Hydraulic Pressure Testing With H-31 System
CHECKING OPERATION OF POWER STEERINGH 31 System
- Engine at Operating Temperature -
Check hydraulic fluid level in tank. Check all hose connections and equipment (pump, brake booster, power flow regulator and steering gear) for leaks before checking operation.
Discharging Pressure:
Operate brake pedal about 20 times with engine stopped.
Install pressure tester 32 4 000 between pump and power flow regulator.
1 = Power flow regulator or steering gear connection.
2 = Pump connection.
A = Shut-off valve (low pressure: 0 to 15 bar/0 to 213 psi).
Caution!
Shutoff valve (A) must always be closed for high pressure tests to avoid damaging pressure tester.
B = Shut-off valve (high pressure: 0 to 150 bar/0 to 2133 psi)
Open valve (B).
Close valve (A).
Start engine - fill hydraulic fluid in tank.
Bleeding System:
Turn steering wheel twice each against left and right locks.
Operate brake pedal 5 times, wait 30 seconds and operate pedal another 5 times.
Hydraulic fluid temperature should be approx. 50° C (122° F) for all tests.
Turning steering wheel against locks with engine running could cause a rise in temperature.
1. Checking Flow Pressure:
Open valve (B).
Close valve (A) and run engine.
Open valve (A) and read pressure when pressure is less than 15 bar (213 psi).
Max. permissible flow pressure of 8 bar (114 psi) must not be exceeded.
Pressure Greater Than 8 bar (114 psi).
2. Checking Pump:
Install pressure tester between pump and power flow regulator.
Close valve (A). Start engine.
Close valve (B) max. 10 seconds and read pressure.
Rated pump pressure 110 to 120 bar (1565 to 1705 psi) should be reached.
Rated pressure exceeded 110 to 120 bar (1565 to 1705 psi), replace pump.
Rated pressure not reached 110 to 120 bar (1565 to 1705 psi), check drive belt tightness.
Repeat test.
Rated pressure still not reached 110 to 120 bar (1565 to 1705 psi), replace pump.
3. Checking Reservoir Charging Pressure:
Pressure tester between pump and power flow regulator.
System bled.
Engine not started.
Valve (B) open.
Valve (A) closed.
Start engine and observe pressure tester.
Pressure must rise to max. 57 bar (811 psi) and then drop immediately to less than 8 bar (114 psi).
If max. permissible pressure of 57 bar (811 psi) is exceeded or there is no immediate pressure drop after reaching max. permissible pressure, replace power flow regulator.
4. Power Steering:
Pressure tester between pump and power flow regulator.
System bled.
Valve (B) open.
Valve (A) closed.
Engine not started.
Lift car.
Stop steering from reaching final left lock by 1/2 to 3/4 steering wheel turn with a piece of wood or similar item.
Start engine.
Pull steering wheel against final left lock with a force of 100 N (22 lbs.) (force meter) about 5 seconds and read pressure.
Limit final right lock and repeat test on right lock.
If pressure values are lower than pump pressure determined in point 2. replace steering gear.
5. Checking Mechanical Play of Steering:
- Pressure point adjusted.
- No play in steering column.
Pressure meter between pump and power flow regulator.
System bled
Valve (B) open.
Valve (A) closed
Engine not started.
Steering drop arm held in straight ahead position with Special Tool 32 4 040.
Paste strips of paper on steering wheel hub and casing upper section.
Make mark (center) on steering wheel hub.
Start engine.
Open valve (A).
Read flow pressure.
Turn steering wheel counterclockwise until pressure meter shows 1 bar (14 psi)more pressure than flow pressure value.
Mark position of steering wheel hub.
Repeat this in clockwise direction.
If max. permissible travel (C) = 7 mm (0.276") is exceeded, replace steering gear.
Remove special tool holder and pressure meter.
Bleed hydraulic system and, if necessary, add hydraulic fluid.