OK new poster- help would be greatly appreciated.

Car is 2001 A6 4.2 with 118,000 miles. I have had it since Jan 2006 since around 50,000 miles. I have KW Variant 2 Coilover system, Hotchkis front and rear swaybars- and a few other minor upgrades.

I consider myself relatively handy for an Audi A6 owner-or at least able to follow instructions to repair/replace in beginner to intermediate level work on my car. I am probably in the "knows enough to be dangerous" category- but I do err on the side of caution as I respect the complexity of the A6. The front pads and rotors were replaced 2-3 years ago and I don't think the rear pads or rotors have been replaced in my ownership of the car. I have never had great response from the brakes which I have always attributed to the weight.

I am in the midst of my first Brake and rotor replacement and have not had too much trouble yet- but am in need of some advice. I did significant research online- both for Audi and non-audi brake and rotor replacement jobs to the point that I was confident I could do this. I purchased replacement rotors and pads for the front and rear, and decided to begin on the rear- as I thought they would be the easier to begin on... I removed the caliper mounting bolts without too much trouble- getting the rust off. I also got the rotors off after some reluctant hard pulling due to the rust. As I said- I am reluctant to do too much as to damage unless I am sure it is the right thing.

I got to the piston retraction- I have the official Brake repair "rental kit" from Advance Auto Parts- which has the correct tools for multiple applications. I used the "rear brake" tool and lined up the 2 slots- began to retract. I maybe got a half to full turn in with hand strength- and then attempted to use 2 wrenches to turn and got maybe another half turn but stopped when it seemed I was needing to exert too much force. I am not a small person and would give myself above average "hand strength" for a 33 year old so if I was having trouble- I started to get the feeling that I might be leaving something out... Since there is nowhere near enough room for the new pads- it needs to go farther.

I then thought I should try the other "passenger side" rear wheel- to see if it was just the first side that had an issue- and got the caliper bolts off- and when I tried to use the tool to retract- it barely budged with hand strength... I also noticed that on the passenger side- the "boot" or rubber cover- maybe on the piston- that was connected to the slotted end- had a small tear in the middle of it. It was there before and I am not sure if this has something to do with it or not.

I do not have the E- brake pulled up at this time and I also took off the "brake fluid" cap prior to beginning as I was told that removing the cap or something on the Brake master cylinder would release pressure to avoid breaking of the seals- which is bad. I also did take my time with the turning- also to avoid breaking the "seal."

I am guessing that releasing the pressure better on the brake master cylinder has to do with this issue- somehow so if anyone has any other questions I will answer-and can post pictures easily if need be. I did take off the Cover behind the firewall- so I can see down below the brake reservoir and can access to disconnect something down there if need be. I have never bled the brakes so i was hoping to avoid that as well but i will do anything to get this going at this point.

So advice on what I should do to proceed would be greatly appreciated as I am pretty much stuck- until I figure this out.

MANY THANKS,
Jim

 

Do you know if the rental kit pushes and turns the piston at the same time? IIRC, you must push and turn the piston in, in order for it to go in. Hope that makes sense.

Also, I think the piston needs to be turned clockwise while being pushed in.

 

It does turn and push at the same time-

it is just very difficult to do so-based on the limited amount of wear my rear pads have- and as I have never had them replaced in 70k- I am wondering how much use they are getting at all...
What is the fluid that is inside the rubber boot- is it necessary for operation- could it be low or out...? Would that impact how easily the piston retracts...? As I said the one side has a tear in that rubber boot and it was super difficult to try to turn and push with the hand crank..

 

Okay here is the answers you are looking for ... your seals are shot your boots are shot and your piston has rust on it and is seizing .. I just did this and can help you out.

It is up to you but I would completely rebuild those calipers.. it is easy but one thing at a time.

You are doing everything right but you need some help. if you have fluid coming from behind the belows on the caliper it is brake fluid. Usually caused by the rust pushing by the seal and damaging it ..

if you just want to get the calipers in do this ....

do one at a time. if you have both calipers hanging make sure you block one of the pistons from coming out with a peice of wood.
.
if the car is on jack stands start the car ( at least i did, you may be able to do it without starting ) . when you can't wind in any more have a partner press the brakes .. don't worry one push will move it about 2 or 3 mm . wind it back in , if it seizes again have your partner push the brakes again .. keep working it in and out and if it is not to serious it will work right back in all the way .... block it back with some wood and go do the other side.. repeat...


Okay that will get your pistons in .. now lets discuss what happened. your boot tore ,got some water inside. and the piston rusted. You need to repair this if you value your brakes. get a line wench and undo the flex line at the body . it is a little difficult as it is slightly under the liner but it will work. take the whole caliper off ... get new flex hoses as they are cheap and are probably original.

conversly you could pump the brakes until the piston pops out .. but if the caliper is off use compressed air to blow out piston.

inspect piston and you may be able to recover it with a wire wheel removing rust but you also may need a new piston.

pull off boot and discard , pull out seal and discard. install new seal in caliper , lube with some clean brake fluid , slide refurbed or replaced piston into caliper with new boot on piston , slip rest of boot over lip in caliper , connect new flex line and bleed brakes.. start from farthest wheel from M/C and move to closest.

BTW bfore removing caliper see if you can crack the bleed niple . if you have to use more than 20lbs torque STOP.. take it to a very experienced mechanic ( the caliper) and have him crack the niples. He will probably use a torch to heat them ( the niples) . If you try it on your own and shear bleed niple you are into new calipers. You probably have ATE calipers in rear ( alluminum) so be carefull.

 

I'm not taking my nipples anywhere new a person that wants to put a torch on them!

sorry couldn't resist.

Good info iceman

 

^^^^ candy *** .. man up and get those nipple out !

 

i just replace by rear break pads on my 2001 a6 with 4.2 and when i did so i used the tool to screw piston back in but man i had a hard time and now i know why like previous post had said there must have been rust on the piston and now its leaking my problem now is i can't find a calliper anywhere only dealer and they want 400 dollars CND so if anyone can point me to anywhere online that i can purchase a rebuild kit or new calliper would b great thank you i looked at hansauto and they didn't have the calliper i needed

 

I have found that partsgeek.com has alot of audi parts at very competitive prices. I found parts here that i couldnt get from dealer websites. Good luck.