Braking Issue

[renegade802]

ive got the galaxy 1.9tdi 1999 model. the problem is when braking the car brakes normally until the last couple of seconds before it stops and then you get what can only be described as a buzzing through your foot on the brake pedal. like i said it only does this at low speeds just before the car comes to a halt. it feels like the abs is trying to kick in but why would it do this at such low speeds and not at high speeds or all the time even.

[chrispb123456]

As I said on your previous post check for fault codes.

Does your ABS warning light work correctly showing no fault

[sparky Paul]

By strange coincidence, I have the very same problem.

 

I changed a front ABS ring and sensor today, ABS light went out as expected and all seemed well... however, the car has developed the same issue described above. When braking, there is sometimes a buzzing/growling for a second or two just as the car comes to a stop, together with a the sound of a something whirring. I can feel the buzzing through the brake pedal, and I can hear it coming from the N/S area around the ABS pump. I'm guessing the ABS pump is doing something peculiar.

 

The feel through the pedal is not the normal ABS judder, much lighter and faster - more of a buzz. Braking doesn't seem to be affected, and ABS light stays off.

 

I'll connect VAG-COM and see if I can see anything on there, but any ideas would be gratefully received...

[sparky Paul]

Problem fixed. ;)

 

Connected VAG-COM, although ABS light out, fault was still recorded - "Front right sensor - signal outside specifications - Intermittant", or something similar. Reset fault codes, and this didn't come back after driving, so I guess it was a residual from the original problem. More importantly, buzzing/growling has stopped.

 

Just had a bit of a google, found something interesting on an Audi forum. It says you can get this symptom if the air gap is too large between a sensor and the reluctor ring, so that might be something the OP needs to look at. As Chris says, VAG-COM is the first port of call.

[sparky Paul]

Problem not fixed. :)

 

Although I tried everything, I couldn't make the problem resurface yesterday. However, it did it again today, first touch of the brakes.

 

Anyway, bearing in mind the info from the Audi forum, I had a feel around the sensor. Sure enough, there was a fingernail gap between the sensor shoulder and the hub, and the sensor gap did look a bit wide... took the sensor out, and removed about 1mm thickness of rust scale from the hub, gave the hole another clean and refitted the sensor. Now it's seated properly, it's much closer to the reluctor ring, and the problem seems to be gone... hopefully, this time for good.

[renegade802]

Thanks for the replies. i bought a vag-com lead off ebay and connected it to my car and there is no abs faults recorded. i think im gonna have to get my hands dirty and try takin the sensors off and cleaning/reseating them. is urs ok now paul??

[sparky Paul]

Yes, the problem hasn't come back, so I'm sure it's now fixed.

 

What I would do is get the torch and have a good look at the ABS rings and the sensor gaps, you might be able to pick out the bad one.