ok...early this spring I put new brake pads on the front of my car. Then, my timing belt broke so when the car was in the shop we went ahead and put new pads on the rear and new rotors on all four.

Now the brakes squeal like nothing I've ever heard. Different brake pressures = different sounds. When stopping at a stop light/sign I can literally hear four different sounds if I vary the brake pressure. And I couldn't even begin to tell you which wheel the noise is coming from...could very well be coming from all four.

I'm at a loss. Do I need to replace the pads again? Machine rotors? Can the pads be machined to make sure they are flat?

pads are Meyle low dust, no squeal (lol).
rotors came from ECS tuning.

 

Did they apply anti squeak stuff? Also, did you break in the new pad properly?

 

do Audi's have a specific procedure for breaking in the pads?

 

Did you use OEM pads? When I did my front Rotors and Pads I used Hawk HPS pads and followed the bed in instructions that came on the box. I used OEM Audi rotors and had not problems. I do notice that there is a small squeak but I think that is coming from the rear brakes which will be ready for replacement soon.

 

pads were from blauparts.com
rotors were from ecstuning.com

 

Brakes squeel because the pads are vibrating. The fix depends upon why they are vibrating.

I would first make sure they float in the calipers and are not binding.

Next I would remove them and make sure they do not have oil or dirt on the contact surface. If they do try brake cleaner on them - but it probably will not work.

Then I would get some spray on anti squeel - It gets sprayed on the back - not front of the pads.

I suspect the front rotors rusted when you did the timing belt, and the front pads now have iron oxide embedded in them. You'll most likely have to replace them- but it is only a guess.

 

new rotors on all four corners at the same time as the new motor.

 

Check out this article...

http://www.stoptech.com/tech_info/wp_bedinstock.shtml

Stoptech makes high end brake product and has more information on brakes than you care to know.

Also I second what everyone are saying here. Just apply generous amount of anti squeak compound on all parts, including the backs of pads and slider portions.

 

The new front pads were against the old rotors before you put the new rotor on. It sat for awhile when you did the TB so the old rotors might have gotten rusty and transfered crap to the new pads Believe me - I've seen it before.

 

Need to check the calipers are free floating, the anti-squeal pads were installed (or use the spray/paste), the rotors are clean, the rotors are the correct thickness....etc.Depending on year, there are 'anti-rattle' springs that need to be installed too...