Brake Problem

[16vmk3ash]

Hi i have been having intermitent problems with my brakes since i had 3 new ABS sensors fitted about 10mth ago and i nead to sort it before my MOT runs out.

Some times when i press the brake pedal i get little movement in the pedal then it corrects itself and the pedal travels as normal. The feedback feel is kind of mechanical as if there is a pressure build up and there is also quite a loud noise (sort of grinding sound)!

Does anyone have any idea what the problem is? ABS pump, ABS ECU etc

Thanks

[AudiA8Quattro]

Check the brake servo for leaks.
What happens if you pump the pedal when the car is stationary?(with the engine on)

[Len]

Changing the ABS sensors would NOT have any effect on the performance or feel of the brakes in normal use. They only detect rotation of the wheel/driveshaft.

As 6 says and also try changing the brake fluid. Drain and flush it thoroughly, then refill with a good grade of new fluid.

[Len]

Another thought - check that the calipers are moving freely.

[16vmk3ash]

If i pump the brake pedal with the engine on it acts as it would normally!, when this problem occurs though i have to pump the pedal a couple of times or keep my foot down for the problem to correct itself.

You say drain and flush the brake fluid throughly! would i do this the same way as a car without ABS or is there different procedures?

This noise i am hearing sounds like its coming from the handbrake area, which is where the brake lines for the rear run as well i think.

[Dom Mk3]

I had something similar when I had a leaking rear cylinder...

[Len]

Then I think vr6 was right, sounds like a servo problem.

Havent done a Golf but changed the fluid on my 405 Mi16 and had no problems. Just watch that initial spurt of fluid - best to undo a bleed valve first. It is supposed to be recharged, but all I did was do a hard breaking until the ABS clicked in and had no probs since!