Master cylinders cannot leak externally without internal seal leaks affecting braking. Ie, pedal goes halfway down, indication one brake circuit has failed - if pedal bottoms; both circuits are affected…so…?
Basically; the external seal is just a dust-cover - there should be no fluid inside it.
master cylinder seal kits are inexpensive, and should be renewed, as they go soft after many years
It should be possible to inspect & hone the bore once apart
(the bore is ever so slightly stepped inside)
if it is not acceptable, sleeving can be done, I had mine sleeved in SS anyway
carefully check the new seals, it is possible to get one too “long”…if you do, the MC will not bleed out the rear ports at all…I believe this is a supplier error
The brake master cylinder was the culprit. the seals were rather mushy
Fortunately for me the bores were i great shape, no honing required. I did notice lots of junk in the brake master, the culprit, a perished brake cap seal. Any suggestions on where I can get one?
The new seals from xk’s unlimited were a bit different, but the orientations (cupped sides facing forward) were noted.
The only issue I had was the front piston seal, couldn’t really sort out how to take it apart, so I just placed the seal over the stem.