Strange noise when braking! ABS unit?
 

I have just had the rear brake pads & discs replaced on my 97' A4 1.8SE. Now if i brake until I come to stop, at the point of stopping there is a strange twanging noise coming from the front of the car, almost sounds like a spring. I can also feel the brake pedal being pushed up slightly.
The ABS light came on for a short while, while it was on this sound stopped.
Took the car back to the garage, they cleaned up all the sensors and brakes. Driving home the sound had gone! Took it through the car wash, next thing I know the sound had returned, god damn audi's!
Any suggestion on what might be causing this please, its driving me crazy. Trip to the audi specialist garage was a 50 mile round trip, I dont intend on going back again. [:@][/size]

RE: Strange noise when braking! ABS unit?
 

air in the system

RE: Strange noise when braking! ABS unit?
 

Thanks for your reply. Something so simple? The thought did cross my mind, but these guys in the garage are meant to be audi specialists! I explained the problem to him so I'm surprised he didn't pick it up. duh useless garage.
Is it simple to bleed the system? Not something I have attempted before...

RE: Strange noise when braking! ABS unit?
 

If they didnt bleed your brake fluid when they did the pad/rotor change, i dont see how air could have all of a sudden got in there if it was fine before... When he replaced your pads, he may not had taken the cap off of the resevoir, and there is backed up pressure in the lines Better take care of that FAST or you could rupture your brake lines!!!! Id just take the cap of the resevoir and pump the brakes with the car on a few times, if you see the fluid level go down in the resevoir when you are done, that was the problem, i think.

RE: Strange noise when braking! ABS unit?
 

Thanks onepoint8tee. As far as i know he didn't bleed the system. Your right, they were fine before so it seems strange. I'll try your suggestion when I get home. I contacted another garage they said it might need pressure bleeding with the help of a machine! Another £25....and so the bottomless Audi money pit of 2006 begins. I'll post what happens later.

RE: Strange noise when braking! ABS unit?
 

pressure bleeding is the best way, problem with dealer mechanics is they try to do things and cheat this gives them a bonus sort of thing, and its quite easy to get air into the system when changing the rotors and pads ( especially the rear ones )

RE: Strange noise when braking! ABS unit?
 

Well I tried the remove the reservoir cap and pump the brake idea, and yes it did have an effect, the fluid didn't really drop but the noise seemed to have gone. That was until i pulled onto the parking lot at work this morning, as i turned into a space and stopped it made the noise once again. So although the idea hasn't solved the problem, it has improved, thanks again for that!
I'll take it along to a local garage next week for the pressure bleed, hopefully that will cure it completely. I'll post the result!
I know what you mean avant, the stealership always likes to do things by halfs to ensure a return trip a week later & extra charges. Scumbags.

RE: Strange noise when braking! ABS unit?
 

I also have the same problem. Haven't had much time to look at it, but it does it at less then 5mph when slowing down and does it every time. Hopefully one of us will figure it out. My ABS light never comes on though but it feels like it's kicking in because the pedal moves as well. let me know if you figure out what it is.

RE: Strange noise when braking! ABS unit?
 

I still haven't figured this problem out : (
After speaking with a mechanic about pressure bleeding, he told me it was pointless, because if there was air in the system the pedal would go to the floor, not cause this strange sound!
So I'm back to the start. Anyone else got any ideas? If you figure it obie21202 please please let me know, its driving me crazy, How long has your A4 had the problem?
The last resort will have to be the stealership.
My last trip to the stealership I got my own back on the bastards, £500+ worth of warranty work, not bad for an 8 year old car haha.

RE: Strange noise when braking! ABS unit?
 

Pad retaing spring or circular heat shield might be loose.