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Front brake
- Thread starter crybinsk
- Start date
And the cap sits on top of the spring like this right?
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it's like motor oil threads but I'm in the brake fluid as assembly lube camp.
Don't answer that. I see it thanks
I don't have piece that sits over the rubber boot. And when the cylinder comes for the caliper what would you use for that?
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No biggy on that ring. The boot will stay put. I like Valvoline 3-4 synthetic brake fluid. Works in about 95% of brake systems and it's my assembly lube too. Seems to not hurt paint much either.
This ok?
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It's DOT 3, so yes, it'll work.
Ok I'm.list again. I cleaned the master cylinder and the caliper followed the instructions perfectly (I think) filled the cylinder an started pumping the brake. It never really got stiff. I kept opening and closing the bleeder as in 4 pumps with bleeder closed. While keeping the brake squeezed I closed the bleeder. I have fluid coming into the bleeder tube but it's not activating the cylinder? Am I missing something?
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They can be a real pain on these bikes.
Easiest way I know is to take the caliper loose from it's mount so you can lay it on it's side.
Remove the piston and fill the caliper with fluid, then reinstall the piston.
Rotate it upright so any air floats to the top (the hose banjo) and slowly push the piston back in.
Watch the reservoir don't overfill itself.
What you're effectively doing is pressure bleeding using the caliper to force the air out the top. Sounds a bit flaky... but it works.
Easiest way I know is to take the caliper loose from it's mount so you can lay it on it's side.
Remove the piston and fill the caliper with fluid, then reinstall the piston.
Rotate it upright so any air floats to the top (the hose banjo) and slowly push the piston back in.
Watch the reservoir don't overfill itself.
What you're effectively doing is pressure bleeding using the caliper to force the air out the top. Sounds a bit flaky... but it works.
Yes, it can be hard sometimes to re-fill a completely empty system and get it to build pressure. I start out using a Mityvac vacuum pump to fill the system, then switch to the old fashioned hand pumping to finish. Air bubbles will often be trapped around the MC piston and where the line connects to it. You can often free them up by pulling in the brake lever and letting it snap back open (bleeder valve closed). Do this several times in rapid succession while watching the fluid in the reservoir for bubbles floating to the top. You can also tap on the side of the master cylinder and where the line connects with a plastic screwdriver handle as you pump and release the lever.
Something else you can do on stubborn ones is "back bleed" them, that is, force fluid up from the caliper into the MC reservoir. But you'll need a Mityvac (or similar tool) for that. It has another "port" on it that pushes pressure out. So, bleed it normally until the bleeder hose is full, then switch the hose to the "pusher" port and pump the fluid back in and up into the MC.
Something else you can do on stubborn ones is "back bleed" them, that is, force fluid up from the caliper into the MC reservoir. But you'll need a Mityvac (or similar tool) for that. It has another "port" on it that pushes pressure out. So, bleed it normally until the bleeder hose is full, then switch the hose to the "pusher" port and pump the fluid back in and up into the MC.
does the wheel roll freely? Take it for a short ride use the brake a time or two, does it still roll freely? if it starts to bind your compensation port is blocked. It's a very tiny hole a pin is a good probe.
Yes if the lever is not pushing on the piston at all.
which is a possibility if you have the handle adjustment screw and lock nut threaded way in. that can also cuase hard lever. cuz a little pressure causes the piston seal to block that port, by design.
My point on checking after riding it; If the port is blocked, when the bike is ridden and stopped few times, the brake fluid which expands when warm, has nowhere to go and causes hard lever, pad dragging.
It is pushing on the piston but doesn't move as much as I think it should. And yes the handle adjustment screw are almost fully in
The lever MUST NOT push on the piston when no lever is being applied.
