Check the check valve

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Checking Function Of Check Valve

Courtesy of VOLVO CARS OF NORTH AMERICA.

Check the function of the check valve.

Start the engine.

Remove the check valve from the power brake booster.

Check that there is a vacuum. Feel the check valve.

Reinstall the check valve.

Press the vacuum hose. Listen for a leak. Replace the rubber bushing if there is a leak.

Switch off the engine.

NOTE: Replace a defective check valve .

Check the function after replacing the check valve

Depress the brake pedal several times to so that it has no travel.

Hold the pedal down. Start the engine. The pedal should travel and feel softer.

Release the brake. switch off the engine. Wait 1 minute. Then depress the pedal. The pedal should still feel soft but should become stiffer when it is depressed several times.

Reinstall the positive cable holder. Tighten the nuts. Tighten to 10 Nm .

Reinstall the positive cables and nut. Tighten to 25 Nm .

Tighten the nuts