Brake Disc Scoring

Robert Eilers · Post by **Robert Eilers** » Sun Jan 06, 2008 11:19 pm

The brake disc on my left wheel is beginning to score - groove around disc. I replaced the pucs on both wheels about a year ago. I replaced the right disc with a new one and kept the left disc. The scoring is a recent development. I have the single puc Clevelands. I researched previous forums and even took a look at the Cleveland maintenance manual (trouble shooting). I don't find anything that specifically identifies what is the cause of grooving. My intuition suggests a cracked puc.

bradbrady · Post by **bradbrady** » Mon Jan 07, 2008 12:47 am

or an incoreclty set rivit.....you should dissamble and check.
brad

Robert Eilers · Post by **Robert Eilers** » Mon Jan 07, 2008 1:57 am

I pulled the wheel this afternoon and inspected the pucs. Pucs were in relatively good shape, no cracks. I did notice that the puc on the tire side was a little loose. I tried applying additional pressure to the rivets with the rivet tool, but the holes seem to be just a little larger than the rivet shaft. I used the rivets that came with the replacement pucs. The fix might be to use oversized rivets.

I also discovered the left brake drags a bit. If I collapse the hydraulic plunger while the wheel is off the brake does not drag - until I apply the brake and then the brake drags again

hilltop170 · Post by **hilltop170** » Mon Jan 07, 2008 3:39 am

If I recollect correctly how the Cleveland disk brakes work, the rebound of the piston o-ring when brake pressure is relaxed is the only force available to retract the piston/puck away from the disk. If the o-rings are old and stiff, they loose resiliency and do not rebound as much. Replacing the o-rings might help keep the brakes from dragging.

HA · Post by HA » Mon Jan 07, 2008 2:57 pm

what Richard says. often the calipers get gunked up, or the o-rings on the pistons get stiff with age, and then the brakes drag. You might need to disassemble the calipers and clean things up, sometimes the outer ends of the wells where the pistons ride get corroded or scored up too. you can clean those up with some scotchbrite (LIGHTLY) and things will work better upon reassembly.

the scoring on the discs is pretty normal, either a rivet dragging if one of the pads is worn down or dirt that got in there.