gearbox oil leak

[MICKREEVES]

My C15 has been leaking all its gearbox oil out in a very short time.
I  twice replaced the seal (Behind the sprocket),,  which is half a days work.
No different.
Now I have found that the tiny breather hole in the filler cap was completely blocked with rust.
I hope this will be the cure.
Mick

[AdrianS]

Have you confirmed the oil is leaking from the sprocket seal? Clean and degrease everything and refill and carefully look for leaks.If it is past the seal, is the seal damaged? Is the output shaft smooth or rough so as to damage the seal? Is the seal seated properly?

[MICKREEVES]

Yes, the seal and shaft all perfect.
I have just changed my sprocket from 17 tooth, to 16 tooth and fitted another new seal.
Should be good now
Mick