I'm hoping someone here can help me out to tell me if I should just change my brakes.
A little background: I've been doing brake jobs on my cars for 30 years. That includes a few years of racing and regular brake bleeds. I've also used and serviced Hope Race X2 brakes with no issues whatsoever. I've had older XT brakes that I never had to touch as well.
But these XTR brakes keep giving me a problem. Online searches result in one of two things: defective brakes (recall by Shimano) or bubbles. I really don't think my problem is bubbles because a good bleed doesn't fix the problem. I have removed the caliper and let it hang under the lever for maximal pressure differential. I've pumped up with a syringe, and down in the traditional way. With the block in place, they feel solid.
Here's the tricky bit:
The thinner my disk or pads get, the worse this problem is. When I switch to one wheel with my thinnest disk, and with maybe 50% worn pads, I get zero brake no matter how many times I pump the lever.
If I put some new pads in, the brakes feel solid. It seems to have to do with maybe longer travel being required in the master cylinder. Pumping the lever results in the pads going in and going back out.
I'm thinking of just grabbing the Hope X2's from my other bike for my race next weekend, but it is bugging me that I can't get these brakes to work well with anything but 75% to 100% new pads.