Severe wheel wobble under braking!!

[SpeedJunky]

Guys,
When I am doing a fair rate of knotts and I touch the brakes I am getting severe wobble on the steering wheel. Its getting quite worrying now as its the worst I have had in any car ever. This is saying something as my other cars were pretty damn bad!

Now I am guessing this is glazing of the discs, as one other symptom is when I lightly brake approaching lights, the car slows at different rates as the wheels rotate if you get my meaning?

I bought the car just before xmas, and when I took it for a test drive it seemed fine with no wobble. Also trust me when I say I dont think I am driving/braking in the car that hard but it seems to be getting worse.

Am I on the right lines? It couldn't be a dodgy wheel could it?

Also, if I am assuming correctly, then I will need to replace the front Discs and Pads. Now if they are this crap I dont want to invest in standard B5 discs/pads again. NOw I know there is a sticky about B7 discs on a B5, but when I made enquiries I was being asked for over £2000 for the "kit". Is this the going price? Where can I get em from at decent price?

Thanks,
SpeedJunky

[dace]

Looks like a warped disc to me. You can get the B7 set up for much less than 2k

[Emp2k]

Have the same on mine but only when i brake lightly from highspeeds as 170km/h and upwards. If i just drive around in town it dosent happen.
I know i have all 4 wheels slightly bent and one rear wheel so you can see it clearly (I know new are on order and should arrive in 2 weeks time.) tireshop tells me its ok to drive around on but still. Im pondering if this could be the cause for the brake problem? Seems kinda stupid to fork out för new discs and then still have the problem.

[SpeedJunky]

Can someone tell me where I can get calipers/discs/pads for less than £2k please?

Emp2k, thanks for you response, am I being alittle niaive here, but I have just been out to measure my wheels, measuring with a tape measure horizontally and vertically to see if there is any difference, they all measure lip to lip 19.5 inch give or take the odd MM, but that could be my measuring giving the margin of error. Or am I missing something on how these wheels deform? I guess I am assuming the wheels go oval?

[Emp2k]

Mine are oval yes.
What if you raise the wheel and spin it? You should be able to see if it is oval if you get it to rotate at a descent speed?

[Nige_RS4]

Mine are oval yes.
What if you raise the wheel and spin it? You should be able to see if it is oval if you get it to rotate at a descent speed?

The soft RS4 wheen normally bend on the inner rim, so look at this.

Have you tried heating your discs and pads up to remove any deposits on the discs - some hard braking from sensible speeds with cooling down in between can often remove deposits. IMHO discs don't warp that often on modern cars.

[SpeedJunky]

Thanks guys,

Ok I will check the wheels on the inside and rotate the wheels, prob have to do it on the weekend.

Nige, I am not a believer in warping as such either, I have read a lot of articles that say there is no such thing (pretty much) and that it is glazing of the discs on sections of the discs so you have different coefficients of friction on different sections of the disc causing the steering wobble.

In answer to your question, yes I stamped on the brakes from about 90mph quite a few times yesterday as it happens, it seemed to calm the wobble down at the time, BUT, when I got back in the car to go home the braking/steering wobble was miles worse....really really bad.

[rsmonkey918]

May be nothing to worry about, I've got the B7 setup already for 2 years now and I get the same thing if I just brush the brakes- probably because the pads have been knocked back during high speed cruising- if I tap them slightly and then apply them hard there is no wobble at all, or the next time I apply light braking force. Also, if your car tramlines the effect is going to be similar as the wheel tracks the groove in the road knocking the pads in, and because there are six either side they're probably going to pop out at different rates with light pedal pressure.
Have not noticed any deterioration in performance when I use the brakes as God intended....

[SpeedJunky]

UPDATE:
As a starting point I went to ATS to check the balance on the front wheels. I was informed that 2 out of my 4 wheels are badly buckled (great!). Oh and plus they faulted every tyre so I need 4 new tyres (when it rains it pours!!).

Anyway, as luck had it I went to a local wheel refurbishment place, the guy there was well aware of the Audi RS4 wheel curse, he had some RS4 wheels on the floor ready to go, but as it happens I didn't need em, they have sorted the 50p look of one of my front wheels (he will do the rest tomorrow). I get my tyres tomorrow too.

Driving back, the wobble on the braking seemed a lot better, so if all wheels are done....fingers crossed.

I need to get the wheels/tyres sorted tomorrow, if the brake/wobble issue still does not go away then it must be the brakes.

[Emp2k]

Sweeet hope this cures it for you.
Will se if the same happens to me when i get my new wheels to.

[TinTin1201]

Hmmm,i also woud say warped disc's or bukled wheels..... I had a similar prob on my previous MTM S3,i changed the pads & disc's... prob gone

[SpeedJunky]

Emp2k, yeah fingers crossed for you! did I read right somewhere? £2500 for a new set of wheels?

Thanks TinTin, it could be both for me yet....I hope not like, but it could be.....

[TinTin1201]

Speedjunky.................. if your after new/or used wheels ,but don't want to pay a 'stealers' price, try ebay or Pistonheads.
before you part with some hardearned cash try & get to look the wheels over (& the person selling them !)

I bought some excellent 19"refurbed original B7 Rs4 alloys for a great price on Pistonheads awhile back(you've got to be quick to strike a deal ,mind!),might be worth a vist

[RS4KILLA]

have a b7 front brake set up for sale in the classified section £850
front calipers
front discs
front pads
bolt stright on to the b5 rs4

[SpeedJunky]

Sorry guys, I must have missed your posts. I would have been tempted by the B7 brakes, but I now have on order the KSport 356mm 8-pot Brake kit which should arrive in a couple of weeks. I ended up being a little disolusioned as i could not seem to find any B7 kit....for a fair price...or so I thought until I saw your post RS4KILLA.

Not to worry, the KSPort stuff cost me about £1000 including Yellowstuff pads which aint bad.

Cheers
Junnky