No riding, it’s in the workshop, a new build from old parts.
Brakes haven’t been used for a while, one piston wasn’t retracting so I was cleaning the pistons.
Symptoms of the issue were that with the pads out, I could squeeze the brake lever; the pistons would go in. Release and they’d retract to their original position.
<span style=”font-size: 0.8rem;”>What’s supposed to happen is that when the lever is depressed far enough, fluid should be drawn from the reservoir to the hose and caliper to top them up. The next time the lever is pulled the pistons start from further in, taking up pad wear. </span>
My guess is that the connection from the reservoir is blocked. Anyway after pushing the pistons in and out, and cleaning them, the mechanism came back to life, so whatever was causing the problem is out of the way.
I’d be interested if anyone can suggest how to deal with this should it happen again. Possibly just a change of brake fluid. Or strip the levers down…