Looking for rear caliper 1988 Shelby Z rebuild tips

[chromguy]

Just before I rip my 88 Rear calipers apart and replace the seals/dust caps etc, any special precaution with regard to the wedge or other internals?

[chromguy]

The piston is removed by turning the allen key CCW, pushing the piston out


now with the piston out, you will notice a significant ring , the opening is at the 11am position.


I was planning to remove/clean the ratchet inside the piston but I cannot get the ring to pop out of the groove. Screwdriver and tapered awl did not work as the spring is very strong and the slots are small.
If someone has an idea, I will give it a try....otherwise I will use an industrial ultrasound with WD-40.