Car in question: 300CD w123

Ok,

Issue is door locks not holding vacuum and engine shutoff delay.

What I know:

coming from master vacuum switch in driver's side door:

solid yellow line doesn't hold vacuum
yellow red-striped line doesn't hold vacuum
yellow green-striped line holds solid vacuum

Resevoir needs a lot of pumping, but seems to hold vacuum from yellow grey-striped line on engine side of firewall.

Solid yellow line going into firewall from engine side,and ostensibly connecting to driver's side door master vacuum switch holds vacuum on engine side, but not at the master vacuum switch connection point. It looks like there is a dashpot under the dash connected to the yellow line going out from the driver's side master vacuum switch.

passenger side on floor:
lines to passenger door red and green striped hold vacuum
lines to underside of dash running to driver's side door hold no vacuum at all.

Lines running from passenger side floor to trunk and fuel door:
Yellow with green stripe holds vacuum
yellow with red stripe doesn't hold vacuum even when plugged up at connection to fuel door.

Trunk actuator is functioning fine.

Questions:

Do I have to remove the dash to test the dashpot connected to the solid yellow line running from the master vacuum switch in driver's door? Is there an easier way?

Does anyone have any advice for checking the door lock lines that run under the dash out of view? Can they be pulled through easily and reinstalled lower down and in view? Is there a way to fish new line through the current path with rubber connectors?

Do I need to replace yellow with red stripe line from passenger floor 3 way rubber connector to fuel door? How can I find cracks in places I can't reach or see?

How is it that the green striped vacuum line from driver's door holds good vacuum going into dash from driver's side, but doesn't hold vacuum when tested from passenger side floor where it exits?

Any suggestions would be greatly helpful. I'm determined to get the door locks right, and hope that this fixes the delayed shutoff issue.

Thanks.

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1982 300cd 245K miles and still goin'...