Audi warped brake disk

[Peter Palmer]

Hi, I've posted this here because obviously its not a French car (but this site has the best knowledgeable people around). My Audi A4 (2012) is shaking under braking, I'm pretty certain its a warped disk as you can feel the pedal pulsating at low speeds. Thins is how do you confirm whether its the front or back?

I'm think it may be the back as although the whole car shakes I don't feel anything at all through the steering wheel, however I replaced the rear disks along with the pads about 20k miles ago due to a sticking rear calliper and I'd expect them to last a lot longer than 20k. But they were cheapo ebay ones and the opposite rear calliper did start sticking a while ago which I also replaced.

[RichardW]

Pull the handbrake on, this should tell you if it's the rear. Note that sometimes a bit of play in something in the front end can amplify any vibration. I've also had trouble with an out of round tyre causing severe vibration under braking.

[GiveMeABreak]

No, 20k is not unusual!

I've replaced all mine 2 years ago and in 6k miles, I will soon need the fronts doing again.

If the front, you should feel some of this via the steering wheel, but they really need checking by a garage - off the ground and measuring to check for warping.

Avoid going through deep water when hot, a la Rufford Ford, as this is a killer for disks.

[Peter Palmer]

Forgot I'd posted this, I cant go down the handbrake route as its an electric handbrake and if you pull the switch when you are driving it acts as an emergency brake and stops the car almost immediately.

I'm just a bit surprised that the rears have maybe warped so soon afterwards but there was a sticking calliper on one of them for a while. I suppose for another £50 I'll just try a cheapo set on the rear again and see what it does.

[Peter Palmer]

Well after changing the rear disks it became obvious it was in fact the fronts. So I changed these today and all is now well. Apart from the fact that the ABS/TC/parking brake dash lights are on. These lights came one before I changed any disks or pads though so it isn't me that's caused it. I'm wondering whether all the shaking has damaged an ABS sensor.

Sometimes multiple failures like this can be caused by a knackered battery but the voltage with the engine off measures 12.44V and about 13.5V with the engine running. I'm guessing those voltages should be ok.

Can anyone recommend a decent code scanner for Audis, I have lexia/diagbox for my Citroen and I used an Icarsoft one for my mates Mercedes that worked quite well.