B**tard castellated clutch nut....

[Matt_Harrington]

I've not had one like this before and I bet the PO did something to it! (The clutch cover was literally glued on with some solid stuff either side of a gasket!) I have used heat, penetrating oil, air impact driver and even a 2ft breaker bar and it won't budge. (and yes, I've managed to 'spoil' the clutch backplate!) Before I attempt to drill the nut to then break it any other trick I can try?

[andy120t]

Are you turning it the right way ?!☺☺

[Matt_Harrington]

Isn't it a standard thread? ie undo anti-clockwise?

[andy120t]

..sorry, ignore me.. I was trying (failing) to be funny...

[Matt_Harrington]

Andy, under normal circumstances I would have found that funny but it has been a mare of an afternoon with this engine! 

[andy120t]

 :)hi

[Oddjob]

You have removed the tang on the locknut washer. It's bent over so the nut can't come loose

[Laverda Dave]

The only thing I can suggest is to use an induction heater on the nut itself. The localised heat applied just to the nut by the heating coil may be enough to break the seal on the thread between the nut and the shaft. A mate used one on the nut of a Muirhill tractor after trying everything else and the but just came undone!
Problem will be finding someone who has one as they are mega expensive to buy. Maybe try a local garage/mechanic. I'll ask my mate where he got his from, he lives in Buckinghamshire though so a long way from you.
I really wouldn't want to try and drill it off considering where it is and the shaft it is attached to.

[Matt_Harrington]

You have removed the tang on the locknut washer. It's bent over so the nut can't come loose

Yes, that has been done.

[Matt_Harrington]

The only thing I can suggest is to use an induction heater on the nut itself. The localised heat applied just to the nut by the heating coil may be enough to break the seal on the thread between the nut and the shaft. A mate used one on the nut of a Muirhill tractor after trying everything else and the but just came undone!
Problem will be finding someone who has one as they are mega expensive to buy. Maybe try a local garage/mechanic. I'll ask my mate where he got his from, he lives in Buckinghamshire though so a long way from you.
I really wouldn't want to try and drill it off considering where it is and the shaft it is attached to.

Interesting idea. I'll ask someone locally. I was planning on drilling into the nut itself to weaken it which I may still do ...

[davidcumbria]

When you say you tried heat was it enough. I have bought one of those  mapp torches and it’s incredible how much better it is than butane and heat guns. Same idea as the induction - just get it really hot and then use an impact driver.

[Matt_Harrington]

I stopped applying head when things started to smoke a little more than I would like! 
I have a couple of things to try today......

[McCabe-Thiele (Ted)]

Best of luck with the nut issue we've all had similar trials.

[Oddjob]

Matt what seems to be the main problem, the nuts bonded onto the shaft or that the shaft is spinning so making your efforts to remove it harder?

[Matt_Harrington]

The nut is well and truly bonded. I've put the chain back on and tried to stop the main shaft turning but I still can't shift the nut. I must admit that trying to stop the main shaft turning is not 100% successful.....