RS4 BRAKE JUDDER

[pDkALO]

Interesting Tim - look forward to seeing the pics

I had my current discs skimmed + pads done late last year, and the results were absolutely stunning! unfortunately about 3 months later the dreaded judder started coming back (nothing changed on the car), which rules out the hubs or wheels - sometimes it's minor, sometimes less so, but always irritating

I've got a theory about the cause that I'm going to test out in the next month or so with some tweaks, and will keep tabs on how I get on

[Timster]

Images show the groove cut by disk-lip, through the cable sheath and into copper conductors.

My theory being that the lip spinning within this groove "could?" be the cause of vibration.

Apologies for image size... click to see full resolution.

The pad surfaces themselves are actually in pretty good shape with little/no crumble and zero scouring.
(sonny, look and learn )

[DuncS3]

I also used Marcus on my M3 after a track day left severe judder - he came to my house and sorted - easy and he did a great job - just thought I would add to the thread as he deserves the good press.

[guy]

Just had a look at the web site and I see he does a postal service too! That may be the route I take if I can't find anyone with a good rep up here in Aberdeen

[surfpunkian]

Maybe a few Scottish based jobs splitting the travel cost would tempt Marcus up? If certainly be interested if he stopped in Edinburgh on the way up!

[Robnic]

A decent independent garage will have a Pro-Cut disk brake lathe machine, a lot of main dealers have them to but only because it is on the approved tool list and a must have. Pro-Cut have a dealer locater see http://www.skimmydiscs.co.uk/ not saying all will make as thorough a job as Marcus but they should do! so if he won't travel to you up north see who has a machine local to you and quiz them

hth

Rob

[brn7y]

Only a few of them have the special modified tooling to do our floating front discs.

[Robnic]

There isn't a modified tool but they do need to have the later larger machine to handle the diameter and an additional spacer, no probs with floaters

That's why I said quiz em

[DaveB1970]

So we've got all sorts of proposals for preventing vibration from turning the rear brakes off through to skimming a floating rotor.....

A lathe will cut square to X/Y if it IS possible to skim the discs then its probably due to the fact that the mechanism on the rotors - thats to say the bobbins and the slide plates upon which they float are siezed solid. They are designed with float - you CANT skim a floating disc, its a disassemble job and preferably get them ground or mount the rotors alone on a square dolly and have them skimmed that way.

Pad transfer is prevented by following the bedding procedure TO THE LETTER....

Road pads are cold pressed - this means you the driver finish the manufacturing process in service, by introducing heat on install you in essence cook off the working surface making them serviceable if you don't and you get to the "raw" (wrong word but) "Squishy" middle bit of the pad then it will transfer. You can drive through hot pad transfer but cold transfer caused by a high spot on the rotor will need a DA and some fine sandpaper to shift

The only way to prevent it is buy decent pads and not the Ferodo DS2500 lookeylikey pads that are OEM, I think they are supplying Pagid now which is an improvement but still reg90.

The other thing to do is service the callipers at least every two years, if the pad isnt lifting off the rotor then you may get cold transfer on every pass a hundred thousand times or so on a short commute, it builds up and when you get them hot hey presto vibration.

A gasket set from TPS is about £120 a corner you just need to treat it as a cost of doing business every two to three years

[Firestarter]

Guys
Can I just say thanks for this thread. I've spent the last hour reading every post and its give me a fantastic overview and also understanding of the brakes on the RS4. When I test drove the RS4 on Tuesday (I am collecting on Aug 15th) there wasn't any sign of brake judder, however this thread has allows me to understand that it could occur and if it does there is a fix in place using Marcus. Its also confirmed that I will not be taking my car to Audi for servicing after reading some of the horror stories a few members have been through

Thanks again guys great info and advice

[Marten]

My brake judder completly went away after 2 hour track day. I was very supprised!

[johnnydog]

I think it would wrong to 'tar' all Audi dealerships 'with the same brush'..... the inference from some of these posts that all Audi garages should be avoided gives the wrong message. All dealerships vary - Epsom Audi where I got my car (in 2009) were terrible in all aspects (it's a long tale), but Preston Audi who have serviced it during my ownership have been excellent, especially with my brake issues. Generally, dealers get highlighted for their poor points, with good dealers not being mentioned as much as they perhaps should be. I believe there has been a previous thread on 'good' dealerships - I wouldn't dismiss them without possibly researching your local Audi garages for views of forum members who have used them!

[coffey555]

Interesting reading:

http://www.stoptech.com/technical-suppo ... ther-myths

[PetrolDave]

I think it would wrong to 'tar' all Audi dealerships 'with the same brush'

+1

There are some terrible dealerships who have close to zero product knowledge, but there are some that really employ good technicians - you just need to ask around and you'll soon be able to sort the good from the bad (and the truly terrible).

[adsgreen]

They are designed with float - you CANT skim a floating disc, its a disassemble job and preferably get them ground or mount the rotors alone on a square dolly and have them skimmed that way.

I would normally agree... but if you are used to true floating discs then the rs4 ones are a bit of a curveball. I unofficially refer to them as "semi floating" as the spring type fittings in the bell housing are quite strong. The disc is forced on to the edge and whilst it can move and expand it certainly doesn't float (or clatter) like a superbike disc.
I would suspect that if you are very careful and took lots of time then you could skim them perfectly fine.