Re-drilling P-brake drum

[green40]

I'm swapping in a 3spd t-case and I want to redrill fore the bolt pattern
on the larger drive shaft yolk. How do I do it so that everything is centered?
Pics of the layout would be helpful.

 

[Poser]

Why not just locate a 1974-07/80 parking brake drum and not have to screw around with modifying yours?



I do not have any pictures of the drums that I have modified, but you need to use the end yoke from the drive shaft to seat into the pilot hole in the parking brake drum, and then use a transfer punch that fits the 11mm bore of the larger four speed drive shaft bolt holes in the end yoke to mark the centers of the holes.


Not worth my time for the screwing around involved; it is way too easy to get a parking brake drum with a compatible bolt pattern.

 

[green40]

I have a 74-4speed tranny and t-case in it now, isn't the output shaft
on the 3 sp t-case a different size (splines)?

 

[Pin_Head]

The splines are the same; the output flange bolt pattern is different. You can just swap drums, like Steve said.

 

[Tankota]

I redrilled my drum for another pattern several years ago. Used geo metro wheel studs. Sold it with the matching driveline when I swapped out the t-case. Even so I'd recommend finding another drum.
btw, last time I measured the 3spd joints were about the same size as a 1310;p so I can see why you want to keep the 4spd drivelines which are much beefier. Even so...I twisted the splines on the stock 4spd driveline once...u-joint was fine though.

 

[green40]

Thanks, swapping will make things a lot easier.