They can be a little tight ... I had discussions with one of JMG's mechanics (apparently it's one of John's favourite tasks to give the novices!) about getting them off. You can just tap them to loosen the bond, they will come off eventually, heat is always a good thing in moderation...
My Cab was relatively simple as I'd taken off the radiator and A/C cooler so I could get at everything through the front which makes things a lot lot easier IMHO - especially if you're doing belts as well simply because you can see everything and reach everything without any significant obstruction. I don't recall any major difficulty getting the puller on - are you sure the puller's 'teeth' are sharp?
The other thing that nobody tells you is that the crankshaft key is different to the camshaft/balance shaft keys. The crank key is what is known as a feather key which looks like a section of rectangular bar (imagine a long thin brick) whereas the cam and balance shaft keys are conventional woodruff keys
The woodruff key can be pushed out normally, but the feather key must be lifted out - best with a pair of end cutters.
I didn't realise this and was banging away at the 'stuck' key thinking it was a woodruff, but all I was doing was jamming it harder into the keyway. I ended up having to weld a small lever onto the f ucker to get it out.
HTH
Greg
