Vintage Cars: Mercedes 123 vacuum lock, mercedes 123, oak ridge turnpike

Question
Hi, I have diagnosed a leaking rear vacuum pod.  I would like to replace it, but cannot figure out how to remove the threaded rod from the pod.  There is a plastic cone shaped piece on top of it, and I only want to replace the bad part, and not break anyting.  I already tried unscrewing the upper portion of the plastic part from the threaded rod, but it only spins, it never "unscrews".
Thanks

Answer
Mike
It won't .
They are not repairable unless you have a special tool and the rubber diaphram
George Murphy at Performance Analysis sells the kits... or at least he use to
perfanalysis@comcast.net
865-482-9175
969 Oak Ridge turnpike
Oak Ridge, TN 37830

I think the last time I bought them it was like $50 for enough stuff to repair all of the pods, I also think he sells them individually,
THere is a special little tool that I recommend you get with the kits

Best I can do, good luck, I may have a used one laying abourt here if you have a part number I can look

Ron