He is right. If your modulator will not hold a vac, it is bad. What color vac modulator do you have? It must hold a vac to work properly.

On the original 1981 vac modulators, the cap was just a black rubber cap. You removed it, turned the T pin, and replaced the rubber cap. The rubber cap was to hold vac.

If your Mityvac will not pump up and hold a vac by placing it on the trans modulator nipple, the trans modulator is bad. Or maybe it was installed cockeyed.

Yup, its deffo bad, there is some resistance there but gauge drops from half to zero in maybe 3-5 seconds.

Dealer looked up correct unit which is brown (but looks orange), three day delivery door to door from Germany at around $100.

Weather is starting to turn here, will get the old one off next week or two and report back -

Last attempt removed trans cross member which wasn't enough, this time will take off engine mounts letting the engine rest on wood - hopefully this is enough to get that last bolt.

Bowden cable has been tweaked to hold onto gears longer, will need to re-adjust - have the procedure somewhere but need pressure gauge fro proper job.

__________________
David


1996 Mercedes S124 E300TD - 129k - rolling restoration project -

1998 Mercedes W210 300TD - 118k (assimilated into above vehicle)

You might consider giving our sponsor Pelican a call. Maybe they have one. Also think Bergstrom has them.

It would be great to support Pelican but unfortunately other side of pond in UK, just came across this excellent Corteco manual for 722.3, 4

https://www.scribd.com/doc/24267811/Mercedes-722-3-722-4

__________________
David


1996 Mercedes S124 E300TD - 129k - rolling restoration project -

1998 Mercedes W210 300TD - 118k (assimilated into above vehicle)