Rear pinion nut

How do I remove the rear pinion nut?  The rear end is out of the
car.  I have tried holding the wheels in place with blocks.
I have tried bolting on a piece of metal to the pinion and then 
using a cheater bar on my breaker bar and the piece of metal.
The bolt failed once and the metal bent a second time.

Any ideas short of putting it back in the car and then undoing
the nut.

Bill Gilroy
77 Midget