I have a 82 300D thats blown up that I use for parts.

My 300CD calipers in the front started leaking, so I switched them with the 300D parts car. I got a rebuild kit for my front brakes which I will do this week along with the other improvements listed above. I may rebuild my rear brakes to be sure so I wont have to deal with it.

My front calipers now are from my 82 300d, and they dont leak, but the rear brakes from my 300cd are still on the 300CD and they lock. I am thinking the master cylinder still.

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Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.