Lost my rear brakes
Posted January 24, 2009 - 11:57 AM
Posted January 24, 2009 - 03:05 PM
Last time I went riding I noticed I had almost no rear brake. I could lock up the tire but only if I completly bottomed out the pedal. I got around to bleeding them today and found no air bubbles in the line and I still don't have any feel at the pedal. I have plenty of pad thickness left and there are no leaks at any of the fittings. I'm thinking I have an issue with the mastercylinder, what do you guys think? Anything else I can troubleshoot to pinpoint the problem before I go ordering parts?
-Cracked Banjo fitting
-Torn master bladder
It takes me 20-40 minutes of bleeding to get a tight hydrualic circuit. Or a power bleeder.
Posted January 25, 2009 - 10:44 PM
Posted January 31, 2009 - 12:37 PM
Posted February 01, 2009 - 09:40 AM
Posted February 01, 2009 - 10:32 AM
I replaced the master cyclinder kit and I'm still not getting any pressure at the caliper piston, in fact the caliper piston won't compress in at all. I pushed the piston in to push air bubbles from the line up through the reservior. Now the piston won't move push out at all so does that mean my problem is at the caliper? Fluid will squirt out the bleeder so the master cyclinder is pushing fluid so what's going on here?
I had a similiar problem during my first ride on my 450, the rear brake went away. I had several problems that day due to the extreme cold, and assumed that the brake line had cracked from the cold. I rode home and found the line intact and the reservoir full - no evidence of leaks anywhere. The brake pedal pumped like there ws nothing connected to it. I bled the master cylinder and it did push fluid out of the bleeder, but weakly - not much pressure. If you have a lot of air in your system the first few bleeds will be weak pressure, but mine didn't get any better.
I thought it must be the piston seal leaking pressure, since there were no fluid leaks, just pressure loss. I had a spare from my 400 and popped that and it worked perfectly so I left it mounted. That was a year ago. I did buy a spare used 450 master cylinder, but haven't installed it since the other is working fine, and I still felt it may have had something to do with the cold.
I had very few cold issues with my 99 400, but the 07 450 seems to use less rubbery more plasticky stuff, so it cracks in the cold. The speedo wire snapped in half on the 450 when I rolled it out the door, before I even rode.
Was it cold when you lost your brakes?
Posted February 01, 2009 - 03:29 PM
Posted February 01, 2009 - 10:02 PM
Posted February 16, 2009 - 01:59 PM
I tried sucking fluid through with a Mityvac, pushing fluid through with a syringe, bleeding the conventional way, all to no avail. The only method that worked was tieing the brake pedal down with a zip-tie and letting it sit for at least 4 hours, cut the tie and then strap it down again. The first time i got a weee bit of pressure at the end of the stroke, the 2nd more, and the 3rd time I had pretty good feel at the pedal. What a PITA, just glad I wasn't messing with this during summer, I would've smashed something.
Posted February 20, 2009 - 07:32 PM