So I was putting on the track pads today to bed them in before I head up to the track tomorrow. I'm now stuck! My piston won't retract at all and it's actually come forward a little and won't go back in enough to even get the street pads back on! I've done my brakes numerous times and while the rears can be tricky this is rediculous!

Anyone have any suggestions? I've been dicking around with this 1 brake (rear right) for 4.5 hours! Nothing I do will get it to go back into the caliper. I'm desperate but don't know what to do. Rear left retracted after struggling for 10 minutes. But rear right?!?!?!

I'd be quite happy getting the rear street pads back on but at this point I'm about to call it a day and put the car into the garage and take it to the dealer on Monday. Towed via MINI roadside or something. There is no way getting the rear pistons to retract should be this difficult. I've got the actual MINI specific tools from a dealer to do this. I've got the little socket with the 4 nubs that can turn the piston but it isn't going in at all and I'm pushing the damn thing as hard as I can and it aint budging. It turns but doesn't retract! I've tried kneedle nose pliars and just about any other tool I can think of. None of it is working and I'm desperate. I really don't want to miss out of this track event tomorrow! I've got a front brake tool that operates much like a C-Clamp and that didn't work either.

Does anyone have any last suggestions?

HEEEEELLLLLLLPPPPP!!!!

ARGHH!

Paul

 

I DID IT! One last try before giving up and it went in. Track pads are on and are about to be bedded. Argh!

Paul

 

There are some threads on this problem-
https://www.northamericanmotoring.co...amp+rear+brake
Consider a big C-clamp or dedicated brake tool.
https://www.northamericanmotoring.co...amp+rear+brake
https://www.northamericanmotoring.co...amp+rear+brake

 

 

LOL, minihune, read my first post I've got the "official" MINI brake tool right from the dealer. It didn't help.

Paul

 

Paul- so what was the trick?

Glad to hear your nightmare ended. wheew! :smile:

 

While changing the brakes on a buddies MINI about a month ago we ran into the same problem. We didnot have the "official" tool nor a 6" C-clamp. What we finally ended up doing was, one of use exercise the e-brake and when released the other would push and turn the rear piston. Repeat process, repeat process, repeat..... You get the picture. It took a while, but we were successful. Earlier, when I did my brakes, I was able to push & turn the piston with just a pair of needle nose plyers. No problems so far. You just have to out think it....

 

No trick, they're just a bi*c*. I was talking to the service manager of my MINI dealer today at a lapping day and he was saying the same thing. They cringe whenever anyone wants to wait for a brake service because of the risk of it taking a long time. Sometimes it goes in easy, sometimes it doesn't.

I did my buddy's car a few weeks ago with neddle nose pliars with no problems.

I wish there was a trick but quite simply you've just got to keep at it until it magically works.

Paul

 

oh I see...thanks for the info. I guess I'll let the experts handle my brakes!

 

Astro Pneumatic (find under mytools.com/astro) has a complete kit which will work perfectly to push and turn the piston back into the caliper. The kit number is 7860, it has 11 pieces to fit different cars. One of them fits the Mini. The kit is usually listed at $48 and is now under $40. There is no need to buy the Mini tool. This is a huge time and money saver if you go through your pads and rotors through hard driving and (in my case) 21 track events in the last three years.

 

Can you check that web site mytools.com just has some software to download. This is what has been holding me back from putting on mintex pads.

Edit- I think I found it elsewhere:
http://www.jackxchange.com/products/7860.cfm

Can you confirm this does has the proper bit? Will I need any other tool?

 

Check Harbor Freight; they also sell a kit and I think it is a bit cheaper.

 

i used a big C clamp on my piston, it worked like a charm, very easy :smile:

 

I think I found the correct link: http://www.mytoolstore.com/astro/asthan12.html

 

yes, it's mytoolstore.com


11 piece kit

 

I just ordered it from jackxchange as they were the cheapest.
I'll order the pads soon, and it will probably take me a while to get myself to do this but now that I know I have the right tools ahead of time I am a little less concerned.

 

I think everyone is missing the point of my post. I HAD THE RIGHT TOOLS! I had the same exact tools that the MINI dealer uses. I've talked to the dealer and sometimes the rear pistons are simply a ***** to get to retract. Right tools or not. Don't be surprised if the pistons retracts fine 10 times and then refuses to budge out of the blue. Dealer tells me they go through this quite often and that there is no "magical fix."

Right tools or not changing your rear brake pads is a gamble every time.

Paul

 

How far gone were your pads? I wonder if it has anything to do with wear?
or maybe something to do with where the piston has rotated to on the internal screw mechanism. I hate debugging problems, too many variables.
did you try loosening the piston before tightening?
perhaps the piston cocked slightly (another wear related question)?
Anyone know the name of the fluid version of vapor-lock? could be some type of back-pressure in the brake lines
just throwing out some logical routes too look along. wonder why the brake engineers never encountered this and why they don't have a rational explanation

 

Pads were 3 weeks old. I was simply installing my track pads the day before a track event. I run seperate street (EBC Green) and track (PFC 97) pads.

Paul

 

Just to let everyone know the Astro 7860 kit I got for $40 from jackxchange worked!

I changed my pads yesterday (finally). The kit comes with several adaptors. The fronts use part #3. The rear doesn't use any adaptor, it fits in. The piston threads are quicker--it goes in quicker than the clamp screws in so after about a half turn it may fall off (just keep some pressure on it), but I only needed one turn anyway.

The only issue I had was the rear pads didn't have a slot for the pad wear sensor. I ziptied it to the suspension, hopefully it is OK there.

 

Just a little insight, since I've had this problem many times (if you did a search for "piston retract" you would find PLENTY of my threads!). I think that the real problem is that the pistons don't always "thread" correctly. They basically screw in like a bottle cap. Only problem is, you can't really feel whether or not the threads line up. I've spent an hour trying to twist in one piston with absolutley no luck at all, and then I give it a 100th try and it magically works as it should have the first time with absolutely no change of technique.

My only thoughts, regardless of tool:

1) Sometimes you can force it, sometimes you can't.

2) Try varying the amount of "inward" pressure you use.

3) Try "starting" the rotation with the piston at different points.

4) Try using multiple methods (C-Clamp, needle nose, channel locks, brake tools)

and most importantly:

5) TRY ROTATING COUNTER-CLOCKWISE!

I've had the best luck when it won't turn in by rotating a quarter or a half-turn counter clockwise and then going back to clockwise. This can make it get in better because (I'm guessing here) it gets sort of cross-threaded, but un-twisting it can often alleviate this problem.

Good luck!

 

I spent tooo many hours on my rear brakes the other night (into early (then late early) morning!) with this problem!

I have the Harbor Freight tool--works like a C clamp, but has a plate with pins to turn the piston.

Both rear pistons were stuck OUT ...I have45K miles and both stock pads were completely GONE on the inside, had some pad left on the outside.

I finally reinstalled the stock rotor and pads, and called the dealer. I HATE taking it there! But I thought maybe my brake calipers/rotor were defective!

Now I'm thinking I'll try again...maybe I have more patience and I've slept now

I'm planning on changing the fluid to redline...which I was going to do after installing the new rotors and pads (EBC greens and drilled/slotted Brembo/Zimmerman set--fronts installed beautifully).

Any chance draining PART of the old fluid (but keeping some in the reservoir to prevent air in lines) would make this easier? Or would it make no difference? I had already opened the bleeder valve to try and remove any excess pressure, (leaked very small amts of fluid) and I had the brake fluid reservoir cap off, under the hood...

Any other suggestions? Thanks for any input--I always figure I'm inept when something I haven't done before doesn't work, and then I find out it happens to lots of folks, and how to fix it. When I get it done, I feel great.
Hope I can fix this without the dealer!

 

Ok, knowing that I was on the right track after reading this thread, I went back and tried the rear pistons again, using the Harbor Freight tool.

I kept remembering..."you can do it a hundred times, and then it will go..."

The method I used was to treat it like a difficult to thread screw....counterclockwise, then clockwise with pressure...

if its not progressing inward, counterclockwise (there wasn't much counterclockwise to go, since I was already most all the way out...)

It worked (with patience) on both brakes, and went in easily enough once I had the piston threaded correctly.
I DIDN"T bleed any brake fluid--didn't need to. Cancelled the dealer appt

Many thanks!