Rare brake piston internal mechanism removal

[natenate]

Rare brake keeps sticking. I have taken the brake apart and on inspection the brake piston was pretty pitted. Cleaned them up but had the same problem. Brought replacement but is says that the internal mechanism that drives the rear piston will have to be removed from the original piston and placed into the new piston and this is usually held in place by either a circlip or crimped in place. But I can not see any clip and I'm unsure how to remove it. Anyone done this before?

[Benz Dr.]

That piston is used on 300SE and 600 brakes. I think the BBB has some info on it. The caliper holds the pin which retracts the piston. Unusual set up but it seems to work OK. Exspensive brake pads though..........

[Tyler S]

Have you replaced the rear brake hoses? I had a similar problem, Pulling my hair out to find it. Rebuilt the calipers..still sticking. Went so far as to replace my left rear caliper with a new unit..was still sticking. I finally found out that the rear brake hose metal sheathing under the rubber had rusted to the point it was causing a restriction. The pedal works fine with the couple of hundred psi applying the brakes but wont retract because of the restriction not letting fluid flow back.