# leaking disc brake - Shimano Deore M595



## KrzysztofMTB (Sep 9, 2013)

Dear All,

I am having hell with my deore m595 brakes. First I thought it was winter snow mixed with mud and dirt / **** from the road that made the brake pads dirty and decreased the breaking efficiency by 90%. I rinsed them with water and for 1-2 minutes they worked great. Then the same story... I invested in new brake pads. At first everything was great after a short period they failed again. Pouring with water solves the problem for a minute then the same story. I inspected the brakes and I can see there are some bubbles when depressing the lever. I replaced the gasket but decided to wait until 2 pairs of pads wear out before buying new ones. Sometimes they work better sometimes they are crappy. Strange that water makes them more adhesive (not logical - I thought water makes the braking distance longer in cars etc). Anyway now I inspected the brake - I have the same leaking bubbles problem - again.
I think this might cause that some mineral oil gets into the pads and ruins them.
this is a clip of the bubble problem.
leaking shimano m595 disc brake - YouTube

is it normal? should I replace the gasket again? or perhaps buy a new whole damn brake?


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## rangeriderdave (Aug 29, 2008)

The seals on the caliper/ piston need to be replaced .Once you get fluid on the pads they are almost worthless. You can try sanding or baking the fluid out /off. Easier to replace them.


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## KrzysztofMTB (Sep 9, 2013)

So the seals lasted 5 months. made in china or what?! I baked the pads. Not so good results. but smelled bad in the kitchen  Anyway is it normal that the seals in shimano are weak?


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## elcaro1101 (Sep 1, 2011)

Did you put the pads in place right after baking them? Doing this could possibly heat up the piston seal and damage it. I don't think this is likely, but who knows what a set of oven temp brake pads could do. Those bubbles shouldn't be there for sure. As posted above, that seal is bad again and needs replaced. If the same happened last time, then either you damaged the seal when installing the replacements, the heat issue I suggested above, or the caliper has a defect causing the premature failure.


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## the-one1 (Aug 2, 2008)

If you bought them new or with a new bike and there is still warranty on them, get them replaced (the caliper). You can't replace the seal on Shimano brakes as they don't sell spare parts for them.


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## AndrwSwitch (Nov 8, 2007)

They probably are made in China, next to almost every other consumer product. IMO, that's not that meaningful. Chinese factories manufacture to whatever standards the client pays for.

Sometimes you have pad luck with a part.

If you ride off-road, sometimes grit gets somewhere bad and causes premature wear somewhere.

Cold weather probably doesn't help. Rubber gets less resilient with falling temperatures.

I'd have the seals replaced and put it out of my mind unless it came up again. If it does, you might look on the fat bike forum and see what those guys are doing.


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## time229er (Oct 30, 2013)

*I would concur...*

that it sounds like pads/rotors are becomming contaminated...are you loosing any oil or are levers getting squishey? I might suggest getting your LBS hooked-up as you may also need to have them bled. Could be a piston/caliper seal also. The M595 generally does a very respectable job. I have M615 and love them. I would bet that a good bleed, a set of new pads and cleaning the rotors with alcohol would get you where you want to be...that is assuming you do not have a leak in a caliper!


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## KrzysztofMTB (Sep 9, 2013)

The brake isn't loosing oil, at least not material amounts. Levers are also not giving the rubber, squishey feeling. However sweating the bubbles of oil for sure can cause contamination. Now I am also wondering why isn't the piston totally hiding in the caliper? Is this normal? On the front brake also one of the pistons doesnt fully retreat, but I am not having issues in the front so maybe it is normal?


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## AndrwSwitch (Nov 8, 2007)

I believe the pistons retreat relative to where they were stopped by the rotor. So if your rotor is off-center, the pistons will retract asymmetrically.

IMHO, mountain bikers are way too precious about their brakes. I wouldn't worry about the pads retracting unevenly if neither drags (badly.)


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## KrzysztofMTB (Sep 9, 2013)

I dont want to waste money on a new gasket. I can buy either the same m596 calliper or a m615 SLX calliper which is 7$ more expensinve. Will it work with the rest of the set (handle + tube) or I shouldnt mix and buy exactly the same replacement?


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## time229er (Oct 30, 2013)

not sure what the "handle & tube" you are referring to are...if you are talking about the brake lever, the M615 caliper shouldn't know the difference...$7 is puppy-poop, but to be on the safe side I would just buy the M595. Good luck :yesnod:


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