Is there a trick to getting the front brakes bled on a KLX300? Brakes got mushy so we tried....

1) Bleeding brakes with no luck

2) Rebuilding master cylinder with no luck

3) Replacing the master cylinder with no luck..

NO matter what I do, there is no pressure built in the master cylinder.

TIA


I read in a service manual for a KX500 that there is a special tool for bleeding brakes. Any info on this?

Quote

Have you checked for leaks? That little piece of metal brake line that is below the caliper is very exposed, and easy to break or mess up with a rock. First check that there are no leaks, and if there aren't, then you might try to just keep bleeding, it took a very large amount of bleeding before my brake was back to normal again.

Hope this helps
Kevin

You say they got mushy. Was this without anything being done? If so, based on what you have already done I would look for a problem with the caliper. The piston has to move out and stay as the pads wear. Sounds like maybe the piston is retracting more than it should or the caliper isn't floating properly so it is pushing on the rotor and flexing it rather than pulling the far pad against the rotor. Also one of the hoses could be damaged and swelling.

First, make sure there aren't leaks. You can actually bleed the system two ways. First with a plastic syringe and a hose from the caliper up. Tighten the caliper bleeder, then squeeze the lever and crack the caliper bleeder before the lever bottoms against the bars. Keep the reservoir full and repeat this with the banjo bolt on the handlebar reservoir. Before you quit for the night, take a rubber band, nylon tie etc. and pull the lever in to the bars to let it bleed the small bubbles all night. Your brake lever should be tight and predictable, not mushy.
Some TTr's recommend removing the brake caliper, tying it off above the bike and pushing fluid up through the system, then leaving it open to let the bubbles rise. Could be a mess if not properly executed.

Burnrider, I am one of those who will recommend removing the caliper and holding it higher than the reservoir on the handle bars. In fact, lay the hose out straight so any bubble doesn't get trapped in a dip in the hose. Now do the bleed procedure just like the manual says. Of course you need to have something holding the piston in place, newer brake pads are probably thick enough.

I had a real tough time bleeding the front brake before, so I finally removed it and that solved my trouble. The rear is not as big a deal because the height from reservoir to caliper is not as great as the front. You could have a leak or you may be having trouble bleeding them. Don't give up, a crappy brake is bad news.

hoghead, did you ever get this issue resolved? i am having the same problem with my 03 klx300 and i cant seem to figure it out! rebuilt master (old parts looked fine), but on a new brake line (Honda-style). When I pump the brake lever no fluid comes out of the master cylinder even if the brake line is not hooked up. any help greatly appreciated.

pull the caliper apart and clean it. check for cracks.