Easy done. The seal will come out with it though. Put a ring spanner under the nut (put a washer under the nut) & gently tap it upwards (might need a moderate tap). Make sure it's really clean (polished) when you put it back & it will probably have an indent in it from the pushrod which you'll need to de-burr. They can stick causing clutch slip until it comes free which is very frustrating.
K
