Hydraulic Pressure In P/S Circuit Check

Hydraulic Pressure in P/S Circuit Check





1. After cleaning joint of high pressure hose and P/S pump thoroughly, disconnect hose from pump and install special tool (oil pressure gauge, attachment and hose).

CAUTION: Take care not to cause damage to A/C condenser during service operation, if equipped.

Special tool
(A): 09915-77410
(B): 09915-77420
2. Check each connection for fluid leakage and bleed air.





3. With engine idling, turn steering wheel and warm up engine till temperature of fluid in tank rises to 50 - 60°C (122 - 140°F).





4. Check back pressure by measuring hydraulic pressure with engine idling and hands off steering wheel. When back pressure is higher than specified values, check control valve and piping for clogging.
Back pressure
Lower than 2000 kPa (10 kg/cm2, 142 psi)
5. Check relief pressure.





a. Increase engine speed to about 1500 r/min. (rpm). Close gauge valve gradually while watching pressure increase indicated by gauge and take reading of relief pressure (maximum hydraulic pressure). If it is higher than specified values, possible cause is malfunction of relief valve. If it is lower than specified values, possible cause is either failure of P/S pump or settling of relief valve spring.
Relief pressure when gauge value is closed
6200 - 7000 kPa (62 - 70 kg/cm2, 882 - 995 psi) for G16 engine
6700 - 7500 kPa (67 - 75 kg/cm2, 953 - 1067 psi) for J20 engine
7050 - 7850 kPa (70.5 - 78.5 kg/cm2, 1003 - 1116 psi) for H25 engine

CAUTION: Be sure not to close gauge valve for longer than 10 seconds.





b. Open gauge valve fully and increase engine speed to about 1500 r/min. (rpm). Then turn steering wheel to the left or right fully and take reading of relief pressure.
If it is higher than specified values, possible cause is malfunction of relief valve.
If it is lower than specified values, possible cause is failure in steering gear box. Replace gear box.
Relief pressure when gauge value is opened
6200 - 7000 kPa (62 - 70 kg/cm2, 882 - 995 psi) for G16 engine
6700 - 7500 kPa (67 - 75 kg/cm2, 953 - 1067 psi) for J20 engine
7050 - 7850 kPa (70.5 - 78.5 kg/cm2, 1003 - 1116 psi) for H25 engine

CAUTION: Be sure not to hold steering wheel at fully fumed position for longer than 10 seconds.