David,

Forget about breaker bars, the tire flex absorbs the shock you need to break
really tight nuts loose.  After giving it a try with torches, bars, hammers,
etc., go rent a 3/4" drive electric impact wrench and socket (remember that
standard socket size, they probaly won't have metric.)

Brrrruuup! Two seconds later you have it off or on. A big 3/4" (half inch
drive won't work) impact wrench is the easy way!

It will be the best $25 you've ever spent!

Stuart MacMillan
'84 Westy w/2.1