Master Cylinder Leaking

[UncleMike]

I went out to work on the bike today and without even touching it, the front brake master cylinder is leaking. What would cause this all of the sudden? Do I need a new cylinder or just a new seal?

Thanks,
Mike

I know where I can get a new cylinder from a '79 425L, but I can't find if this would be compatible as bikebandit doesn't have a fiche for the 425's.

[Anonymous]

Where is it leaking from?

On my round-reservoir master-cylinder there is an o-ring around the base of the plastic cylinder that fits snug into the metal housing. I would also believe that a leak could occur at the cap of the master-cylinder if it is not set up properly.

[UncleMike]

I'm not really sure. I haven't attempted a diagnosis yet, as I've never done it before. The underside has fluid all running down it. I'll look again in the light tomorrow and perhaps attempt to take it apart.

Does anyone know if that 425 master cylinder would fit? If so I'll just buy it anyway and keep it as a spare if I don't end up needing it.

[earlfor]

Not having either of those bikes Mike, I cant give you a guarantee answer, but I believe the master cylinders for the 400/425/450 series would all be interchangeable.

Earl

I'm not really sure. I haven't attempted a diagnosis yet, as I've never done it before. The underside has fluid all running down it. I'll look again in the light tomorrow and perhaps attempt to take it apart.

Does anyone know if that 425 master cylinder would fit? If so I'll just buy it anyway and keep it as a spare if I don't end up needing it.

[UncleMike]

Thank you sir.

I believe your opinion is valid enough for a $15 gamble.

[earlfor]

:-)

Earl

Thank you sir.

I believe your opinion is valid enough for a $15 gamble.