Check the power brake booster
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.
Check if there is a vacuum to the power brake booster. Do this by removing the hose from 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.
Replace the power brake booster if the pedal feels hard and unresponsive when the engine is idling.
To replace the power brake booster on a left-hand drive car, see Power brake booster, replacing .
To replace it on a right-hand drive car, see Power brake booster, replacing .