09-16-2022, 10:26 AM | #1 |
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E84 X1 odd rear brake wear experience
read most of the posts I could find here, so mostly sharing my experience on brake wear. I drive mostly highway, and probably not in a way most would consider "spirited" (ahem...). Never noticed any specific brake performance issues, just that they do grab pretty well without putting a lot of foot into it.
Got my 2014 X1 x28i (no iDrive) CPO in June 2017 @ 31k miles. Seemed very well taken care of, inferring it was driven conservatively. CBM was saying rear brakes due @ 37k, front brakes due @42k. Rears lasted over a year, did them @53k when the wear sensor triggered. Replaced with BMW pads & rotors. Don't remember any odd wear or other observations, only that the rotors were just a tad reluctant to come off the hubs. Ended up clamping an 8 ft 2x4 to the rotor to get enough leverage to wiggle it off. Per the instructions I got from newTIS (before it shut down), I used the BMW brake paste at the pad and bracket contact points, but only cleaned and did not lube the guide pins. Applied new blue Loctite to the bracket bolts and guide pin threads instead of replacing the hardware like BMW would like you to do. Fronts lasted until Oct 2020 and 83k miles, well past the CBM prediction (and my expectations). Also redone with BMW pads & rotors, same process as the rears. Again, no observations that I recall. Now at 100k, just had my rear wear sensor trigger again, and CBM was saying I still had a few thousand miles left (it's a default 50k interval, and maybe one that doesn't vary with conditions), so I didn't take care of it right away. Then I noticed the right rear wheel collecting a ton of brake dust, so I said "yeah I need to take care of that" but didn't. Then the grinding noise started so I got the parts. BMW rotors again, but this time decided to save a little $$ by getting Akebono pads from FCP instead of BMW factory (dealer parts prices have gotten insane since the last time I did brakes). Didn't realize they were ceramic until they arrived, but after reading up on them I'm not too worried about them behaving a little different. Here's the interesting part - check out the pad wear driver's side versus passenger side (where the wear sensor is). Basically nothing left on the passenger side (3/32" on outboard, and inboard just starting to wear through), and 10/32" left on both driver's side pads. There wasn't anything odd I could see about the driver's side bits, no evidence that the caliper wasn't behaving normally, so my only thought is that the ESC or e-diff functions have been leaning pretty heavily on the right rear. But I don't know why they would be - I don't habitually (or ever, really) race out of right-hand turns. Only other thing I can think of is - I had the transmission, transfer case, and rear diff fluids serviced by a reputable indie a little over 2k miles ago. Is it possible that the rear diff service disturbed the torque split so badly that the e-diff chewed through most of the right rear pads in 6 months? |
10-05-2022, 12:49 PM | #2 |
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This is really strange. It almost sounds like the right rear brake is holding up. My rear brakes wore out pretty quick too, and I attributed it to the automatic braking in the rear during cornering, etc.
Did the caliper retract without any issues during the brake job? If it's back together and you're driving it, next time you drive it, take a temperature gun with you, and hit the rear rotors with it as soon as you get home. If the right rear is significantly hotter than the left, well then the caliper must be hanging up on the rotor. |
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10-13-2022, 01:39 PM | #4 | |
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Quote:
Piston retraction felt normal, but the tool has a bit of leverage via the screw thread so not a very sensitive "feel". Given there's some evidence of fluid leakage at the piston boot, seems likely there could be some piston/cylinder corrosion going on, which maybe causes the piston to not retract and hence the brake drags? |
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10-14-2022, 06:17 AM | #5 |
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If you have brake fluid leaking that means the seal on the piston is broken and moisture is getting in and causing corrosion.
You should have replaced that caliper while you were in there or rebuilt it. |
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