Bleeding brake lines?

Fellow thumpers,

I recently disassembled the entire front end of my '01 426 to thoroughly grease the front head set. Everything is operating better than ever with the exception of the front brake. After reattaching the claiper, line, master cylinder and lever I noticed no resistance against pulling the lever - no brake. I proceeded to bleed the line numerous times with no improvement. After a while I had another brainstorm and hooked the front caliper to the rear brake line, which I knew was functioning properly. Only did the front caliper not work this way, now I have the same problem when I reconnected the rear brake. No front brakes, no rear brakes, no riding, no happy. What am I doing wrong. Thanks.

timdawg- bleeding brakes can be a pain. I have found that it's easier to fill them from the bottom with one of those old-fashioned oil pump cans. Just go down to Pep Boys and get a cheap one and some 1/8" rubber hose (or fule line works even better). Attach the hose to the squirt can and to the bleeder bolt on the caliper. Hold the brake lever or tape it against the hand grip and squirt away until your reservoir is full. Hopefully you'll be a happy rider again... Oh yes, this gives me a chance to brag a bit too. My son entered his first moto today and took first overall. He raced the mini quad class on his little TRX90 and did great except for stalling at the gate on the first moto. He battled his way back up to take 2nd in the first moto and with my help at the gate he took the hole-shot on the 2nd moto and never looked back. This kid is so terribly timid evrywhere else but get him on a quad and he is a mad-man! OK, I'm done now :)

Mike've got trapped air somewhere. Try unbolting the caliper and holding it above the master cylinder while you bleed the brakes. This will help push the air out. This is hard to do with 2 hands so you'll have to support the caliper with books or hang it form the ceiling. Just make sure its above the master cylinder. Also tap the line with a wrench or something, this will help aid the process.



These guys are right. Everything is fine, you just have some trapped air. And it's pain getting it out.

You can try a vacuum pump as well. And make sure the caliper pucks are slightly extended as well. If not, for some odd reason, the bleeding process won't initiate.

And congrats Mike to you and your son!!


Just wanted to pass on some info on a VERY cool tool I picked up a couple of years ago that literally turns the somewhat painful chore of bleeding motorcycle brakes into a job that can be accomplished in literally seconds without even touching the brake pedal or lever. The tool is known as a “Mityvac”. It is simply a vacuum pump you connect to the bleed valve. Top off the fluid reservoir. With the bleed valve closed, you create a vacuum using the Mityvac, then crack open the bleed valve allowing the air and fluid to be pulled from within the brake system and into a catch bottle (also under the vacuum) that comes with and attaches to the Mityvac. Once the air bubbles subside, quickly close the caliper bleed valve and Eureka! You are done. It really does take only a few seconds. As with all bleeding operations, you need to pay attention the fluid level in the reservoir and not allow it to run dry. There are several models of Mityvacs available. The one I use (P/N 6820) cost $30.00 (US). I've seen them at Pep Boys, and Harbor Frieght & Tools. Further info can be obtained from this link

Hope this helps.

Happy (open) Trails


The problem is probably trapped air at one, or both, of the banjo fitting junctions. You can bleed these the same as the caliper, but it's messy. Just pump-up the master cylinder and slightly crack-open the banjo bolt(s) the same as you would the caliper. This has worked for me in the past. Just watch out for plastic and painted sufaces.

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