Outer Limits 4x4 Board

Recenty my HJ75 has been leaking fulid out the clutch master cylinder. It is weeping out of the piston inside the cab. Is there a rubber seal in there that can be replaced or is it a throw away sealed unit.
Cheers

You can get rebuild kits, but the bore of the m/cyl are easily scored/corroded. Less headache by just replacing it. May want to check/replace the slave while you're at it, they are where the crap ends up and normally last less than the master.