New discs, still judder

[wuta3]

So I had my front and rear brake discs replaced (with OEM discs) due to judder under braking (faster speed, faster judder, car and through pedal).
The discs had 40k miles on them, so figured they were due and warped. Pads were done not long before the discs (~5k miles with no issue, Ferodo DS, properly shimmed).

A thousand mile or so on the new discs were fine, but now judder is starting again. Not as bad, but certainly getting worse. Noticable over 40mph, again rotational, lateral judder felt through the car under braking. Similar to before I had the discs replaced.

Any ideas what could be the cause? After spending over 1k on discs, I really don't want to replace them unless there's recourse due to faulty parts or whatever (supplied by TPS done by a VAG specialist indy).

Thanks in advance for any ideas.

 

[domino_z]

Re balance wheels and check they’re not out of round

 

[wuta3]

Re balance wheels and check they’re not out of round

I'd have thought wheel balance issues wouldn't depend on applying the brake?

 

[Garrett 69]

Could be a worn suspension component like a bush, or worn track rods.

 

[Rommies]

Hmm doesn't sound like the discs...
Something else is wrong unless you really thrashed the discs with hard braking and no cooldown which warps the discs again.



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[Rommies]

The other possibility could be that when they installed the discs that they didn't clean the hubs properly (Meaning the brake discs doesn't sit 100% flush).



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[NHN]

The other possibility could be that when they installed the discs that they didn't clean the hubs properly (Meaning the brake discs doesn't sit 100% flush).



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Considering you're adding 120lb torque, also the discs dont allow for crap to get in between generally & you'd notice any proud fitment, that's highly unlikely, any residual copper grease would be squeezed flat.

To get warped damaged discs already, you'd notice something was wrong on fitment.

Remove discs or do on the floor, whatever, check for equal wear, put a ruler across the disc & you'll see the wear gap & if its equally flat, then its unlikely disc issues, check the pads too for any uneven wear & grooves.

Generally its single piston, unless it's s or rs, so the piston either stays on or retracts, as it cant really sit lopsided in the caliper unless its stuck, its unlikely a caliper issue as usually if its a stuck piston you just notice very quick wear or bad braking.

You'll need to start removing things to check.

 

[flybynite]

When they replaced the discs did they check the runout? Surprising how many people/places replacing discs don't even know what it means.

 

[Count Drunkula]

I had an issue years ago with ds2500 pads where the discs got so hot on track the pads left deposits on the surface of the disc which caused horrendous judder.

Getting discs skimmed sorted it but won't use ds2500 again

 

[flybynite]

I had an issue years ago with ds2500 pads where the discs got so hot on track the pads left deposits on the surface of the disc which caused horrendous judder.
Getting discs skimmed sorted it but won't use ds2500 again

Pad deposits and warped discs can be caused by the same thing, sitting on the brakes stationary when they are hot. It can keep the heat in one place and warp them and it can leave pad surface stuck to the disc. Happens more if they are not bedded in. Brembo have a bedding in procedure that can also be used to clean the discs. It can also correct mild warp. Use it a lot.

Brembo - Bedding Procedure Guide

To perform a trouble-free and quick installation of the Brembo's brakes, please follow the step-by-step installation instructions given in this page.

www.carid.com

Always used to be part of a standard 'Italian tune up'

However as these discs are new and the problem is still there, my money is on a runout problem

 

[wuta3]

Pad deposits and warped discs can be caused by the same thing, sitting on the brakes stationary when they are hot. It can keep the heat in one place and warp them and it can leave pad surface stuck to the disc. Happens more if they are not bedded in. Brembo have a bedding in procedure that can also be used to clean the discs. It can also correct mild warp. Use it a lot.

Brembo - Bedding Procedure Guide

To perform a trouble-free and quick installation of the Brembo's brakes, please follow the step-by-step installation instructions given in this page.

www.carid.com

Always used to be part of a standard 'Italian tune up'

However as these discs are new and the problem is still there, my money is on a runout problem

Yeah the judder went away after disc change, but then came back 1k miles later. I'll get it booked in for a look at.

 

[wuta3]

I had an issue years ago with ds2500 pads where the discs got so hot on track the pads left deposits on the surface of the disc which caused horrendous judder.

Getting discs skimmed sorted it but won't use ds2500 again

They're not DS2500, they're the DS performance road pads that alot of people use and were made for the RS3 IIRC.

 

[Orange225]

Sounds very similar to an issue I’m having, brakes feel fine in normal use, when they get hot they judder really bad and causes the steering wheel to shake, fist set did it on a solid 345mm vented disk, second set on brand new vented drilled 345mm disks and pads, lasted about 1000 miles until the judder started, brakes have also been on two cars, worked fine on the new car for another 1000 miles then the issue came back

 

[wuta3]

Sounds very similar to an issue I’m having, brakes feel fine in normal use, when they get hot they judder really bad and causes the steering wheel to shake, fist set did it on a solid 345mm vented disk, second set on brand new vented drilled 345mm disks and pads, lasted about 1000 miles until the judder started, brakes have also been on two cars, worked fine on the new car for another 1000 miles then the issue came back

Mine are juddering hot or cold, just normal city driving. Mainly above 40mph coming to a stop.
OEM discs and Ferodo pads that haven't had much trouble. Not getting much shake through the steering wheel directly, just the front of the vehicle.

 

[Orange225]

Mine do it hot or cold, but really noticeable when hot, feels like 6 points on the disk that are wider so it bites more at the wider points

 

[jimojameso]

As said above I expect its pad deposits on the disk. Have you given the car a really hard stop to try and clean them up a bit? I run ds performance as well.

 

[CHRS3]

Do a series of hard braking from 60/70mph down to about 10mph, brake to the point where you’re only just off hitting ABS. This will give you some information. If the juddering gets worse, it’s most likely to do with the discs etc as heat will exaggerate the issue, if it disappears, it would’ve been brake pad deposit build up like someone mentioned before. If it stays the same, then I would check suspension components etc.

There’s a possibility it could be a sticky brake calliper, to test this go for a drive on a road where you won’t have to brake much, slow down through the gears try not to brake then touch your discs/callipers. If one’s hot or warmer than the other side your pistons may be sticking and putting slight pressure on your pads to the disc in turn building a lot of heat and potentially warping your discs. It might’ve disappeared a little with the new pads as the calliper would’ve been off and pads out etc or could just be that it’s taken 1000 mile of sticking to eventually warp the disc.

I had this issue many years ago on a bmw, replaced discs and pads twice, skimmed twice but never worked. In the end I used OEM (paid the price) and it sorted it. But in your case you’re using OEM. Perhaps try OEM pads?

 

[Reckz]

it could be pad deposits or wheels rebalancing another issue could be you the tracking is off too?