'97 A4 ABS coming on with light braking at slow speeds

[HTinVT]

The brakes in my '97 A4 1.8T seem to be functional, i.e. they still brake and stop the car. But is seems ABS is coming on. I feel the brakes pulsating as if I were skidding. The brake holds from a stand-still. I do not experience the ABS sensation when I brake at higher speeds (above ~15 mph). The ABS and Brake warning lights usually come on after driving for a few minutes and are not on when I restart the car. The problem seems to go away after driving for 10 minutes of so. I also here a humming sound that varies in pitch for the first few minutes of driving, but this could be unrelated.

Any help or guidance towards what the problem(s) is would be greatly appreciated.


Thanks!

[adamss24]

Hi, check rear abs sensors and see if there is play in the rear bearings...clean and refit abs sensors...also see front sensors, check if they are seated right.

[HTinVT]

I took a look at it this weekend. VAG-Com indicated there was an error from the front driver's side ABS sensor. I tried to remove the sensor but it seemed impossible to get out (a great deal of rust in the area). Any suggestions on how to remove the sensor without breaking it?

Thanks

[paul b]

Make sure the sensor isn't trapped in the suspension or in rust! That happened to my mate's and after spending almost £400 at local garages. He replaced servos and ABS pumps... when there was one wire trapped in rust. Freed it, cleaned it, it works!
Paul