|Posted on Monday, August 24, 2020 - 11:48 am: ||
new to me 09 uly. sat a long time, when i rode it home from transporter rear MC locked up. got the last couple of blocks home with the brake on.
Ive now put a used MC and a new old stock MC on it, bled it forward and backward and with a vaccuum machine. had it apart, caliper moves when you step on pedal, delglazed the brake pads, yet it still wont stop.
Has an aftermarket brake lever, I almost wonder if if doesnt have enough swing to actually push the MC to capacity (factory type on order)
Any other suggestions how to get the rear brakes to work?
|Posted on Monday, August 24, 2020 - 04:35 pm: ||
Vacuum bleeders are a pain. They will suck the caliper/piston all the way in. Try pumping the caliper piston out. Full bleeder tube to jar with brake fluid. Bleeder closed, push down lever. Piston will move out a little. Lever still down, open bleeder. Release lever. Bleeder closed, push lever, hold down, open bleeder, lever up. Repeat until piston/pad is touching break rotor. Small volume mc wont completely fill up caliper and piston on one pump. I went to a 11mm brembo mc (.433" vs stock .5"). Gave a little more brake feel, and still stops great.
(Message edited by Kickerdrb on August 25, 2020)
|Posted on Monday, August 24, 2020 - 09:49 pm: ||
See how the brake line goes uphill from the master cylinder and then down to the brake caliper? That arch can be pretty full of air. Brake fluid will pass back and forth all day, but the air space trapped in the hose will damp any pressure that you try to develop. Left in place, there is no bleeding method that will clear that much air. Demount the rear brake caliper, unclip the hose to allow you to raise the caliper so that the brake line is pretty continuously uphill from the MC to the caliper. Try not to raise the caliper higher than the fluid reservoir. Press the piston fully home so that the caliper empties its fluid into the reservoir and now, keeping the caliper raised, bleed as normal. The air in the brake line should be expelled pretty quickly. A block of wood between the piston and caliper makes the task a bit less tricky.
|Posted on Tuesday, August 25, 2020 - 09:22 am: ||
Thanks guys, both good ideas. Ill give them a shot