Mike, The parking brake is indeed a separate drum type on the 87 300D and it is integrated in the rear rotors. Man, those German engineers are nothing if not efficient.
...I have'nt found a good diagram of the ebrake control cable or pedal release assembly but I'll shout out when I find one! In the meantime, check out the link below for the way your ebrake assembly is actually configured http://www.performanceproducts4benz.com/Drawings.aspx?bmid=83
The problem is probably an issue with broken internal springs in the e-brake assembly at the inside of the rear wheel rotors since you have no braking performance whatsoever. Parts are less than 50 bucks and a set of brake pliers from Sears...I've no experience with the cables but they're cheap parts at $30. Although they may be complicated to replace and adjust properly...again refer to the Haynes manual or search the forum for previous discussions. There is a lot of good stuff posted in past threads if you take some time to search for it.

Someone warned earlier to not mess with the cables but did'nt give any rationale. Maybe they will elaborate so you can figure out the best route to take to get these repaired.

Good luck and motor on

__________________
Bama1


2008 SLK 280, Firemist Red - "Hurricane"
2001 F150 Lariat 4x4, Black on Black - "Badboy"
1982 240D 4 speed survivor -"Pearl" - Donated to Vietnam Veterans
1962 Oldsmobile Dynamic 88 -"Gertrude"

1954 model original owner - ~2.5M
Gray softtop/solid exterior/modified chassis