And NO, I haven't gone nuts looking through here yet but will as time permits.
My 85 Vacuum system has suddenly started acting up. Hopefully symptoms will be clear enough that maybe someone can point me in the right direction to find what broke.

Lock Car with key, only front doors lock, trunk locks but not fuel.
Lock Car inside by pushing lock button, nothing else locks but driver side.

Engine shutdown, 1 Mississippi, 2 Mississippi, 3 Mississippi and engine is off.

Shift is firmish but feels good (has not changed), brakes are strong.
Brown VAC line with red stripe that comes from down and back of the fuel injector pump and leads to that little horror show thing on the firewall. All the other lines in that thing are tight, the above mention line will move in and out. This line I am thinking is the main shutdown control line. Does it lead to someplace near the ignition switch?
I'm hoping there's a common failure for this, front door element? Big yellow line to the vacuum res in trunk feels nice and tight, I didn't want to disturb it too much.

Thanks a million.

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1985 300D 197K - Semi-Daily Driver Diesel
1998 Volvo V70 AWD 226K - Daily Driver 2
1998 Volvo S70 140K - Wife's DD
2003 GMC Sonoma ZR2 Option - Rusty Truck
THE BABY 1958 220S Sedan 66K All original, never restored and never will be.

That vac line goes through the firewall, to the ignition switch.

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83 SD

84 CD

I would be a bit more suspicious of doors that don't work than ones that do.

Last week my Engine would not shut off, Doors would not automatically open and unlocking the Front Door did not unlock the Trunk as it normally does.

I opened the Hood with the intention of hooking the Shutoff circuit up directly to the Main Line hoping I would at least get the Engine to shut off.

I pulled off the Hose that runs from the Main Line to the 4-way connector (Locks, Climate Control and supplies the Vacuum to the Shutoff) and found the Hose end had a nice split in it.

I cut the Hose back further and stuck it on and that fixed it so far.

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84 300D, 82 Volvo 244Gl Diesel

Check the passenger side front footwell below the carpet. It's easy to get to, so easy to check for secure fittings.

Clearly locking with the key is done with the engine off, but do the locks behave the same with the engine on or do you lock the driver's door from the inside before starting?

If they work with the engine running, then I'd suspect a reservoir leak and/or check valve leak but have good vacuum elements (i.e. when you have a good, active, source of vacuum then they work). If they don't work at all, then it widens the options.

A/C flaps all work okay?

A "good, active" vacuum source can overcome leaking actuators, whereas those same leaking actuators will deplete the reservoir in short order.

This sounds very close. I did replace the main vac to brake line recently. I accidentally leaned on it while fixing the window squirters and snapped the white/grey thing in the middle. I put new three and four way rubber connectors in place but maybe I screwed up a line while pushing it in place.

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1985 300D 197K - Semi-Daily Driver Diesel
1998 Volvo V70 AWD 226K - Daily Driver 2
1998 Volvo S70 140K - Wife's DD
2003 GMC Sonoma ZR2 Option - Rusty Truck
THE BABY 1958 220S Sedan 66K All original, never restored and never will be.

Where is the check valve mentioned here? I know there's a few check valves here. Doesn't seem to change engine on or off. I checked under the floor at lunch time and all is secure. I even found some kind of old paper slip that was put there when the car was built! Guess noone had much trouble with this car.

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1985 300D 197K - Semi-Daily Driver Diesel
1998 Volvo V70 AWD 226K - Daily Driver 2
1998 Volvo S70 140K - Wife's DD
2003 GMC Sonoma ZR2 Option - Rusty Truck
THE BABY 1958 220S Sedan 66K All original, never restored and never will be.

Check valves are the yellow-ish things on the vac lines in front of the firewall. There should be one on the yellow lines. The black/gray thing that broke was also a check valve. Was that replaced?

With the recent repairs to the vac lines under the hood, I'd start there for checking/troubleshooting.

Exactly. Pouring rain now, guess it'll wait. Yeah, the black grey thing was part of the line. It was the main vac line from the pump to the brake booster, all one piece. Noticed my tranny started banging a bit more shifting into gear. I had that happen while I was driving with the broken vac line semi-patched together while waiting on the replacement. I'm guess I've got a cracked line. The center vents in the car haven't ever worked for me but I'm not sure if it's a vac issue or a fried ACC box. A project for a later date.

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1985 300D 197K - Semi-Daily Driver Diesel
1998 Volvo V70 AWD 226K - Daily Driver 2
1998 Volvo S70 140K - Wife's DD
2003 GMC Sonoma ZR2 Option - Rusty Truck
THE BABY 1958 220S Sedan 66K All original, never restored and never will be.

There is a Check Valve that screws into the Vacuum Pump. Over 3 years ago I lost Vacuum and removing the Vacuum Pump Check Valve and Spraying it out with WD-40 restored my Vacuum.

Others have found the inside plastic parts of the Vacuum Pump Check Valve Broken.

Remember that the Brown Tubing that or Brown with strip attaches to the Shutoff Valve that is mounted on the Steering Wheel Lock. The short pieces of Hoses there can also be a source of Vacuum Leaks.

The Plastic Valve that is on the main Vacuum Line is called a Non-return Valve but some refer to it as a Check Valve.

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84 300D, 82 Volvo 244Gl Diesel