Is it the clutch shoes you are trying to replace (2 black pads on a metal bracket)?
Yes, two pads connected by a bracket with a key hole in the centre of the bracket, this held on a central spindle by a nut. the nut/spindle spins, and the housing also spins which makes removing the nut difficult unless you know the trick ?
I know what you mean.
What I used to do is get a socket on the nut with the ratchet and then hold the clutch shoes with one hand while undoing the nut with the ratchet.
Tricky I know but that's the only way to do it so try that and it will come off its just a case of holding the clutch shoes still while undoing the nut.
Once you get the nut off and you remove the shoes just watch out for the pin. This slides into a hole in the shaft and that whats keep the shoes in place so just make sure you don't loose it.