> Max wrote: > > SWMBO says that she had to pump the brakes to stop the car > on one occasion yesterday. I'm planning to check the fluid > level and look for leaks, but I'm suspicious of the master > cylinder.
It depends. All you have said is "had to pump the brakes to stop the car" - which not specific enough. The subject line says "sinking" - and if that's the case, it's probably the master cylinder. If the pedal sinks when applying light pressure, there is either a hole or fluid is leaking past the master cylinder piston seals. If the fluid level isn't low, then it must be the master cylinder. Often - but not always - a fast, hard press on the brake pedal will still seal and the brakes will work fine. If the pedal is firm under light or heavy pressure, but has to be pumped a couple times before the brake pressure builds, it could be a wheel cylinder that is being "retracted" too far. Failing wheel bearings can cause excess wheel wobble that causes the brake pistons to be pushed back too much. A loose caliper can also cause similar symptoms. _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
