Front brakes

[Terry1948]

Adgreen was the VXR8 the first car you had problems with the brakes? I find it hard to believe that your driving style was the only reason you had a problem with the brakes because you had driven a lot of decent cars before that and never had a problem with the discs. What brakes were on the VXR8 out of curisosity surely not brembo. I accept that driving style does affect discs but I also think that the quality of the steel is more important. There are a lot of people who have had problems with their discs on the RS4 and not on any other car that they have owned. Anyway if in a few months I have disc problems I will change my style of driving and it will be proof that the quality of the discs does not matter.

[adsgreen]

Yes vxr8 first problem with brakes but also the first heavyweight (nearly 2 ton) car with monstrous brakes.
Can't remember the brake manufacturer...

Big brakes mean less effort required to slow down. Big multi piston calipers and pads mean large surface area so even less effort to generate light brake loads. The rs4 and vxr8 brakes are IMO well overspec'd for the road which contributes to problem of light braking.

The problem with pointing the finger at the steel is that they would fail under hard use. You could use really thin crappy materiel if all you did was town driving. I haven't tracked the rs4 but I use the brakes hard and they are still perfect over 20k miles later.
The vxr8 also did another 20k miles on the third set of brakes without issue - by this time I had tweaked my driving style.

Finally the floating nature of the discs should prevent warping (or at least help).

[spikeyboy101]

I did read an article from a brake expert that said disc (rotors) dont actually warp - it the uneven build up of brake pad when the material transfers that causes the judder - it just feels like the disc is warped.

The issue is that once this has happened unless you get the discs skimmed the problem just gets worse as the high spots get higher.

This is one of the reason you need to put new pads on when you put new discs on.

What i didnt realise what that the real brake effect doesnt come from friction, but from transfer of material from the pad to the disc when the brakes get hot. when cold it is friction and this is what wears the disc away.


Will see if i can find the article.

[adsgreen]

Don't get me wrong, rotors can warp but with modern rotors this is more likely through overheating or a binding pad.
Just really unlikely through normal road use.

[api330]

new disc for me

[supersi]

did the engineering firm tell you they was warped ? only i could SEE mine was when placed in the lathe and turned.

many guys run pheatons on b5's you can get from any stealer, only really used as a cheap upgrade solution, not drilled but same stock as b7, your need to remove from bells and use your B7

[api330]

They said they where slightly out.

[supersi]

i know its a art to skim them as ive heard what your saying from others, the guy i used was real old skool engineer white haired about 80 ...i removed rotors from bells and gave to him. he tapped the disc true with a hammer first and then skimmed, mine was fine like new for 2k or so (fitted new pads too) ... then dreaded warp came back wasnt pad build up as above but discs

[api330]

Yes I agree I am going to buy some new disc's use old pads as they have loads of meat on them but will use gently to slowly bed the old pads in to start with, Was thinking about the vw ones unless any one knows of any good deals out there (not sure of vw part numbers) can get new oem disc's for £578 all in, Need some asap so if any one can help with vw part numbers or info or no of any good deals pls let me know, Cheers Tim.

[sonny]

Well took disc's of first thing this morning and had them skimmed (at engineering shop) and car is now undrivable with a unbelievable judder so looks like i am buying some new ones, Have heard you can fit the vw pheaton disc.s and they are about half the price of genuine RS4 disc,s does any one have any info on this or should I just Put some genuine disc's on, Cheers

Well thats shocking to hear that they still judder. Wonder if they did a good job?

Im running Phaeton discs at the moment and they seem good. As above you need B7 bells. Heres mine on.

[api330]

They are a lot worse so it was a poor job done with out a doubt, So i would have to use my old bells then and is that ok to do ?, Would you have a part number or the exact model I would need to order them (so i can have a look on ebay at prices) and if your saying your having no problems with yours and they work well then i may buy a set, Thanks for all the info i am getting it really does help, Tim

[api330]

Does any no if this is the correct part number, genuine vw discs, part no: 3d0 615 301 n , Thanks Tim

[spikeyboy101]

Word of caution - if your fitting new disc then fit new pads as well. If you don't chances are you will bugger the new discs as well. Been there myself and found out the expensive way.

[spikeyboy101]

Here you go:

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

[sonny]

They are a lot worse so it was a poor job done with out a doubt, So i would have to use my old bells then and is that ok to do ?, Would you have a part number or the exact model I would need to order them (so i can have a look on ebay at prices) and if your saying your having no problems with yours and they work well then i may buy a set, Thanks for all the info i am getting it really does help, Tim

Cant say what the part number is, I purchased these discs already set up with the bells and engineered grooves in. Many have done the conversion on here including the C5 RS6 crew. Using old bells is fine, make sure all the nuts are done up (not sure if you would need new bolts or not?). As above make sure you use new pads.