Bleeeeeeeeed!

I've bled fast. I've bled slow. I've bled at the master . I've bled at the caliper. I've bled til my hand stopped working. Still, my front brake is crap! What's the deal? (01 YZ 426)

Not sure but something worth trying. Put the cap back on the master cylinder, and remove the cylinder from the bars. Hold it up, so the lever ball is the highest point. Hold the cylinder and work the lever in and out. Also, have someone lightly tap the brake line, working from the bottom to the top. Sometimes, if the brake line has a point higher than the master, you get air stuck in there. The only way to fix it is to have the cylinder as the highest point. Might be worth a try.

you may need to rebuild your master cylinder.

saw a guy this weekend who had a similar issue but was solved by just replacing the entire master cylinder from another yammie.

I had the same problem as you and was pretty frustrated, till I tried a trick recommended by Eddie Sisneros. Take a large syringe, about 60cc or so, fill it with brake fluid, attach a plastic tube to the end and the other end to your bleed fitting. Fill the tubing with fluid before connecting to the fitting so as little air as possible gets inside. Then with the master cylinder cover off, inject brake fluid into the system from the bottom. Either let the fluid overflow at the top, or periodically siphon off the excess with another syringe. Worked like magic for me.

Air can be stubborn to get out of the front brake, but I wonder if you're really working with an air problem. All you can accomplish by bleeding is to get the air out and end up with a firm lever feel. But if the brake line is old and springy, it will only ever be just so good.

Also, if the pads are contaminated, they won't stop well, even with a good hydraulic system.

I don't mean to discourage you from getting the bleeding right, as long as you're sure that's where your trouble is.

could the plunger rubber or seal in the master cylinder suck in air?

They can, but in that case, they usually also leak fluid externally.

I've bled fast. I've bled slow. I've bled at the master . I've bled at the caliper. I've bled til my hand stopped working. Still, my front brake is crap! What's the deal? (01 YZ 426)

I bet you have a small stubborn air bubble in the caliper. Heres my fool proof method for removing those air bubble gremlins..

Remove the caliper completely and hold it in your hand, crack the bleeder screw so fluid slowly exits the screw. Gently roll the caliper around in circles in all directions , keep and eye on the fluid exiting, if you see a "slosh" you just removed an air bubble. If you see a steady drip, that means no air. This method I do all the time, and trust me, you will end up with a new "factory feel" rock hard lever feel.

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