Have a problem with Vibration on the back of my car

[BRETTCOLLINS]

Have a problem with Vibration on the back of my car. After changing all the rear brakes. ( Discs, pads and calipers) I still have the problem.

Anyone have any ideas.

[mikeyquattro]

Wheels?

[S4TAN]

Does it only happen under any particular conditions - e.g. hard acceleration? Or is it constant?

[BRETTCOLLINS]

Happens more under braking. and if you apply the hand brake why you are driving you can feel this is coming from the back.

Will swop the the wheels front to back when it stops snowing LOL

[mikeyquattro]

You'll need to dti the discs and hubs to see where the runout is

[buzzard]

could just be a tyre that has gone out of shape .(front to rear swap will show this up)

i had a vibration that felt on the rear....turned out to be propshaft center falling apart ended up having it rebuilt by a prop specialist in our town.

[BRETTCOLLINS]

After I changed the rear brakes from S4 vented to RS4 vented, the vibration even under light braking I worse.

[grizz]

Take a look at the discs for any high spots, were they new or used discs ?? We had the same problem on Scott's car when rs4 rears were fitted , When the discs were skimmed they had a high spot on the inside of one disc .

[BRETTCOLLINS]

The discs were Re-skimmed, But I did have the problem before they were fitted on the old rear brakes.. can't believe both discs have the same problem.

[imolas4uk]

check the hubs for run out,are all the rear bushes ok ?,check the bush at the top of the knuckle

[rolskii]

The discs were Re-skimmed, But I did have the problem before they were fitted on the old rear brakes.. can't believe both discs have the same problem.

Brett .... may sound stoooopid .... but what rear pads are you using ..?

rs2/s4 pads are "deemed" to be ok..... the rs4 pads aren't so tall, the spring+mount are shorter.... not that its gonna make alot of difference but... do the pads pass the inner edge of the disc ...?
do the pads overhang the centre of the floating disc ..? ..... enabling the pad to grab the underside edge of the disc ...?
it happened to mine and its a bastard....

Check the pads are being pulled evenly into the disc both sides, my pads had a wear angle on them showing the calipers are grabbing on the inside more towards the centre of the hub .....
I removed my brakes .... found some less worn carrier guides and fitted them to the top of the carrier pins,
extended all the free play (in bolt holes etc..) away from the centre of hub, tightened it all up and grabbing and crap is all gone .... but I could do with new carriers really.. hth ..

[BRETTCOLLINS]

The pads are original audi pads. the full kit was in excellent condition. I was thinking that it maybe the rear hubs myself. going to get the discs and hubs checked for run off tomorrow. this all started after some hard launching at Santa Pod..

[GardinerG]

Brett, another silly question, but have you checked for play in the bearings? Also, as already said, swap the front/back wheels and see if that makes a difference.

[BRETTCOLLINS]

Yes am thinking Rear hubs or bearings...

[kies4]

I've had an issue with rs6 disks after skimming still vibrated, in the end it was the center of the disk it was warped and didn't sit flush with the hub. Had to get new disks in the end.