shimano deor problems

[TrailSquirell]

big problem, shimano deor hydros that are losein breakin power really fast, my rear brake went from spot on 2 days ago to mush all the way to the bar practicly over night. I havn't crashed for the past week, yet i've been poundin at the skatepark practiceing my air. i've been told to just buy mineral oil, level the tanks, and refill them. would i be best off just flushing the sytem? any help would be nice, gota keep it cheap thow

[Pete Hamer]

There is probably something wrong with your brakes if they did that. It would be smart to diagnose the problem and fix it the first time. It could end up costing more if you do it wrong the first time. Do you see anywhere that the oil might have drained out from? There would probably be dirt/dust collecting around that area. If there are noexternal leaks then it might be a brake hose problem. Sometimes the inside tube cracks and allows the fluid to leak out of it and into the black outer casing. You won't find any fluid leaking because it's still inside the lines.

[TrailSquirell]

not seein anything leeking on the housing or anywhere on the caliper, looks like i'm in for new lines if fillin it back up doesn't work.

[Pete Hamer]

If it is a problem with the line like I was describing and you fill the brake with oil it will probably work for a short time then go mushy again. That type of problem is very confusing and usually difficult to diagnose. You can bleed the brake and it works a few times then goes back to the way it was and there is no visible loss of fluid. Each time you bleed it, it works for a short time then gets mushy again. People usually think it's something they are doing wrong during the bleeding process.