S4 Brake Help pls.

[docurley]

VAGCOM is a software tool buy RossTec which allows you to tap in to the ECU and read and make changes to different aspect of the car and read error codes and clear them.

Has for the ESP I have never bleeded a car with it on so cant help much there but I would say doing the nipple may help with things but then you would need to bleed the system and make sure the breaks are OK.

Another option would be to clamp off the brake line and undo the brake line from the caliper and then try again but as stated your tool need to turn the caiper piston it's self as it will not push back but wind back.

[innov8]

UPDATE:
I tried disconnecting and re-connecting the battery to release the ABS... No luck. The driver side rear caliper piston still will not retract at all!
I am able to get the piston to rotate in the caliper using a channel-lock plier on the leading edge (being careful not to mar the piston wall) and it rotates with effort but it doesn't seem to be retracting...only rotating. When I then try the special tool, it won't move again...? I am putting all of my weight onto the tool (200ibs), the master cylinder is open and the bleeder valve is wide open. About 2 table spoons of brake fluid has coem out of the caliper...nothing more.

I have contacted the dealer about a new caliper...it will be a couple of days to arrive...not a stock item. I am off work today and would love to try anything you can suggest before I spend the $265 for the new part. Please let me know. Thanks.
Patrick

[innov8]

OK. I got to finally retract! It took an unexpected (and unbeleivable) amount of effort but this is how it happened:
- removed the rotor
- re-assembled the caliper mounting bracket and the caliper so I could hold the caliper still while using two hands on the retraction tool
- opened the bleeder valve and master cylinder
- using was the channel-lock pliers on the end of the retraction tool so that I could be maximum leverage...and my weight.
- this requires patience and endurance!

It all took a while but it eventually went back. Either I am a 200lb wimp or this thing was truely stuck. Has anyone else ever experienced this problem? I assume that I will need to replace the rotors on the next 20k miles as the cylinders are sure to be stuck again.

Anyway, I just test drove the car and all seems to work fine. Thank you for your help and advice. I will continue to rely on this forum and am glad that I have it in my "tool box"

-Patrick

[docurley]

I'm glad you got there in the end as I had run out of ideas.

I was going to say lock of the brake lines and drop the calliper is some sort of penetrating fluid.

I think as the rubber gaiters have gone this allowing for rust to get to the callipers and any period of letting the car stand for a while will cause rust to get to the piston walls and cause you problem.

I'm glad you stuck in there as you saved your self quite a few $$$$'s