problem with new brake discs

[bendy1]

Newbie here - hope someone might be able to offer me some advice!

Just replaced front discs and pads on my A4 (51 reg Avant 2.0) and have quite noticeable brake judder - can feel pedal pulsing under even braking gently from low speed (haven't bothered to try from high speed as yet).
I've taken the discs off again twice just to make sure i cleaned up the hub flange and back of disc perfectly, this may have made a very minor improvement if any. I have not used any copper grease or similar between the hub and disc on reassembly to make sure its flat. I also tighten the wheel nuts up gradually by hand with (inaccurate) torque wrench (in this 'order' - 1 - 3 - 5 - 2 - 4).
I dont have a dial-out gauge to check, but i can only assume it's a warped disc. I was going to go back to place i bought them, buy another disc then swap this in turn for existing ones to see if it identifies a rogue one. Before i do is there anything else i should try or any other suggestions?

Also, i must admit i've never like the sandwich style (i.e. only retained by wheels) method of holding discs on!

thanks
Ben

[Marco34]

I was going to suggest the rust build up on the hub, but as you've checked that's ruled out. Sounds to me like a buckled disc. Seems odd though. It must be hard to manufacture a buckled disc. I had problems when I did mine in that the temperature of one disc was hotter!! Tried all sorts. no difference. In the end had two new calipers. Tried new discs, just the same. By this time it was at a brake specialist. Swapped my original EBC discs back all ok!!! :confused:

With yours I'd take them back. I know it's a pain in the *** but you need it sorting.

[John140]

No question about it, one of the new discs was either distorted from new or warped the first time it got hot. Assuming - as you say that you have thoroughly cleaned the mating surfaces between disc and hub, I would take the discs back to where you bought them from.

[churp]

you can get these thin metal clips like what manufacturers put on cars when new which hold the disc in place without the wheel.
These only work if stubs are in hub and the disc fits over the wheel studs. must have wheel nuts not studs, dont no what have on a4's cos have never taken the wheels off of mine

[bendy1]

thanks all, doing as suggested and taking them back - local motor factors are as good as gold (and were cheaper than i can buy anywhere on line for the parts) - said they'd exchange both of them either as a swap or bring back old ones later.


unfortunately A4's have bolts rather than nuts on studs, although you can use a wheel bolt with a nut or spacer to hold the disc on temporarily in leiu of a clip!

[stua4]

Similar to my other response, so posted here too...

'Hi,
I have had a similar problem. I put some new front discs and pads on about 3 months ago and after a week or too they started squeaking gradually. I re-seated them with even more cs but it didn't make much improvement. They started to shudder too and apparantly lower quality pads can warp easily when hot and it could be the problem. I have just ordered new (higher quality) discs and pads all round from GSF for a total of about £180.

Hopefully this will sort my problem!'

Will let people know.