Resonating Brake/s

[John Reavey]

Finally got the 996 upgrade sorted today! On my way home when everything had warmed up there was a loud resonating noise from nearside hub which I could not feel in the steering or through the brake pedal. It sounds like driving along the ribbed line on the motorway with a frequency multiplied by 10 and is very loud! Any ideas what I might have overlooked / stuffed up? When I tip the brake pedal the noise stops but returns immediately after taking my foot off the pedal.

[newsh]

They all do that sir!

When mine does it I take the pads out and copper slip the backs, its been fine for quite a while now.

[s2driveruk]

no they dont John or rather not for ages. definately check they are lubed and also check that the pegs which the pads sit on are well out the way as when the disc expands they can resonate on those too

[s2_wot]

John,
Could it be a knackered (or nearly knackered) bearing? big brakes will beat the last bit of life out of tired bearings very quickly.
Shane

[driftin jo]

backing plate touching the disk ?

[Ross]

I had this recently, backing plate needed levering clear of the disc. I've also had the same noise due to the pins touching the disc when the brakes are up to temp.

[Knight Rider S4]

backing plate touching the disk ?

[Dpicariello]

Welcome to the world of 996 brakes my friend!

Mine do it too, have since the beginning although it's a lot better now. The pins are at least 3mm clear of the disc on mine. I have tried plastilube and copper slip. I've removed the heat shilelds and checked that all the caliper pistons a free.

I was at Lion garage in Hinckley the other week and was advised that a good hammering gets everything quiet again. I must admit that the majority of my S2 time seems to be spent on the motorway at the moment and in this weather, things tend to get a bit crusty.

Take care bedding them in and then make full use of them (when it's safe to do so) and it might just help.

[John Reavey]

Thanks for the input guys, think i'll start with the pins and check the backing plate clearance.

If that doesn't work I'll give them a good thrashing when bedded in a little more.

I'll let you know how I get on over the next week or so!

[Colesy]

There is a thread discussing this here:

http://www.s2forum.com/forum/showthread.php?t=10029

Still haven't got to the bottom of my problems yet...

[Alistair E]

Not sure if I should be posting this here yet but I'll take the chance. The noises from my nearside front brakes have stopped. Well, for three days so far so not counting chickens yet.

Only things done in between having horrendously loud noises and silence were :

Removed wheel
Removed pads
Champhered off outside edge of pad with a file
Refitted everything

It's always been the case that there was no noise with new pads. For this reason i have always assumed that it was the piston travel that was the problem as the pads wore down. Something I noted this time was that the pads had a lip that wasn't being worn down on the outer edge. This is because the pads sit minutely too far out from the hub.
I can only guess that the noise was lip on the pad catching the outer edge of the disc even when the calipers backed off. Very much like the wine glass effect.

Might be worth a look.

When I change discs in the future I'll be looking for slightly bigger diameter discs.

[Alistair E]

Quick update.

Well I'm now a week into a silent car. I've had a couple of minor squeaks but I believe these may be from the offside which I haven't touched yet. Can't believe I've put up with this for nine years. Even had a change of calipers along the way.

Hopfully this may help others with similar problems.

Alistair

[Le S2 Audi]

Question... Did you trim the Guide pins on the caliper?

When I fitted mine I got a new set of Pad dampers (these fit into the pistons on the caliper and are supposed to stop brake squeel) at a cost of over £100.00... Ouch...

But you also need to drive very steady for the first 500 miles, if you have put in the A8 discs, as they are 2mm (I think) thicker than the OEM porsche discs, and with the new pads, they do rub on the disc when you start...

HTH...

[GazzaG60]

never had a single bad noise from my 996 gt2 6 pots on 993 tt discs and ebc red stuff.

no trimming except for a skim off the bottom of pad due to disc/caliper/bracket combo.even ripped off the anti rattle back plates after 2 got loose.

[Alistair E]

I didn't trim the pins but from memory I'm running a narrower disc. I seem to recall they are 314mm x 28mm.

The thing I did notice when inspecting the brakes was that the disc isn't central in the caliper. The gap to the pins is .8mm outer and 2.8mm inner. The pads have worn slightly unevenly and I guess this is the reason why. Need to take 1mm off the inside face of the bell.

I tried to stick the old dampers to the new pads unsuccessfully. The dampers are in there now but not really doing anything