I just recently traded a vehicle for a 96 audi a4 2.8 12v. After driving for 30 min I stopped at a store and noticed smoke coming from the front right wheel. After taking the wheel off I found that the caliper piston was not retracting. I've replaced the caliper and the flex hose and bled the full brake system but it is still seizing up and not retracting. Anyone have any idea what it could be?

 

Did you replace the pads and/or rotors?

Is there an excessive amount of pressure on that specific line? Try opening the bleeder valve on that caliper just a little bit, while the car is off and no one has their foot on the brake pedal. If fluid starts shooting out, then you've at least eliminated the caliper, rotor and pads.

A long shot perhaps, but a shot none the less.

GL

 

if you saw smoke and the pads/rotors arent already brand new replace them. there isnt any magic going on. the only other piece besides the particular caliper, is the master cylinder. is the fluid all black and gross? can you confirm fluid is coming out of the remaining calipers? could be a blockage somewhere and thats the caliper that takes the excess pressure. bleed them all. my hunch is a blockage somewhere in the brake system. abs light on?

 

Unscrewing the bleed valve relieves the pressure in the caliper and allows the piston to retract. I've bleed all the brakes and all of them have fluid coming out. I don't know if maybe the rotors and pads got wore down so much that the piston in the caliper is going out too far and getting jammed maybe.

 

Are your pads worn past their wear gaps (the channel cut out of the center of the pad)?

 

I know what you issue is. Check the caliper guide pins ( 2 bolts that hold the caliper in line with the rotor) You can replace the pins (lots of kits) I pulled mine and brushed off a bit of corrosion and applied anti seize. I had the same issue a few years back...passenger right would stick on.....I'd pump the brakes while moving and eventually you could feel it disengage.... after touching up the guide pins I haven't had the issue since...haven't touched the bolts to date either.

 

+1

I just did this to my sisters Camry. I should've said it sooner. Sorry about that. I wasn't sure if it was applicable to our cars.

When you get the seized pin out, make sure you clean and lube the inside of the carrier really well.

Any auto parts store should have a small pack of lube hanging by the register.

GL (mine was a bitch!)

 

I thought so too but their brand new guide pins that came with the caliper. I was thinking that maybe air got into the abs module possibly.