Brake judder

Are you sure that the surfaces on the hub when you put the new discs on were perfectly clean? A bit of rust or something might have caused this run-out.

Rob Graham

that small an amount should be negligible in effect, but have you checked the whole disc for thickness variations. Otherwise there may be localised heat affected areas, often caused by fierce braking followed by holding the brake on when stationary. either way discs are very cheap these days.

Far more likely to be caused by suspension wear.

A new set of discs is probably cheaper though.

& checl the front suspension bushes, when they go soft they exaggerate any brake issues

Are you sure the discs were perfectly clean? any traces of oil or grease (eg. greasy fingerprints) can cause juddering which will continue long after the grease has burnt away.

did you change the pads as well?

The wheels have probably been over torqued, which is a common error, If they are factory disc's then by machining them flat will not work at all from my experience and the only way to fix the fault properly is to replace the discs.

By putting after market discs on the car I have found them to be inferior in material and warp more-so than genuine ones and don't recommend the fitment at all.

I can see no earthly engineering reason why the torque on an essentially incompressible cast iron brake disk flange located between two other incompressible items, the hub and wheel, should make a scrap of difference to its shape, especially the shape of the braking surface part which is well away from the bolt flange. Another ridiculous old wife's tale IMO which if it had any logic to it would mean that every time Quikshit do a tyre change and do the wheel nuts back up with a 3 foot bar with a gorilla swinging on it the disks would warp. I've seen plenty of overtightened wheel nuts in my time - I've never seen a warped brake disk because of them.

It's a very simple thing to test with a dial gauge and a torque wrench but I can tell you in advance what the result on the shape of the brake disk will be. Nil.

probably it is coincidental with disturbing the disc and getting dirt or rust between the mating surfaces, since the dirt is not immediately visible the overtightening is blamed.

I'd second that. I swapped my 406 disks for new Brembo items as the originals were warped - they're known for issues with warped disks.. I cleaned everything up very well - wirebrush, sandpaper, scotchbrite etc. and had the hubs cleaner than any I've ever done. Fitted it all back up and I still had brake judder. Stripped it all again, did a second clean, using a great deal of caution and what I would term the Ferris Bueller technique, and after that it all worked perfectly.

Well thats from the VW trained service adviser/technician so you can take it or leave it. I can only reiterate that this is a common problem with VW's. They use a torque socket to tighten the wheel nuts in the workshop.

You may like to contact a VW dealership to verify this irrespective of old wifes tails etc.

I think there maybe more to it than checking the rotor when the wheel has been removed. What readings do they have when the wheel is in place??

So a solid bit of steel has been warped by being clamped to another solid bit of steel?

Wish I'd a quid for every time so called warped discs are replaced when the problem is in the suspension...

More bollocks I'm afraid. I've never fitted genuine discs to any of my BMWs - always ATE from Eurocarparts. And never had or heard of problems.

No volume car maker makes their own brake parts. And most will source things like discs from more than one supplier.

Anybody who's ever dealt with a VW dealership becomes well aware of how much bollocks the "service advisors" talk though. Using a torque wrench to tighten the wheel nuts is sensible but it won't stop your brake pedal pulsing.

Although if you've ever compared a set of OEM 2.8 Capri discs with the pattern ones the OEM ones had less runout & a better surface finish. Mintex used to sell particularly s**te ones.

Thanks for the info.

Just so you know, always use a torque wrench on the wheel bolts.

I did use plenty of brake cleaner when I fitted the discs, and used a wire brush on the hubs to try to ensure they were flush.

I will check out the front suspension, although I'm fairly sure its down to the discs, as the judder started soon after they were changed.

Is 0.03mm of deviation really something I would feel through the steering wheel?

Thanks.

you wouldn't feel that IF everything else is perfect, trouble is that a tiny judder is magnified by any slight play in other components, such as steering rack, ball joints and bushes.

Ok - thanks.

Oh I'm sure there is rubbish out there. So best to stick to OEM - and usually save a fortune over maker's parts from a dealer.