Hydraulic Fluid Regulator: Testing and Inspection

CHECKING FUNCTION OF POWER FLOW REGULATOR:
- Discharge the hydraulic reservoir by operating the brake pedal about 20 times with the engine stopped and a force equal to full stop braking.
- Pull off wires and unscrew hydraulic switch.
- Mount Special Tools 34 3 160 and 32 4 005.

Installation Note: Tightening torque = 18 Nm (13 ft lb).





- Connect pressure tester 32 4 000 or alternatively 54 3 100 on Special Tools 34 3 160 and 32 4 005.





- Start engine. Pressure continues rising up to the upper switching off pressure.

Upper switching off pressure = 52-57 bar (764-838 lb sq in).

- Drop the reservoir pressure (pressure gauge) to switching on pressure by operating the brake pedal with the engine running.

Lower switching on pressure = 36-41 bar (529-603 lb sq in).

Afterwards the power flow regulator switches again to "charging reservoir" (pressure rises again). If test values are not reached, replace the power flow regulator.

- With engine off, drop the reservoir pressure (pressure gauge) to zero by operating the brake pedal about 20 times.
- Remove pressure tester and check oil level in supply tank.