Steering: Testing and Inspection
STEERING CONDITION
B: MEASUREMENT OF HYDRAULIC PRESSURE
CAUTION:
- Be sure to complete all items aforementioned in "STEERING CONDITION", prior to measuring hydraulic pressure. Otherwise, pressure can not be measured correctly.
- Do not leave the valve of pressure gauge closed or hold the steering wheel at stop end for 5 seconds or more in any case, as the oil pump may be damaged due to long keep of these conditions.
- Put cotton cloth waste at a place where fluid drops before pressure gauge is installed. Wipe off spilt fluid thoroughly after the measurement.
NOTE: Keep engine idling during the measurement.
1B1: MEASURE REGULAR PRESSURE.
1. Install STs to power steering pump.
1. Drain the power steering fluid about 0.35 l (0.4 US qt. 0.3 Imp qt) from oil tank.
2. Remove two bolts securing power steering pipes to engine.
3. Install ST1, 2 and 3 between power steering pump and pipes using gasket (Part No. 34621AC020) and bolt (Part No. 34620AC010).
ST1 925711000 PRESSURE GAUGE
ST2 34099AC020 ADAPTER HOSE B
ST3 34099AC010 ADAPTER HOSE A
4. Replenish power steering fluid up to specified level.
2. Open valve, and start the engine.
3. Measure regular pressure.
Is pressure 981 kPa (10 kg/cm2, 142 psi) or less?
Go to step 1B2.
Trouble may be due to crushed pipe or hose, leakage from fluid line, foreign particles in fluid line, etc. Replace faulty parts with new ones.
1B2: MEASURE RELIEF PRESSURE.
1. Using STs, measure relief pressure.
ST1 925711000 PRESSURE GAUGE
ST2 34099AC020 ADAPTER HOSE B
ST3 34099AC010 ADAPTER HOSE A
2. Close valve.
is pressure 7,159 - 7,748 kPa (73 - 79 kg/cm2, 1,038 - 1,123 psi)?
Go to step 1B3.
Trouble may be due to malfunctioning relief valve, fluid leaking into oil pump interior, abnormal wear of pump vanes, etc. Replace faulty parts with new ones.
1B3: MEASURE WORKING PRESSURE.
1. Using STs, measure working pressure.
ST1 925711000 PRESSURE GAUGE
ST2 34099AC020 ADAPTER HOSE B
ST3 34099AC010 ADAPTER HOSE A
2. Open valve.
3. Measure working pressure of control valve by turning wheel from stop to stop.
is pressure 7,159 - 7,748 kPa (73 - 79 kg/cm2, 1,038 - 1,123 psi)?
Measure steering force.
Control valve is inoperative. Replace control valve itself or control valve and pinion as a single unit with new ones.
C: MEASUREMENT OF STEERING EFFORT
1. Measurement of steering effort is as shown in the figures.
2. Measurement of folding torque of universal joint is as shown in the figures.
3. Using ST, measure resistances of gearbox.
ST 926230000 SPANNER
Rotating resistance: Straight-ahead position within 30 mm (1.18 inch) from rack center; Less than 11.18 N (1.14 kg, 2.51 lb)
Maximum allowable torque; 12.7 N (1.3 ka. 2.9 lb)
Sliding resistance: Bight-turn steering; 304 N (31 kg, 68 lb) or less
Left-turn steering; 304 N (31 kg, 68 lb) or less
D: FLUID LEAKAGE
CAUTION: It is likely that although one judges fluid leakage, there is actually no leakage. This is because the fluid spilt during the last maintenance was not completely wiped off. Be sure to wipe off spilt fluid thoroughly after maintenance.
E: NOISE AND VIBRATION
CAUTION: Don't keep the relief valve operated over 5 seconds at any time or inner parts of the oil pump may be damaged due to rapid increase of fluid temperature.
NOTE:
- Grinding noise may be heard immediately after the engine start in extremely cold condition. In this case, if the noise goes off during warm-up there is no abnormal function in the system. This is due to the fluid characteristic in extremely cold condition.
- Oil pump makes whine or growl noise slightly due to its mechanism. Even if the noise can be heard when steering wheel is turned at stand still there is no abnormal function in the system provided that the noise eliminates when the vehicle is running.
- When stopping with service brake and/or parking brake applied, power steering can be operated easily due to its light steering effort. If doing so, the disk rotates slightly and makes creaking noise. The noise is generated by creaking between the disk and pads. If the noise goes off when the brake is released, there is no abnormal function in the system.
- There may be a little vibration around the steering devices when turning steering wheel at standstill, even though the component parts are properly adjusted and have no defects.
Hydraulic systems are likely to generate this kind of vibration as well as working noise and fluid noise because of combined conditions, i.e., road surface and tire surface, engine speed and turning speed of steering wheel, fluid temperature and braking condition.
This phenomena does not indicate there is some abnormal function in the system.
The vibration can be known when steering wheel is turned repeatedly at various speeds from slow to rapid step by step with parking brake applied on concrete road and in "D" range for automatic transmission vehicle.
F: CLEARANCE TABLE
CAUTION: This table lists various clearances that must be correctly adjusted to ensure normal vehicle driving without interfering noise, or any other
G: BREAKAGE OF HOSES
CAUTION: Although surface layer materials of rubber hoses have excellent weathering resistance, heat resistance and resistance for low temperature brittleness, they are likely to be damaged chemically by brake fluid, battery electrolyte, engine oil and automatic transmission fluid and their service lives are to be very shortened. It is very important to keep the hoses free from before mentioned fluids and to wipe out immediately when the hoses are adhered with the fluids.
Since resistances for heat or low temperature brittleness are gradually declining according to time accumulation of hot or cold conditions for the hoses and their service lives are shortening accordingly, it is necessary to perform careful inspection frequently when the vehicle is used in hot weather areas, cold weather area and/or a driving condition in which many steering operations are required in short time.
Particularly continuous work of relief valve over 5 seconds causes to reduce service lives of the hoses, the oil pump, the fluid, etc. due to over heat.
So, avoid to keep this kind of condition when servicing as well as driving.