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Hi
I've had a set of Deore M596 brakes for about 5 months now, and have been very happy with them untill the last week or so. The front it still fine, however the back now pumps up to the point where the brake is always on and the lever has no travel at all. It return to normal after about 10 mins, but 3-4 pulls of the lever and its solid again.
I've tried returning the pistons, cleaning the muck off the calliper, and made sure both pistons move easily (which they do).
Only thing I can think to do now is bleed it, but as the actual lever feel is still fine I doubt it's that.
Suggestions please 😕
Ta
Pip
Sounds like it's fubarred.
Buy one of the cheapo ones from CRC.
Shimano don't do spares for repairs.
Unless it's under guarantee of course, then take it back.
What Mary says.
Sounds like a sticky piston, but there ain't nothing you can do about it, especially when a new caliper is only £25 (which is the cost of a service kit for many brakes): http://www.chainreactioncycles.com/Models.aspx?ModelID=67226
I would definitely bleed it first of all. Logically you've got something expanding in the lines and pushing back on the lever and pistons, that will either be air or contaminated mineral oil. I'd check your seals/bleed nipple is intact at the same time.
I think you need a special bleed kit to use but that would be my first call. After that they are so cheap at less than £40 an end they are disposable...
As already said try bleeding it first.
Yeh that's pretty much the conclusion I had come to. I'm going to bleed it, as I have oil and kit to do it. A bit annoying, but as you said they are cheap so I shouldn't moan.
For anyone who is bothered. This was fixed with a full bleed. Bit strange to need it after only a few months, but least its fixed.
Also a bit of useful info: Avid bleed kit syringes fit the lever thread. Although obviously you need to clean them with alcohol or similar to remove any trace of DOT oil first. It means you don't need to buy another bleed kit.
Glad I've been proven wrong! 🙂