XSeries-forum

Hi All,

I have a E53 4.4i 2005 (approx. 50,000 miles).

Two problems I have noticed recently:

1. When parking (reverse parking) - my foot is on the brake pedal and I release slowly whilst reversing and going forward, the brakes will give up after a few pumps and the pedal will just push all the way down and the brakes won't engage - I have to use the handbrake!  Brake discs, pads and sensors are about 2-3 months old.  When braking with normal driving the brakes engage perfectly well.  Any ideas?  Not error lights and my local indy can't see why this is happening (even after plugging the car in for diagnostics).

2. Pushing down on brakes when travelling at 60-70mph the steering wheel starts shaking.  As the car slows, the shaking slows and ultimately stops.  Any ideas?

:'(

Has the system been bled using the ABS modulator cycling?  If air got into the system you have to bleed it with the proper procedure.

Other than that is the fluid level OK and any sign of brake fluid leaking - especially where the pipes emerge at the rear of the sills as that is a known corrosion site.

Another check is whether the seals have gone in the master cylinder which will allow the piston to move without applying much pressure to the actual callipers.  Loss of vacuum should make the pedal go firm rather than slack.

Other than that the shaking could be a warped disc.

Richard

Front control arms (brake reaction arms) can wear and cause a similar vibration under braking.

Other issue sounds like air in the system which can be the result of muppet mechanic syndrome