Last night I took my calipers apart for a good cleaning. Thank god I didn't spend the 2x$55 for the piston and seal kits. The pistons were in great shape, but very dusty and dirty. The seals looked fine as well. I could feel a fair amount of grit and sediment in the cylinders and fluid ports, which I washed out with brake cleaner/compressed-air/fresh brake fluid.
I've decided that I hate, and am not very good at, dealing with brake fluid! That crap is nasty, and sure has a tendency to get
eveyrwhere.
I'm still astonished at the improvement! They haven't worked this well in years!
I highly recommend getting close and personal with your calipers if you haven't already done so. I'm sure 98% of bikes out there are lacking in brake performance just because of dirty calipers. It took me about 1.5-2hrs from start to finish (30 more min to clean up my mess...
)