Front brake discs uneven wear...
 

My left front disc is smooth, from inner diameter to outer. But, the left is is very uneven, as though the brake pad had diamond chunks or something that wore down the disc with smooth ridges and troughs. A bit concerned now about having to get new discs (they are at 40,000 km's) due to the thinning in the troughs. I have Carbon Lorraine SBK pads. Very odd... Any idea how that could have happened??

Re: Front brake discs uneven wear...
 

In all probability you calipers are sticking on one side and need a dam good service and have needed it for sometime.

You'll find either one of the pistons is stuck or the caliper doesn't slip on the pins properly, a stripe and rebuild should sort in, however it won't undo the damage already done, check the manual for minimum thickness and measure the lowest (thinnest) parts of the disc.

Cheers Mark.

Re: Front brake discs uneven wear...
 

Cheers mark, I did that once already this fall, and didn't pay attention to the discs. Probably needs rebuild again. -Dave

Re: Front brake discs uneven wear...
 

well if you've sort the calipers out ( make sure you "red rubber grease" the seals) and grease the slidding pins, then you'll probably need new pads (as the old ones will be profiled), either change the discs as a pair or get them skimmed if they are thick enough to take it. Then check wear is even after a couple of hundred miles or so, the calipers maybe fine and the disc is just showing past history, it's a judgement call, if you're unsure ask someone you trust to have a look.

Cheers Mark.