Warped discs

[ian.f]

Hi forum,
I need some help please.
I’m having issues with my B9 Avant; I’m constantly warping discs. I don’t have a heavy brake foot, so I don’t think it’s my driving style.
I’m wondering if it’s something in the brand/types of discs I’m buying. I’m usually a Bosch guy, but have used them and similar level brands, but I have to replace after about 5k.
Can anyone suggest a reason why?
Any advice appreciated

 

[spartacus 68]

To be honest, I think warped discs on a B9 car is unusual. What's the age of the car?

More likely is pad transfer. Without getting into a brand argument, but there so many decent makes out there, Pagid, ATE, Zimmerman, Brembo, etc.

Check the brake sliders that they aren't siezed, the edges on the brake carrier aren't corroded. Use a metal file to get a decent edge. Rust on the carrier will hold the pad in situ against the rotor. Use ceramic brake grease to lightly lubricate the pad edges.

If you think the pistons are siezing then drive the car for 15 mins and coast to a stop. They may be warm, but not hot. If its hot, strip the whole lot down. Autodoc do caliper rebuild kits, front and back. You need to be spanner handy and do a brake bleed afterwards.

 

[ian.f]

To be honest, I think warped discs on a B9 car is unusual. What's the age of the car?

More likely is pad transfer. Without getting into a brand argument, but there so many decent makes out there, Pagid, ATE, Zimmerman, Brembo, etc.

Check the brake sliders that they aren't siezed, the edges on the brake carrier aren't corroded. Use a metal file to get a decent edge. Rust on the carrier will hold the pad in situ against the rotor. Use ceramic brake grease to lightly lubricate the pad edges.

If you think the pistons are siezing then drive the car for 15 mins and coast to a stop. They may be warm, but not hot. If its hot, strip the whole lot down. Autodoc do caliper rebuild kits, front and back. You need to be spanner handy and do a brake bleed afterwards.

Thanks; this is brilliant.
Mine is a 2016. Very early B9 and tbh I’ve had horrendous issues with it. Spent ‘000s on repairing things I wouldn’t consider Audi’s failing on. It’s only done 65k as well. Anyway…

Thanks, I hadn’t considered the pads as an issue. I just assumed the discs were the issue.
I’ve got to replace all 4 upper control arms shortly, as all bushes have failed, so I’ll have a go at what you suggest.
Cheers

 

[45bvtc]

Hi forum,
I need some help please.
I’m having issues with my B9 Avant; I’m constantly warping discs. I don’t have a heavy brake foot, so I don’t think it’s my driving style.
I’m wondering if it’s something in the brand/types of discs I’m buying. I’m usually a Bosch guy, but have used them and similar level brands, but I have to replace after about 5k.
Can anyone suggest a reason why?
Any advice appreciated

I agree with spartacus 68, see: https://alconkits.com/support/brake-pad-info/110-the-real-truth-about-warped-brake-rotors

Had similar issues with S3 and RS3 and always friction material deposit on the brake disc.
We now use Ferodo Eco-Friction brake pads, see: https://www.ferodo.co.uk/products/light-vehicles/eco-friction-brake-pads.html
Ferodo Eco-Friction brake pads "Already fitted as Original Equipment on Mercedes-Benz C-Class since March 2014 and Audi A4 since September 2015"
Perfect for our TT, RS3 and SQ5 with similar "I don’t have a heavy brake foot" use

 

[NHN]

Get a temperature gun on the wheels & calipers after a drive & compare the temps across fronts & rears, it should give you an indication if calipers are sticking.

 

[45bvtc]

Get a temperature gun on the wheels & calipers after a drive & compare the temps across fronts & rears, it should give you an indication if calipers are sticking.

C'mon Nigel!
Q1: have you ever known modern/style/manufacture "warped ventilated brake discs?" on a road car with - "I don’t have a heavy brake foot" use
* PLEASE: put a DTI (Dial Test Indicator, tsk!) on it and you'll find none!
Q2: how many contaminated through 'lack of use' / poor/lack of 'bedding-in procedure' brake discs have you found?
* PLEASE: and in general the build -up is on the brake disc inside/cold face!
Getting way tooooo old for this! On and on and on...

 

[NHN]

Funny you should ask, as recently yes for a client that had converted his A4 to RS4 B7 Avant spec.

But yes I used a gauge on all discs & monitored the temps that proved a number of issues including warp factor 10.

Of course I can only take his word for the non heavy foot situation but he seems genuine enough & he's quite up on cars tbf, so he knows how to run in so to speak.

Tbh there were a number of situations that led to this, but it's what happened for whatever reasons.

I'll be honest the temp guns are pretty good at helping to point you in the right direction, certainly helped me.

My point was to see if he had a piston issue, not a disc issue, (although the 2 can come hand in hand) we could look at the 8P as an example, rear calipers are very regularly having stuck pistons, mine were & other clients.

 

[45bvtc]

Funny you should ask, as recently yes for a client that had converted his A4 to RS4 B7 Avant spec.

But yes I used a gauge on all discs & monitored the temps that proved a number of issues including warp factor 10.

Of course I can only take his word for the non heavy foot situation but he seems genuine enough & he's quite up on cars tbf, so he knows how to run in so to speak.

Tbh there were a number of situations that led to this, but it's what happened for whatever reasons.

I'll be honest the temp guns are pretty good at helping to point you in the right direction, certainly helped me.

My point was to see if he had a piston issue, not a disc issue, (although the 2 can come hand in hand) we could look at the 8P as an example, rear calipers are very regularly having stuck pistons, mine were & other clients.

Interesting, as ALWAYS, Nigel - so much more form HANDS-ON experience!
Ferodo Eco-Friction brake pads (and a disc scrub - INSIDE and OUTSIDE (a temp gun won't differentiate)) have resolved oh so many owner issues for me, just saying...
It is the INSIDE brake disc face(s) I always find clogged/clagged/bonded with friction material!
3-years now with Ferodo Eco-Friction and no-issues/comeback...

 

[NHN]

Me & you agree on probably all your points mate, I honestly respect your input in all your posts (no brown tongue included)

The temp gun was just as assist to know where would be best to start checking for braking issues.

It is by no means a cure or a definitive diagnosis at all, but in my experience as limited as it has been, humbly speaking, it's helped more than hindered.

You've probably just cause me a nice spend on those pads lol.

 

[45bvtc]

Me & you agree on probably all your points mate, I honestly respect your input in all your posts (no brown tongue included)

The temp gun was just as assist to know where would be best to start checking for braking issues.

It is by no means a cure or a definitive diagnosis at all, but in my experience as limited as it has been, humbly speaking, it's helped more than hindered.

You've probably just cause me a nice spend on those pads lol.

Thank you for your kind words.
I do worry about that inner dirt/splash shield finding it causes more issues than one expects; while the outside face of the brake disc looks fine the inner face can be somewhat different, like so (8P RS3 on OEM brake pads):

​

Interesting we rarely consider the inside face of the brake disc!

Go try the Ferodo Eco-Friction Nigel and if they don't work for you on yours then send me the bill!

 

[NHN]

Yeap seen that myself & also on the clients car, I generally check everywhere anyway mate as a matter of course.

Just need your address mate ;P

I'm sure they're good pads

 

[45bvtc]

Yeap seen that myself & also on the clients car, I generally check everywhere anyway mate as a matter of course.

Just need your address mate ;P

I'm sure they're good pads

PM sent...

 

[ian.f]

Thanks for the replies, I think. Not sure if I’m being supported or popped at tbh, but thems the breaks of keyboards.

I don’t have access to a temp gun, but I have had experience of sticky/jammed callipers before…and an old mechanic I trusted with every nut on any car, once told me the wheel would show higher/residual heat if there was a severe calliper issue. But of course I can’t rule it out; I’m not a trained mechanic but am spanner handy so I can follow the recommended steps and see what I find.

Thanks again

 

[45bvtc]

Thanks for the replies, I think. Not sure if I’m being supported or popped at tbh, but thems the breaks of keyboards.

I don’t have access to a temp gun, but I have had experience of sticky/jammed callipers before…and an old mechanic I trusted with every nut on any car, once told me the wheel would show higher/residual heat if there was a severe calliper issue. But of course I can’t rule it out; I’m not a trained mechanic but am spanner handy so I can follow the recommended steps and see what I find.

Thanks again

You most certainly are NOT being "popped at." Go read the 1st link I gave you post #4 and you will find yours is NOT an unusual issue.

 

[ian.f]

You most certainly are NOT being "popped at." Go read the 1st link I gave you post #4 and you will find yours is NOT an unusual issue.

Thanks; I hadn’t had a chance to read the link until this morning.
Super informative. I’ll keep all of that heavily in mind.

 

[45bvtc]

Thanks; I hadn’t had a chance to read the link until this morning.
Super informative. I’ll keep all of that heavily in mind.

You might also condider having your brake discs 'skimmed' on the car; I had this done on sevaral cars with 100% success.

Several facilities in your area, see: https://skimmydiscs.co.uk/your-nearest-service-centre

 

[ian.f]

You might also condider having your brake discs 'skimmed' on the car; I had this done on sevaral cars with 100% success.

Several facilities in your area, see: https://skimmydiscs.co.uk/your-nearest-service-centre

It’s like you read my mind. I was wondering all through today how, if there is pad material on the disc, I would deal with it.
Thanks again

 

[45bvtc]

It’s like you read my mind. I was wondering all through today how, if there is pad material on the disc, I would deal with it.
Thanks again

You said, Ian: "I’m not a trained mechanic but am spanner handy."

So why not remove the brake disc(s), carefully linish both sides, and fit a set of Ferodo Eco-Friction brake pads.

Not taking the 'Michael' honest, but have done this soooo many times it HURTS!

And am now getting way too old to want to do it again!

See photos, post #10

Had this issue since the late 60's when the powers that be banned asbestos in brake pads - this resulted in us Lotus/Marcos/TVR owners running around trying to find suitable fast-road friction materials. I digress, for me the best I've found recently (for Audi) are these Ferodo Eco-Friction brake pads and for sure they work well on our TT, RS3 and SQ5. It is what I/we use! Period!

Playtime....

 

[ub7rm]

Interesting on the strong recommendation for Ferrodo Eco pads, when I replaced the pads and discs on my b9 S4 this is what I used. But. They squeal. This isn't my first rodeo in changing pads / discs and I've never had this problem. I've had them off a couple of times to re-grease but I can't shift the noise. (Typical noise at light braking input).

To be fair this was my first brake job on a more complex caliper (past experience on a raft of GTI's / A3's) so maybe there was a contact point that I should have greased which wasn't obvious. Is this a feature of the Ferrodo's? Any tips? I struggled to get the shims to stay in the right place while fitting and harbor some suspicion that they are actually causing the squeal somehow and not, as they are designed to, reduce.

I actually have a new set of pads on the shelf in case I fitted a rogue batch but haven't found the time to try again.

 

[45bvtc]

Interesting on the strong recommendation for Ferrodo Eco pads, when I replaced the pads and discs on my b9 S4 this is what I used. But. They squeal. This isn't my first rodeo in changing pads / discs and I've never had this problem. I've had them off a couple of times to re-grease but I can't shift the noise. (Typical noise at light braking input).

To be fair this was my first brake job on a more complex caliper (past experience on a raft of GTI's / A3's) so maybe there was a contact point that I should have greased which wasn't obvious. Is this a feature of the Ferrodo's? Any tips? I struggled to get the shims to stay in the right place while fitting and harbor some suspicion that they are actually causing the squeal somehow and not, as they are designed to, reduce.

I actually have a new set of pads on the shelf in case I fitted a rogue batch but haven't found the time to try again.

Interesting, I have not had that issue with the sets of Ferodo Eco-Friction pads I have fitted - unlike the Audi/Brembo/Pagid OEM pads.
Please check that the pistons haven't worn through the antisqueal material on the back of the pad, like here with the Audi 8P RS3/Brembo/Pagid OEM pads:

Note the 'silver' worn-through the anti-squeal coating rings (after 1500 miles) - brake squeal being high-speed vibration between piston and brake-pad mounting - hense the use of anti-squeal shims.

An easy fix is to apply some self-adhesive (3M/Mintex) anti-squeal shims, like so:


And after 5000-miles, self-adhesive anti-squeal shims still working well and zero wear-through:

Hope this helps...

 

[ian.f]

Hi,
Just an update on my side. Finally got some time yesterday to get working on this.

I stripped everything down and found:
1. Very very dirty all round. Hubs, discs (non-contact points) & callipers all had significant build up.
2. Some very odd “imprints” of the pad on the disc, both sides. There wasn’t any obvious surface difference though, just looked like a colour bleed.
3. Neither of the brake fluid lines were seated in their respective holders, as they were bent out of shape badly.
4. Brake wear indicator wasn’t attached; just dangling in the wind.
5. Lots of (copper?) grease smothered everywhere.
6. The ‘spring’ mounters on the back of the pads were too pinched, and not holding in the piston.

So I proceeded to clean everything down thoroughly; pads, discs, calipers & hubs. Used a ton of brake cleaner!!
Removed debris from the pads where there was quite a bit of build up.
I also ran a sander over the disc to see if there’d be any change to the colouring. There wasn’t.
Re-fitted everything as best I could, with exception of the wear indicator as either is wrong one or is broken. Didn’t have a spare. Opened up the spring mounts so they seated in the piston well.

Result is, at 50mph and below the juddering has been eliminated. At 50-70, there is juddering, but only minimal. At 70 plus, the juddering is quite noticeable.

So, next step is new pads and discs. Pads I’ll go with the Ferrodo (as above) and I’ll see what my budget stretches to post that purchase!

 

[ultra sport A4]

Hi, wonder if anyone can help me shed light on my a4 b9 2026 ultra sport brake warped rear drivers side (uk)

It's had 3 sets of brakes now two sets of Apec Black OEM & one set padid approved even Audi dealer cannot find.

Anyway, after a rolling road test and all bearings and calipers checked, kwic fit fitted my third set padgid and say they will replace the rears again, however as this is the forth set replaced kwick fit will not replace again as the problem is clearly elsewhere, which is understandable. Anyone know of a good brake specialist in Doncaster to further investigate and get to the root cause. Only things left is caliper ( no signs of overheating and nothing untoward on inspection) and hub bearing, again no signs.

I've already replaced the lhs hub bearing as Audi said that's where the noise was coming from. This cars costing me fortune atm without a resolution.

The the disks and pads are run in correctly for more than over 100 miles, and this problem seams to present after a 3 miles or so, I don't heavily drive it, above 70 when braking the rear is noisy humming noise.

Rolling Road shows fluctuations with rear rhs.

Both rear weels show no signs of bearing movement and free of noise and play when free wheeling 4 garage opions.

Calipers was inspected when Padgid ( kwick fit fitted) and was OK.

Help please?

 

[ultra sport A4]

Hi, wonder if anyone can help me shed light on my a4 b9 2026 ultra sport brake warped rear drivers side (uk)

It's had 3 sets of brakes now two sets of Apec Black OEM & one set padid approved even Audi dealer cannot find.

Anyway, after a rolling road test and all bearings and calipers checked, kwic fit fitted my third set padgid and say they will replace the rears again, however as this is the forth set replaced kwick fit will not replace again as the problem is clearly elsewhere, which is understandable. Anyone know of a good brake specialist in Doncaster to further investigate and get to the root cause. Only things left is caliper ( no signs of overheating and nothing untoward on inspection) and hub bearing, again no signs.

I've already replaced the lhs hub bearing as Audi said that's where the noise was coming from. This cars costing me fortune atm without a resolution.

The the disks and pads are run in correctly for more than over 100 miles, and this problem seams to present after a 3 miles or so, I don't heavily drive it, above 70 when braking the rear is noisy humming noise.

Rolling Road shows fluctuations with rear rhs.

Both rear weels show no signs of bearing movement and free of noise and play when free wheeling 4 garage opions.

Calipers was inspected when Padgid ( kwick fit fitted) and was OK.

Help please?