a4 brakes squeeking and juddering ?

[plumo]

hi just got my audi a4 and there is a funny problem with it first of all the brakes are squeeking from the front ??
but the pads are like new ??

secondly when i brake hard the brakes tend to judder and make a wierd noise and the brakes dont seem good at all when braking hard ??

[sbt]

hi mate i am presuming you have just bought this car if so the first thing i would do is strip the front brakes down and make sure there is some copperslip grease on the back of the pads also make sure the anti rattle springs are fitted at the same time you can check the condition of the brake discs make sure they have even wear and they are not overly worn by checking the lip on the outer edge. i have known of circumstances where a person selling a car replaces pads because the pad warning light as come on some people not all are none to bothered about the quality of there work as long as the light goes out and the car is sold hope this helps

[bp083503]

Yeah i would second that, also if you do not have any copper slip on the caliper slides the pads will stick. This may have also caused you pads to stay on slightly all the time and might have caused your discs to overheat and warp, this would usually explain any juddering or rumbling (especially since you say the pads are new). I would whip off a wheel and spin the disc around watching closely the gap between the disc and pad as you do it, if there is no gap then suddenly a gap they are warped.
I am unsure the prices of discs and pads at the moment as i am new to the A4,s, if they are cheap and yours look half worn get some new ones, if they look quite new and they cost a bomb you can consider getting them refaced at a local engineers, might cost you 20quid. The beauty of doing this is that they will never warp again as they have already heat treated themselves. (back in the old rally days that's what they did, put new discs on, warp them, take them off reface them then put them back on ready for an event).

With regards to the squeaking that is often a sign of excessive brake dust vibrating around the caliper (another sign of dry caliper slides).

I dont know how much truth there is in this but i did once read that if you have breaks on a VAG car that squeak get them sorted as soon as you can afford as it is a sign of a problem. Last thing you want to do is leave it and leave it and damage a caliper. (I craked a caliper on the back of my Audi coupe because the brake overheated due to sticky pads.

Sorry for the essay

[sbt]

hi mate new front discs each ate £24.95 eicher 21.95 personally i would choose ate all plus vat and to be honest you should always fit new brake pads when fitting new discs front pads cost eicher 24.95 and ate 34.95 again i would choose ate and again plus the dreaded vat and before you put copperslip on the sliders give them a dam good scrubing with a wire brush forgot to mention all from euro car parts

[spartacus 68]

I would whip off a wheel and spin the disc around watching closely the gap between the disc and pad as you do it, if there is no gap then suddenly a gap they are warped.

In my opinion it's unlikely they are warped. What tends to happen is pad transfer onto the disc. This could be due to a sticky caliper piston which doesn't retract after braking - effectively leaving the pad in direct contact with the disc - trasferring pad material to the disc surface. You'll feel this as vibration through the brake pedal.

Look at the disc - if there is any evidence of scoring, or heat spots (will show up as blue marks), then replace the discs and pads. Ultimately the caliper will need to be overhauled or replaced - or this whole scenario will happen again. Check the rubber dust sleeve on the caliper that it isn't torn - leading to corrosion on the biston bore surface - causing it to stick.

If you do overhaul - replace the rubber 'o' ring inside the caliper.

My brake choice would be for vented Zimmermann discs and Pagid pads. Best combination I've tried to date.

[plumo]

thanks for advice guys

[darkhorse1001]

not wanting to hijack this thread, but maybe take it off at a slight tangent.

for years i have always stuck to the rules and used a small dose of copper slip on the back of the brake pads whenever i have fitted them, or to help cure a squeal. that is until i bought a set from audi and found they have sticky pads on the back of them. this would seem to achieve an effect completely the opposite to what i had presumed copper slip would do.

whats the deal?

[sbt]

hi sticky pads or copperslip should acheive the same outcome its still a none metalic buffer between two peices of metal it just prevents any high speed vibration which is basicaly what a squeal is

[darkhorse1001]

ah, ok.

i always thought the copper slip was to allow the pads to move a little laterally while under load hence the confusion over the sticky pads which would seem to hinder this if anything.

cheers for clearing that up.

[lucianus]

hi. i have the same problems and i was wondering how hard is it to change the brake pads? do i need a ramp or any other special tool? oh and where can i buy that copper slip? thanx alot