Need some suggestions on why I might be seeing uneven rotor wear. I'm a newbie with brakes but I'm learning alot as I go.

The front inward rotors are both seeing uneven wear while the outward side is normal. At every slot there's serious pad buildup all around. I'm guessing the problem stems from rusty caliper piston's not retracting well. One of the caliper pin dustboots was dry and a little squished as well and didn't want to extend.




The other thing I see is the spacing of the rotor within the caliper bracket. It seems a little off center with half the clearance on the inside vs outside. I've only checked one side so far. Is that normal?





And here's the condition of the old calipers for compare.


Thanks everyone

 

looks like you should consider rebuilding those calipers and possibly replacing the pistons

 

I did have one of the pistons out of it's bore and it looked good, no scoring, scratching, etc. (Getting it back in was fun)

Three problems I found. 1) the dried out piston boot seals were stopping the piston from retracting as good as it should. Just lubing with brake fluid and working them back & forth made a difference. 2) one of the caliper pins was rusted on the outer end and a little corroded. I didn't have a spare so I ground off the rust, polished, and lubed it and it spins freely again. 3) all of the boots around the pins were dried out so I lubed them all with WD40 and worked their ranges a bit.

All the calipers now "float" again which wasn't the case when I started. I now realize these parts need annual or bi-annual lubing maintenance"

Soon I'm gonna do a little brake write-up on what to do vs not-to-do. I've got to rework on the rears now as I'm getting some drag there. Upon bedding the fronts this morning I had higher temps showing up on the rears. The right rear got near 550deg before I finished the first cycle.

 

use a small screwdriver and scrape the pad dust out of the slots.. i think that's all the problem on your rotors. once you get that cleaned up, the rest of it should dissappear pretty quick.

the slight difference in spacing on either side of the torque member is no big deal.

 

Not quite that easy Matt. The pad material was fused into the slots. I tried the screwdriver with no success. I then Dremmel'd them out which just proved the rotors were a bit warped. (4yrs 50K miles). Thanks for confirming the spacing. Now that I understand the floating and balance concept it makes sense.

 

man.. well, I'm not surprised if you never clean them out.. I usually scrape/blast the slots on mine clean every few months and don't let the buildup get too thick in there. I think that's all the problems you had. might try scraping them out every couple/few months and see if the pad material is still soft enought o come out that way. I think yours were a combination of pad material and rust fusing together and the buildup was preventing the pads from making good contact on the rotor face..
of course that's all speculation, but a new set of slotted rotors wouldn't hurt at this point.

 

Yeah, stupid me. I wire brushed the outer slots every tire change and forgot there was an inner facing rotor too. I'm sure the alternating Chicago winters and 350ish deg summer braking didn't help things either. I'm halfway done with my newbie repair writeup that's coming...