Shimano xt disc oil leaking problem

[Jean-Sylvain]

Hi! I have a problem with a disc brake I just bought from a friend. The
problem is as follows: when I installed the brake on my bike, I
tightened one of the screws that tightens the two peaces of the caliper
(my discbrake is a shimano xt a couple years ols with 4 pistons)
together. Since then, oil is leaking betwin the two peaces. I
disassembled the calliper, changed the o-ring that was sealing the oil
passage between the two peaces, put it back together, but it changed
nothing.

I don't see what's the problem. The o-ring should be perfect, the brake
was working perfectly when my friend used it (I'm his riding mate so I
know it for sure beside the fact my friend is really honnest), the
calliper received no hit since then. I don,t see how I could place the
two peaces more perfectly alligned.

If someone can help me here I would really appreciate. It's the first
time i will try a disc brake and can't wait to see how it wil work on
wet conditions (wich mean in Quebec, normal conditions).

Thanks in advance.

and please forgive my poor english.

Jean-Sylvain

 

[Phil, Squid-in-Training]

Jean-Sylvain wrote:
> Hi! I have a problem with a disc brake I just bought from a friend.
> The problem is as follows: when I installed the brake on my bike, I
> tightened one of the screws that tightens the two peaces of the
> caliper (my discbrake is a shimano xt a couple years ols with 4
> pistons) together. Since then, oil is leaking betwin the two peaces. I
> disassembled the calliper, changed the o-ring that was sealing the oil
> passage between the two peaces, put it back together, but it changed
> nothing.
>
> I don't see what's the problem. The o-ring should be perfect, the
> brake was working perfectly when my friend used it (I'm his riding
> mate so I know it for sure beside the fact my friend is really
> honnest), the calliper received no hit since then. I don,t see how I
> could place the two peaces more perfectly alligned.
>
> If someone can help me here I would really appreciate. It's the first
> time i will try a disc brake and can't wait to see how it wil work on
> wet conditions (wich mean in Quebec, normal conditions).
>
> Thanks in advance.
>
> and please forgive my poor english.
>
> Jean-Sylvain

Make sure it's absolutely clean between the two parts of the caliper before
you reassemble. Maybe there are some paint chips in between them?
--
Phil, Squid-in-Training

 

[BarryNL]

Jean-Sylvain wrote:
> Hi! I have a problem with a disc brake I just bought from a friend. The
> problem is as follows: when I installed the brake on my bike, I
> tightened one of the screws that tightens the two peaces of the caliper
> (my discbrake is a shimano xt a couple years ols with 4 pistons)
> together. Since then, oil is leaking betwin the two peaces. I
> disassembled the calliper, changed the o-ring that was sealing the oil
> passage between the two peaces, put it back together, but it changed
> nothing.

It's possible you overtightened the screw and warped the metal. You
might be able to check by putting the edge on a piece of glass and
seeing if it is perfectly flat. If it's not the LBS might be able to
help - otherwise you could try the desperation measure of tacking a very
fine piece of sandpaper to a piece of wood and grinding down the mating
surface to level it out. I have actually managed to repair a warped
cylinder head in this way before...

 

[Shaun aRe]

"BarryNL" <[email protected]> wrote in message
news:[email protected]...
> Jean-Sylvain wrote:
> > Hi! I have a problem with a disc brake I just bought from a friend. The
> > problem is as follows: when I installed the brake on my bike, I
> > tightened one of the screws that tightens the two peaces of the caliper
> > (my discbrake is a shimano xt a couple years ols with 4 pistons)
> > together. Since then, oil is leaking betwin the two peaces. I
> > disassembled the calliper, changed the o-ring that was sealing the oil
> > passage between the two peaces, put it back together, but it changed
> > nothing.
>
> It's possible you overtightened the screw and warped the metal. You
> might be able to check by putting the edge on a piece of glass and
> seeing if it is perfectly flat. If it's not the LBS might be able to
> help - otherwise you could try the desperation measure of tacking a very
> fine piece of sandpaper to a piece of wood and grinding down the mating
> surface to level it out. I have actually managed to repair a warped
> cylinder head in this way before...

Maybe better to use the sheet of glass again and some water based paper glue
to stick the 'fine' sand paper to that. 'An old trick' taught me by a very
creative engineer.


Shaun aRe