Wheel cylinder removal on a 47 2 ton

[mb300d79]

Gentlemen,
The rear wheel cylinders on my 47 Loadmaster 2 ton need to be replaced or rebuilt. The axle is out on the passenger side and the six-slot locking 'nut' needs to come off next. Locking tabs have been bent back. Brakes have been backed off.

The 'nut' is on so tight I can't budge it with the 1) correct removal tool, 2) with a punch, and 3) a combination heat and punch. We believe the threads are the normal counterclockwise turning to remove.

Any suggestions would be greatly appreciated.
Bill Alexander
Mansfield, Ohio