thanks everyone for the help. the rear chamber of the master cylinder had in fact gone dry. I filled it all the way to start. installed speedbleeders on rear calipers. I used a vacuum pump to get the dark crudy fluid moving. At the end I had clean fluid with no bubbles coming out. Took for a test drive and felt 110% better! My mistake was letting reservoir rear compartment go dry.
now for my next hurdle, a rear bearing!
97 MB E300D, 200k
00 VW Golf TD,I 225k
98 Chevy 3500 6.5TD, 208k
90 VW Jetta TD, 200k
87 MB 300 TD, 580k miles...RIP
If it has less than 200k on it, it's not for me!