You can use this guide to diagnose why it wasn't unlocking along with the rest of the system.

Mercedes W123 Vacuum Lock System Diagnosis Technique - iFixit

Good trick. Good to post separately in the fix it threads.
The color combo of your W123 is nice.
(my first car was a 1962 Galaxie 500)

P.s. I think the cowel covers changed to black,like the 240D always had, at some point in the turbo diesel production period.
I also prefer the chrome colored ones.

I will be adjusting the valves this weekend. I decided to buy one Hazet 14mm wrench for a go by and I made the other one out of a Ace Pro 14mm which is thin so I did not have to grind it. I also got the third Hazet wrench too.

I have been searching for factory service manuals but not much luck there.

I almost have all the parts to build a pop-tester. I will be working on that too this weekend.

http://i1045.photobucket.com/albums/...ps2c5cdec8.jpg

http://i1045.photobucket.com/albums/...psecbfb81a.jpg

The Ace pro wrench next to a real Hazet. I got one Hazet to use as a giude. The third wrench was irresistible.

Love your old rotary phone!

Thanks cooljjay.
I pressure washed the enigne and bay but did not get around to adjusting the valves.
I looked at the turbo impeller and it looks pretty beat up. :-l
There is some play when I wiggle the compressor wheel. It feels like 1mm of play side to side but no play back and forth.
Where could I buy a new compressor wheel? Mercedes source has a nice looking 200k kit.
http://i1045.photobucket.com/albums/...ps8a69a099.jpg

I finally got around to adjusting the valve this weekend. I found every valve to be way too tight.
Wow! That was fun. No joking. I really enjoyed it. The third wrench is a lifesaver. I needed it on three valves.
Now the engine stars easier and will idle without stalling and revs up much better.
When I removed the valve cover I expected to see a lot of sludge but it is very clean.

Now to address the injectors, fuel tank and vacuume lines with an EGR delete. :-)

Readjusting the valves again with the correct feeler gauges. Took a pic of the valve timing while I was at it. Not sure if this is good or bad.
http://i1045.photobucket.com/albums/...psb0d156c6.jpg