1981 300CD Brake Dragging still w/ new caliper

Aloha guys,

Back brake started dragging intermitantly for about a month, replaced both back calipers. Now it's worse! I can't even make it a mile before it's egg fry hot. Had to pry the caliper off, could not get the piston to return until I pulled the brake line off, then it went in smoothly.
Is there a valve or obstruciton preventing fluid return? It's only the back passenger side. I'm ready to disable the back brakes if I can't figure this out!

Thanks
Chris

I would suspect the brake hose or master cylinder.

Sounds like the rubber brake line; replace all 4.

They usualy fail internally and won't let the fluid drain back, keeping pressure on the caliper. Its a good idea to change them every 10 years, cheap insurance.

__________________
2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200