Porsche Enthusiasts Club Forum

My S2 has suffered from brake judder for almost a year now, so last winter I decided to refurb the front callipers and change the discs and pads. After putting it all back together I noticed the discs weren't quite running parallel with the pads, but put it down to the pads needing to settle. Guess what, they never settled and I still have brake judder, although I've lost the terrible brake squeal, by adding the proper shims behind the pads.

At first I though the discs might be warped, but the old ones were still fairly new and the Pagid ones being warped out of the box? Unlikely. My next thought was the caliper mounting surface could be very slightly out of true.

So I've removed the callipers, bolted a bit of wood to the hub with a bolt through it, and screwed it till it almost touched the disc, then spun them round. They ran out of true fairly visibly with a single high point on rotation. I then swapped the old disc round and pretty much the same thing.

I've thought about getting them skimmed, but that's not curi the problem, it just means I'll need to skim every set do discs.

It sounds like I've got brake run out and seen a company in the USA who sell correction shims but I really want to fix the issue without a work around.

I've thought about the wheel bearings, but there isn't any noticeable play. My next thought is to replace the bearings just to iliminate them. I've also looked around for a complete set of hubs but not seen anything other than a pair in the USA.

I also took the car to a local garage for their opinion, but they didn't have any suggestions other than to get the discs skimmed.

Has anyone else suffered the same? If so what ended up being the issue? Any suggestions would be gratefully received.

Thanks

In most cases, rust build up on the flange disc mating surface.
Spend time and clean all traces before fitment of new discs.

^ +1

Yes done that, cleaned everything up when I stripped the hubs.

Have you checked the run out against the values in the workshop manual, they would need to be out by a considerable amount to create judder

And not just one high spot, are you sure it’s the fronts not the rears

If you can find a garage with a Pro-Cut disc lathe, they can skim the disc in situ on the car, removing high spots and compensating for any disc or hub runout or combination of both.

Yes it's 100% the fronts and it doesn't take much to feel judder, but I'd say the runout is close to 1mm, very visible.

Yes skimming is an option but as I said I'd rather fix the cause, otherwise I'll need to get it skimmed each time I replace discs, and my ocd would kick in knowing I've still got an underlying problem.

Anyone got a set of S2 complete hubs they want to part with?

An option could be to take the hubs to an engineering shop, bang the studs out and get them trued up