[Asshat]

Originally Posted by truckin 79

Those look similiar to the calipers on the rear of my 79 Trans Am. They are a screw in style of piston for the emergency brake. The piston works with hydraulic pressure during normal braking. When applying the parking brake there is a threaded screw in the back of caliper piston that attaches to that arm It puts manual pressure against the rotor to keep it from moving.

I already have the Eldorado style hydraulic/mechanical calipers.

I'm wondering if anyone makes a mechanical caliper just for parking brake applications. It looks like that is the one I linked from Wilwood. I will have to call them and check.