Brakes / wheel overheating intermittent.

[Keggers]

Good morning all.

went off about my day in the car yesterday and noticed very quickly the car not as it usually is. The passenger seat was bouncing about and I noticed a vibration through the car. Soon after that I noticed when I took my foot off the throttle the car slowed much quicker than usual. Pulled over found the front NS when to feel very hot so assume brakes are stuck on. on the journey home the vibration and slowing down had gone! But later that day it was happening again. I’ve posted an example of the difference in front wheel temperatures on arrival back home. I’ve not had the brakes apart on this car myself but any advice where to start appreciated.

 

[g00se]

Yikes that's hot!

I wouldn't drive it if i were you.. sounds like the heat has warped the disk... defo looks like the piston within the caliper is not sliding, so binding and stuck on.

Which car/year is this? If its an S4, i have my old 2014 S4 calipers for sale (minus the carriers which I've sold), so could be a quick and easy fix...

If its a different model, you can get caliper rebuild kits for around £20ish

I'd fix the caliper first if i were you.. but prepare yourself for the cost of new front disks too :/

Hope this helps

goose

 

[Keggers]

Thanks I’ll have a look at the calliper tomorrow, first time it happened it seemed to correct its self and drove perfectly afterwards. I’ve seen a replacement calliper for around £120 but not sure how much work is involved and if it’s something I can do! I have all the gear but not much idea I’m thinking having a look at the sliders is something I can do with the calliper still in place and see if they are sticking.

 

[spartacus 68]

It's a full brake strip down to fix. Even if sliders aren't seized it's almost always the rubber dust seal (there's a metal tensioning ring) that corrodes.
Good video here from Dave Sterl, depending what it is he'll either fix or replace with a replacement caliper, but not Audi main dealer. Budweg and Febi calipers are around £80 a corner for 2.0 TDI (177PS)



You can buy repair kits from Autodoc or Audi main dealer. I've used Budweg brand and is good quality if you opt for a rebuild. You will need Granville red grease and ceramic brake grease) if you're doing it yourself. Access to a drill and rotary wire brush is very useful, flat metal file, etc. Do both sides or you can guarantee the other side won't be far behind.

If you're feeling adventurous, tackle the rear ones too. Audi don't sell a kit, but you'll find repair kits on Autodoc, plus comes with 'o' rings to seal as uses electro-mechanical handbrake.

 

[Keggers]

Purchased a new calliper today. All fitted and had a short test and seems ok. Will give it a longer run tomorrow so happy for now. Had a quick look at the old piston and the seal was ok but I did peel it open and there was a good bit of muck and rust under it.

 

[oscar21]

I've just had the same problem with mine and my post is a few down from this. I had to do both fronts on mine as they decided to seize up at more or less the same time. Mine had exactly the same symptoms, fine for the first few miles and occasionally it would go weeks without any problems but once they were warm they would bind excessively.

I replaced the fronts with these ones off ebay which seem fine

For Audi A4 2007-2015 Front Right Drivers O/S Brake Caliper 314mm Discs | eBay

For 314mm Front Discs Only. Fits Audi A4 2007-2015.

www.ebay.co.uk

I also replaced one of the rears (I did the other last year) as I think that was binding a bit and I know it had a slight hole in the dust cover so its now got 4 newish callipers on it.

For Audi A4 08-13 Rear LH Brake Calipers Electronic BRC54354 | eBay

To fit Audi A4 FWD 1.8 1995-1997 Front LH Brake Caliper Solid discs 62488. to fit Audi A4 08-13(Exc 3.2Fsi & S4) With Solid Discs & Number On Motor 3233-5478. Brake Caliper Pistons. Our dedicated and knowledgeable staff have many years of motor industry experience to help advise you through...

www.ebay.co.uk

It was a bit of a sod to bleed up afterwards though but that's probably because I just unscrewed the old one without crimping the flexi pipe or anything. However I did get an odd problem afterwards, I kept getting a parking brake error so it was obviously a problem with the new motor. Luckily I kept hold of the old motors so it should have been a quick swap back to one of them but the splined shaft was slightly bigger on the old motor and wouldn't fit into the new calliper, so I had to split the glued motor housings open, remove the gear drive from the new one and put it in the old motor housing then glue it all up again. So far no more error messages.

Just to add to this as well, I read several posts that claimed the root cause of sticking front brakes (especially the left front) on Audi B8's is the brake servo or booster rusting due to a build up of leaves etc above it blocking the drain channels, I believe its very awkward to change the servo so I was relieved to find it was just faulty callipers in the end but it doesn't do any harm to check everything is clear. I was sceptical of this problem, how could a faulty single servo affect one brake more than the other three?

Which reminds me, I need to check that the motor cover is still superglued in place.