I have recently changed my rear rotors and pads as my rear passenger side was somehow eating the rotor away..

What I found out during installing the new pads and stuff was that the caliper piston did not want to be compressed but after messing with the parking brake thing on the caliper, i was able to compress the piston and finish the installation.

I thought everything was fine, until this afternoon. I was washing my wheels and just wanted to see how the rear brakes are doing so I lifted the both sides up and spinned em. The LEFT rear spins freely, without much efforts but the right rear, which I had issues with, had a little bit of resistance compare to the left side.

I have searched and found out that it is Okay for the wheels to have about 30% or so difference in the amount of resistances but how can I measure that without proper tools..

So I decided to look into the parking break status. I disassembled the rear center console to check out the bowden cable assemly and found out that the unit was a bit uneven. (Pictured). My car is parked on an uneven drive way.. but I am not 100% sure of the cause.

Any thoughts guys?

 

so nothing is siezed. But it's uneven. So either one of the cables (most likely) or one of the calipers isn't moving smoothly. Remember the caliper slides as it clamps, so I'd check this too.

If you're up for it, undo the cables and see how they move. Are there any tight bends or anything?

Matt

 

Glad to hear that it isn't parking break. Well, to un-do the cables, I have to disassemble the whole thing on the caliper and on the parking break handle right? Arggggggg I sense a PITA...

O and what do you mean by tight bends?
Thank you Doc!

 

Bravo for a great thread, very detailed, you did your home work, great pics and most of all you paid attention to the details.

Looks like Doc is right on the money too.

I nominate you for thread of the day.

 

https://www.northamericanmotoring.co...d.php?t=137464

The guy in post #9 has/had an ebrake malfunction and a caliper seize that almost appear(ed) unrelated, at least based on the text.

 

hooray

Any more thoughts on how to trace down the thing?
Argg~

 

So first is to make sure the cable works fine. If it does then it's on to the outside of the caliper (cause it's easy... But probably not he problem). First make sure the pads can move freely against the caliper, and that the caliper slides are clean. Then onto the caliper itself. The ebrake lever moves a cam that presses on a shaft. This shaft has threads on it (this is why you need to rotate the piston as you compress it when you change pads, and is the mechanism that compensates for pad wear and still lets the eBrake give enough grab). If it's not the cable, then it's something at the caliper and SOP would be to rebuild the caliper... Here's what sucks... There's no rebuild kit for the rear calliper! (Front either!!!!), so that means you either do the best you can to break things free, do a rebuild and reuse seals, or you get a new caliper.

Matt

 

THIS is what NAM should be like every day

 

I really dislike the arrangement that MINI uses for the e-brake. It is very similar to what Honda uses & here in the land of 4 months of salt & slop they don't last long. Usually it's the calipers e-brake assembly that starts to seize up. Sometimes it can be cleaned & brought back to life. Other times it was replace the caliper. With Honda products there are remans available. Not so with our MINI's.

My SWAG is that your cable is ok. If you caught this early & I think you have, a cleaning & lubing should do the trick.

Good luck....

 

Thank you all for the tips!

Well I forgot to mention that when I changed out the brakes, the outer pad on the PASSENGER REAR has worn to its backing plate while the inner pad had similar amount of padding compared to DRIVER REAR side.

How does that happen normally? Shouldn't the inner pad wear out faster if the piston was seized? I might just pick up a caliper from salvage yard.. but before doing that, I just wanted to know whats causing this issue

 

They should wear more evenly. Was the outer part of the caliper able to move away from the rotor freely when disengaged? You would probably have to unbolt the top and rotate the caliper off of the rotor to see this.

 

How does the rotor look ? Any scoring or uneven wear ?

Had same thing happen to a front brake caliper on a Toyota Celica GTS. The rim got so hot from friction heat transfer from the rotor you could cook an egg on it.......

A long time Toyota Mechanic friend said when they see their calipers seize up like this just takem apart, lube them up (pistons) and put them back together again, I would suggest doing both sides. If you get new caliper(s), fix he old ones and sell them....Nice job btw - great thread !

 

If the inner and outer pads aren't wearing equally, it means your caliper is not sliding to center itself. The piston is pushing the inner pad outward against the rotor, causing the caliper to move toward the car, then when you release the brake pedal, the piston retracts pulling the inner pad away from the rotor. The caliper hangs up, still pushing the outer pad against the rotor, causing high wear. It should slide away from the rotor slightly, but if it doesn't, it is basically 'ratcheting' the caliper inward and holding it there. High wear on the outer pad.
Clean (wire brush) all sliding surfaces on the caliper and caliper mount, and lube with a good high temp caliper lubricant.

 

Sort of related. I went through my first brake change 2 weeks ago. My left rear caliper actually would not retract as I twisted/put pressure on the piston. I tried everything finally resorting to running down to Mini (40 miles away) at 2pm when they close at 3.. plop down 300 bucks and head home. Problem solved. The thing that gets me is everyone can sell the front calipers but only BMW/Mini can sell the rear.

 

Thank you all for some great tips & advises!

So the caliper should move around tad bit when everything is bolted on / off?
I bought a set of wire brush to clean up my coilovers but I will use em to clean the caliper tomorrow and see if anything improves. Oh and I tried to look for a way to pop the piston open but could not find out how to..

I really appreciate the replies! Thanks again!

 

Unless it has changed BMW/Mini replaces the whole caliper as warranties. Like you said no rebuild kits.
However the good news is you can get all the seals at most any auto parts store. The #'s are on the seal and National seals has them. Also may not want to go to far beyond just a good careful cleaning. I had to make one off tools to completely disassemble and assemble the rear caliper to get them powder coated. There is a spider clamp that holds the piston and if the adjuster is extended to far it will pop out having the feeling it is seized. btw
If you need to get another caliper try these guys.

Mazda/Mini Recyclers
http://www.mazdarecycling.com/