I am brand new to Audis. I just picked up my 1997 A4 and absolutely love it. The brakes were shot all the way around so replaced the fronts and started on the rears. Removed the caliper just fine, then went to compress the piston back into the caliper and it will not budge. I have never done rear discs before so I was thinking it has something to do with the emergency brake or something. Anyone have any ideas? Im on the passenger side rear right now, car up in the air!

Thanks in advance.

 

it should compress just like the front ones..

 

You have to compress and turn at the same time.

The hard way:
Some have reported doing it successfully with needle nose pliers but it is a pain and you risk it slipping off and tearing the rubber boot thing around it.

The wasy way:
There is a brake caliper tool you should be able to rent from your local auto parts store. Or buy it from here http://www.harborfreight.com/cpi/cta...emnumber=40732
It makes the job much, much easier.

 

hmm.. i think i actually knew that at some point. but its a good thing i know it again, lol

 

On my 98 A4 I just used some needle-nose pliers and screwed in the caliper.

 

To compress the caliper piston you basically have around three choices.

1. Caliper Piston Compressor Special Tool (do not really need this)[:'(]
2. C-Clamp ( I have used these before-home depot wood clamps)[&o]
3. Large Channel Pliers (use these more than anything else)

I have always used large channel pliers because they give you better leverage. Adjust the pliers as needed to get their handles close enough so you can grip them whileat the same time providing enough room to be able to retract the piston. You want to use the pliers easily and slowly but it may take substantial pressure to push the piston back. Also you want to work the piston uniformly around its perimeter (in other words don't just push on one side of the piston because it could get cocked and not go in evenly), unless of course it goes in straight the first time, sometimes that happens. Remember that it could take substantial pressure to push the piston in, especially if the car has been sitting for sometime. You may have to put pressure and hold it until the piston eventually gives. Also watch out for the plier teethtearing in to any piston rubber seals.....you may want to use something in between the pliers and the piston like a rag or a flat piece of metal or wood.

If you still cannot get it to go in it is possible that the piston is has frozen due to moisture in the system or overheating of the brakes. In that case you may have to bleed the piston to force out some old fluid. Sometimes this helps free it up. If it still remains frozen you probably have to replace or rebuild it.

Sorry for the long post but I hope this helps.

 

The compression tools for the pistons run about $25 at harbor freight tools. They're worth it, trust me.

 

I think it is probably frozen as you said. I have and have always used the compression tool, but this brake just wont budge. Will have to try some more today. Thanks for all the replys everyone!

 

Did you try opening the MC cap and the bleeder screw (on the caliper)?

 

Think that you want to leave you brake fluid resiovoir cap open when you're compressing the pistion, especially if its out really far...might blow a seal on your MC with too much air pressure.