Wondering if any of the members here who have a pre 80 w123 know if there is any common place where a lock vacuum line may crack?

My locks were working great a long time ago....I thought the trunk pod was bad so got another one....still had an issue....then I thought the main vacuum valve was bad so I grab what I thought was a good one at the junk yard....that wasn't it....I figured one of the early vacuum pods had a tore rubber boot....well being board and no cash for parts....I tore every pod out of the doors, tested and inspect all are fine....even the gas door one.....checked the hidden connectors under the ducting all are fine.....so I hooked up the locks again....nothing...not even one popped up...like there is a disconnected line somewhere...and none of the vacuum accessories worked....

Guessing I might just have to wait till I can afford a mighty vac again....but just seems strange to have such a huge leak that none pop up and not be able to locate it visually...

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Well, being that no mighty-vac is yet available, do you have what FEELS like decent vacuum coming from the main line? Difficult to troubleshoot without that little tool...

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'83 240D 4 spd. manual - Undergoing OM617 transplant - Soon for sale.

'97 Dodge Ram 2500 Cummins 4x4 5-spd. WVO - Not stock. - For sale!

'06 Sprinter

Oh yeh, that is fine...my brakes are fine, cruise control works and even my evil servo is fully working....plus when I got the car a little over a year ago I pulled the top of the pump and checked the diaghram....I was amazed there was not a crack...engine dies right on the money too.

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This damn thing is giving me a migraine. So I found a leak, I forgot to attach the unlock line to one of the door diaghram....so fix that hooked everything up....let the engine idle but still no locks....unhooked locks....engine dies....I undid the door card....and used mouth pressure for yellow vacuum line feeding the locks...I am able to to unlock the doors and lock the doors using my tongue to keep the vacuum in......I ran out of light, but when I sucked the tank side line I also pulled a vacuum and it stayed......maybe my vacuum pump is worn and can't pull enough vacuum to operate the locks? I am stumped....

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Here are the diagrams for the 1980 W123.123 240D.
You may need to remove the egg crate (vacuum tank) and inspect for cracks or failing seams, the rubber vacuum tube grommet also fails with age.

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I did it! I now have a fully working locking system!

So if anyone else cannot for the life of them figure out where their leak is....replace the main vacuum going through the firewall and under the dash...

I noticed I could pull that line and get slack, thought there was extra line under the dash...I then couldn't get the line to hold vacuum....so I then went to the door and pulled on the line out of frustration...and it came out....there was a less then 1/2in rubber coupler holding the line in the door to the line under the dash right in the fold of the door.....I then noticed a check valve under the dash, one end was connected to the end going to the door...where as the end going through the firewall couldn't be found.....

I borrowed the vacuum line from the trunk to run a new line, I then relocated the check valve to the door.....everything works....even when the car is off.....and the car shuts off fine.....

No idea if the coupler in the accordion tube in the fold of the door is factory or not....but that was my problem....

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Who said you HAD to have a Mity Vac??

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

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