Hello,
Am upgrading my 1985 Def90 to Td5 clutch pedal to try save my left knee.
Fitted new master cyl (black top) and now find that the pitch of the thread on this is different to the white topped one I took off.
Can anyone explain.....is it possibly a Series3 master cyl ?

The problem came to light as I was attempting to fit a lid to the cyl to pump fresh fluid in.
The lid of the pressure pump fits the old master cyl fine (white top) but not this new one (black top).

Strange and frustrating ;-(