turn steering wheel and ensure engine idling speed is not slowed down even when load is applied by power steering pump.
HYDRAULIC PRESSSURE IN CIRCUIT
Fig. 4 Oil Pressure Gauge Installation:
1. Thoroughly clean hose connections, then disconnect pressure hose and connect oil pressure gauge tool No. 09915-77410, or equivalent, between high pressure hose and high pressure pipe as shown, Fig. 5.
2. Fill power steering fluid reservoir and bleed system of air, refer to Air Bleeding for procedure.
3. With engine idling, turn steering wheel to right and left stops to warm fluid in reservoir to 122-140°F. Do not hold steering against stop for longer than 10 seconds or damage to components may occur.
4. With wheels straight forward and engine running at idle, check backpressure on gauge, pressure should be lower than 142 psi. If pressure is higher than 142 psi, check control valve and pipes for obstruction.
5. Increase engine speed to 1500 RPM minimum, then close gauge valve gradually while observing pressure increase and record relief pressure, which should be 640-924 psi. If pressure is higher than 924 psi, relief valve may have malfunctioned, replace steering gear components. If pressure is lower than 640 psi, power steering pump may have failed or relief valve spring setting is incorrect, replace power steering pump. Do not close gauge valve for longer than 10 seconds or damage to components may occur.
6. Open gauge valve fully and increase engine speed to 1500 RPM minimum, then turn steering wheel left or right stop and record relief pressure reading, pressure should be 640-924 psi. If pressure is lower than 640 psi, steering gear may have failed, replace gearbox. Do not hold steering against stop for longer than 10 seconds or damage to components may occur.