Do you still have the E-brake parts in the rear axle? There is a universal brake handle and cable available that pivots and locks in both the on and off position by rocking "over center" against a spring in both modes. There is an adjustment screw built into the knob for fine tuning the application force. I think some Jeeps used it- - - -specifically the military M-151 I once owned. My 65 Dodge D-100 pickup also used that type of parking brake.

For instance- - - -brand new:

https://www.ebay.com/itm/152057793036?hash=item236759ca0c:g:LrsAAOSw2GlXE1ik

Used ones are available for considerably less.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!