The brake pad wear sensor recently lit up on my 2004 MCS. All the pads look fine except the right rear (where the rear sensor is) -- it is far more worn than the other three corners. Reading the forums here, it looks like I probably have a dragging caliper.

I am always inclined to rebuild rather than replace, as much because I like to see how things work as anything. Rebuild kits are available for the fronts from MiniMainia, but I only see dust boots for the rears. I assume that this is not enough to rebuild the rears. Does anyone know where I might get a rear rebuild kit? If not, I would welcome thoughts on sourcing for an OEM equivalent replacement caliper.

Thanks,

Tim

 

Be careful when determining if a caliper needs rebuilding on a MINI from wear only....if you do aggressive turns in one direction a lot, the corner braking might be more active on that corner, leading to uneven wear...You might be right....try to use the caliper retracting tool (many have bought one from Harbor Freight cheap) that twist and push in at the same time (needed on the rears only...warning, some brands of tools will not come with a puck/pusher thingy small enough for a mini)...and see if it rotates in goes in....if it is stuck...then you have your answer..

One reminder to all...MINI recommends a brake flush every 2 years since DOT 4 fluid has more moisture problems than the previously more common DOT3.....Keeping the fluid clean and dry will help prevent the seals from getting gummy, leaking, and keep brake performance good, preventing "fade" in some situations.

 

The caliper slides could be dirty & gummed up. That will also cause uneven brake wear. Check all of the easy things first before pulling the caliper apart for a rebuild.

Zippy is correct old fluid boils at a lower temp due to moisture absorption plus that same moisture can cause corrosion. You haven't lived until you've boiled the fluid.

 

What is the best approach to diagnosing and dealing with "dirty and gummed up" caliper slides? If it rotates and goes in using the tool (currently on sale for $20 at harbor freight -- on order) does that really mean that it does not need a rebuild? Would I just extend the piston and wipe it down well with solvent? Sorry for cluelessness -- I have replaced the calipers on my '81 Fiat Spider 2000 -- but never rehabbed a modern caliper.

 

The caliper slides are the part that the caliper mounts to the car on. There is a bracket that the pins go in & slide on. My best guess is that may be the problem.

Read this... https://www.northamericanmotoring.co...beginners.html

The Allen bolts are the slides.

 

As long as the Seals are good...and it is not leaking fluid, you should be able to clean it up, and re-install it. What can happen if they have gone a long time without a bleed/or was very dirty is the "pucks" sieze, or the inside of the boars (Cylindar walls) corrode, and are no longer smooth..so if you try to rebuild it, it just tears apart the o-rings/seals on the pucks that push out the pads. If you calipers are moving, and not leaking, you should be fine. NAPA are now carrying some MINI parts...they may have re-manufactured calipers available for less than what MINI sells them IF you need them. Should be a 1 day order item in most places.

 

Another possibility https://www.northamericanmotoring.co...rake-drag.html

 

Great stuff! With guides like these, I ought to be able to get this sorted without much suffering at all. Well, I guess there is always a bit of suffering. I'll report back -- probably Sunday. Thanks again.

 

I replaced the rotors and pads (drilled rotors, EBC Greenstuff pads) and found that the right rear caliper slides did, indeed, have crud on them. I cleaned them, reinstalled, and declared victory.

Now I realize that it is dragging again -- but the slides are still clean. The ebrake looks to be okay. This is not a huge amount of drag, but enough that you can definitely feel it when you spin the wheel by hand. With the wheel off, I can still turn the rotor by hand, but it won't spin freely.

It is kind of hard to get the caliper to retract with the Harbor Freight tool -- but not extremely hard. From what I read, this is not unusual. I don't see any signs of leaking.

The question now is whether I replace the caliper ($345), replace the caliper guide bushings ($60), or do something else. Any thoughts?

 

Did you grease the slides, or just clean them? I'd grease them w/high temp brake grease. You can also replace them with TyrolSport bushings (but those require a bit of maintenance.
Does the other rear spin more freely?

 

The rears don't spin freely on mine or the several other MINI's that I've touched the brakes on. If you can turn them by hand without using a lot of force I'd say they are OK. Pads will always drag somewhat, front & rear.

At this point I'd say keep an eye on them & don't spend your money at this time.

 

I hate to bring up an old thread but now that the temp is in the 20s I noticed my parking brake does not release all the way in the morning. If I drive for a mile or so it releases and then I don't have problems all day. I noticed one rotor is clean and shiny where the other has rows of rust... Like the caliper is not seated completely on the rotor or not clamping at all. Any thoughts?

 

I saw a set of rear calipers on sale at LKQ on ebay.
Price was very reasonable.
Did not see if you changed fluid or not.
That can really make a difference.

 

My fluid has been changes religiously by me, last changed a year ago.

 

My first thought would be to pull the wheel and caliper (on the rusty rotor wheel) and make sure the sliders are lubed, and then check the piston - are you familiar with the 'push and turn' operation? The piston/pad interface is also odd, not sure if the clip coming off would produce that type of wear.

 

Thank,yes I have done the brakes a couple of times. We are on our second rotors and pads on both our minis. My wife's mini is not having issues and we have the same equipment.

I need to get the wheels off to look at the calipers, just too darn cold.

 

I know this is an old thread, but was this ever resolved? I'm in the same boat, but I found the left rear caliper boot is torn Mini says there is no OEM caliper rebuild kit I can buy, and parts for these cars are not plentiful at the mass market auto parts stores (kragen/schucks/checker/orielly/napa/autozone).

I found a rebuild kit online at auto parts warehouse I think I'm going to buy, otherwise I've found aftermarket calipers for like $180 each (painted).

 

I bought a BMW/MINI rebuild kit for my R53, but it only comes with the boot, not the inner seal.

Here's a schematic:

http://realoem.com/bmw/showparts.do?...35&hg=34&fg=10

What did you wind up doing?

I'm wondering if it's a good idea to pop the piston all the way out without a replacement inner seal. Has anyone successfully rebuilt a rear caliper? I guess you can't truly rebuild it without replacing the inner seal, but can you take the piston out and reassemble it without messing it up?

-Eric

 

This is an old thread - hope someone is still following that can guide me here. I recently replace the rear pads & rotors on my 2006 MCS. I did not realize the caliper pistons were the 'push & turn' types - I just 'pushed' them. The right one was much more difficult to push than the left. I assume this is because of the parking brake? So did I ***** up this caliper by pushing and not turning it? I've only driven it about 500 miles since the brake job - all is going well EXCEPT the right rear is making a "ticking" noise while driving. And it gets louder when I brake.

Do I need to replace the caliper? And if so, is there anything tricky about it? I've searched for a YouTube video on how to do it but had no luck. I've replace calipers on my Ford truck before but never on the Mini.

Thanks in advance for the feedback!