So replacing the brakes and found this- back side of a 2015 countryman s all4’s front brakes.

Any idea what this is caused by? Are there more parts then the pads and rotors I need to replace? Factory original breaks as far as I know. No weird behavior or pulling under braking etc, not super low on the pad or anything. only in here because computer said it was time to replace.

Thanks!

 

Front of the rotor is typical wear.

 

Did you look at the piston on the caliper? The inside of the rotor would be the pad that is receiving the piston pressed up against the back of it. The outside pad is pulled against the rotor with the two fingers of the caliper. If the piston is applying even force to the brake pad, then this cant happen. Snap some pics of the caliper piston, dont push it in if you havent already.

 

I actually pushed it in to load up the new pads before I noticed the back of the rotor :/

It seemed to move very easily/freely and there wasn’t anything obviously amiss with it (I’ve done quite a few pad changes in my life) if anything I was surprised how little force it took with the c clamp. Totally dry so I would be surprised if the surface/piston seal was wonky?

 

Did the other side seem more challenging to push back in? Did you remove the master cylinder res cap to make it easier to push back in? I am suspect of the caliper.

 

This type of brake wear is normally the result of sticking slide pins. The piston is pushing on the pad but the pins are holding it back so you get uneven wear. I suggest that you pull the pins and make sure they move freely..

 

This.

Also, rear brake pistons require special tool to retract piston. You have to compress and spin the piston to retract against the parking brake function. If you used a c-clamp on the rear, you may have damaged something.

 

yes- this is the front. I used the appropriate tool for the rear.

Slide pins makes perfect sense- they were moving but I didn’t inspect them closely. I’ll report back later today, check out the piston too.

 

Whenever I do a brake job, whether it looks like they need it or not, I clean up the slider pins and lubricate generously with this stuff:
https://www.napaonline.com/en/p/BK_7651351

Might be a good idea to pick up a tube of that stuff, and add it to your brake procedure. I've never had a slider pin issue since I started using that stuff.

 

The sliding pins makes sense also as a culprit. Also check for buildup on the metal shims. Clean those so the pad wings that go in the metal shims can slide. i use syl glide there too