I have finally, after a week of waiting on parts, sourcing parts, and making the time to do so, resurrected my 500,000km blockhouse '87 Dieselbenz. My oil cooler, having been originally designed and OEM sourced from the sister S-class and mounted in a fairly retarded location in front of the front wheel, low, had been hit by a flying dome of fiberglass off the head of my Dalek (don't ask). 

So, after doing quite a bit of fighting with the lines, breaking some vacuum bits and repairing them in the process, knocking a diesel line loose, and generally fighting with things, I was ready to go at long last. (The lines had to be replaced because one was damaged.) After a short bit of cranking, it ran! Oil pressure back once again to the peg (idiotic Benz gauge scale), no leaks visible, no hisses, funny noises, or other warning signs; excellent. I went to turn it off to get it off the lift.

*stumble*
*continues to run*

"Well, shit."

It seems that I have almost no vacuum, thus meaning that my iron housecar does not have das power on der brakes. Nor der power locks. Nor either ability to shut the motor off without reaching under the hood and pushing a funny little lever that helpfully says "STOP" in white letters/red  background. Because if there's one place you should expect a stop sign, it's under the hood of a diesel. (It's a Mercedes thing - you wouldn't understand)

I believe free debris from a broken bit to have clogged my vacuum system just before the pump. Hard to fix? No. But right now I'm tired, and tempting as it might be to drive everywhere with bad brakes and raising the hood to shut it off, I'm going to stick with my loaner for another day, as some of my stuff is still in the German Abomination from moving and there is a threshold of redneck I shall not this day cross. Risking mortal brake peril, driving with a guitar on the back deck and a nightstand in the front seat, and raising the hood to cut the engine off is in toto a bridge too far.

Nicht Ausgezeichnet, as German Bill and Ted might say.