Operation CHARM: Car repair manuals for everyone.

Check Valve

Hydraulic Fluid Accumulator, check valve, checking

Test condition:
- no leaks in brake servo unit

Work sequence

- with engine not running, press brake pedal about 20 times to reduce pressure in system




- disconnect wires on warning light switch and remove switch (arrow)




- attach pressure gauge with hollow bolt and copper washers to brake servo unit

NOTE: Attach thick copper washer between brake servo unit and banjo fitting and thin copper washer between hollow bolt and banjo fitting

- start engine and let idle until pressure gauge reads approx. 140 bar (2030 psi)
- turn ignition OFF
- pump brake pedal until pressure drops to 135 bar (1957 psi)
- operating pressure should not drop below 130 bar (1885 psi) within 5 minutes
- if pressure drop is more, check-valve is leaking. Replace pressure accumulator

- with engine not running, press brake pedal about 20 times to reduce operating pressure
- remove pressure gauge
- install brake light warning switch and reconnect wire connectors
- check all connections for leaks