Having difficulty backing off the rear brake piston after changing rear pads- I had other cars that need the piston rotated a little and then it would move back and others have had a screw to loosen so it would back up. Nothing seems to let me push the piston back to allow room for the new pads.
What am I missing???

 

Its a real pain. They do have to be spun and depressed as they go in. Use a plate in front of the spinny tool to put pressure forward onto the caliper. That helped me a lot. Fight with 'em for a little while and they should go. My rears took me 3 hours compared to the fronts taking less than 1.

 

you need a special brake caliper tool to push the piston back in. it's probably about $100. check out the snap-on website

 

No you don't. Check with a local Auto Zone or Advance Auto parts and check their loaner tool program. I used the one from AAP (I work there) and it worked for me just fine. Don't use the adapters though. I used to wheel on the end of the depresser thing right on the piston. That, and you can return it when you're done.

 

A lot of people just use a C-clamp (has to be bigger than 6") or spend $30 and get the tool from Harbor Freight.

I used the tool took me bout half an hour for the rears.

 

With a longish pair of needle nose pliers push and turn the piston clockwise.

Mini does have a special tool for this, we priced it today while at a local dealers garage day. Came out to be about $140. There are other options.

 

Don't forget to take the top off the master cylinder so you can push the piston back in. Taking the top off removes the pressure and should make everything much easier.

 

I have done it both ways, with a 6" C-clamp, the perfect size for a MINI and the Harbor Freight brake piston tool.
When changing pads front or rear what I do, is attach a MightyVac vacuum pump to the bleeder valve and bleed the caliber as I compress the piston. This helps to remove all the crap at the lowest point in the system rather than push it back into the lines. Keep an eye on the master cylinder level after each wheel so it doesn't get to low. Just having the top off will allow moisture from the air into the fluid.
The Harbor Freight tool is great for most all brakes. Got mine on sale for $14.99.

 

I actually used a smaller channel lock to turn the piston while I used a much bigger channel lock to dispress the piston itself- and yes I remembered to open the reservoir! Worked fine once I realized I had to turn it and push at the same time. Can't remember now what other car I had to do that on. On my Miata race car you do it with a small set screw in the back of the caliper- much easier actually.
My wife's car is now back on the ground and the brakes work and the light is OUT!! (EBC green stuff pads.)

 

Harbor Freight $19.95 on sale.

$29.95 http://www.harborfreight.com/cpi/cta...emnumber=40732

 

you guys are killing yourselves. just get a nice set with multiple adapters for all types of cars. that way when your friend with the VW or other car needs to do brakes your not sitting there struggling for 2 hours. work smarter not harder. and i wouldn't leave the top off the resevoir because brake fluid is hydroscopic which means it absorbs air and moisture. in my experience taking the cap off makes no difference.

 

Agreed - I have no problem with buying specialty tools because they always make the job easier/quicker (sometimes a little bit, sometimes a *lot*), and I always end up needing them again in the future.

And while brake fluid does absorb moisture (it's "hygroscopic", not "hydroscopic", BTW), I wouldn't worry about having the reservoir cap off for a few minutes while changing pads or bleeding the brakes - it's not going to absorb a significant amount of moisture in that short amount of time. I definitely wouldn't leave a bottle of brake fluid open on a shelf, though.

 

There are things I will buy at HF and things I won't. This one is about as safe - and as useful a buy - that they have there. Watch for it to go on sale (every couple of weeks!) and pick it up for $20. For the MINI rears it is the cat's pajamas

 

Ok, to be technical you don't have to remove the top, just unscrew it. It's made a difference on every car I've ever worked on. For the 10 minutes you have the top unscrewed you're not going to suck in enough water to make any difference.