CvTech

but they retract just fine.

MikTip

Re: plastic guard??? Last time I checked, they were metal....

SCarGo02

All of my Audis have/have had metal...

lyonelll

-working surface outward, and it was squeeling.

520

- just had to!

ponchojuan66

Front or back brake noise?

Not sure what year of your Audi.

Check that the rotor rotates freely and does not touch the carrier ( rust crap under the rotor).

Check rust did not fall between the piston and shoe, or shoe and caliper.

I'm assuming the shoe slides are cleaned.

I'm assuming you have checked the carrier pins; no binding through the full travel. They can get bent too, but usually that binds them.

If rear, the parking brake didn't hang up on you?

Lastly, any moisture in the DOT4 can cause all sorts of trouble when the caliper warms up. Bleed the caliper. Replace your fluid if its more than three years old.

I had one where a pebble got lodged in the carrier. It was the same color as the metal and I could not see it until I got a big light in there.

Oh yeah, make sure the spring clip on the shoe is there and in correct shape.

It's amazing how many little things can get in the way.

Poncho