Should I have 2? One to lock and one to unlock? Sneaking down the passenger side of the car are 2 vacuum lines: 1 going to the gas cap actuator and 1 to the "storage tank"...if I am missing 1 line where does it come from so I can replace it?
-shawn

Shawnster,

Do the trunk and fuel door lock and unlock properly? If they do, don't worry about it. If they don't we will need more info to help you sort it out. What color are the lines? They should have red or yellow srtipes, one may be solid yellow.


thebern

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1982 240D 313,000 (4 speed)
1984 300CD 172,483
1985 German Shepherd Dog -Lacey- R.I.P.11/04/05

Hood Stars, Wrist Crowns and Obsession Dobs

No, I'm having lots of vacuum troubles with the door locks and intermittent dieseling (no pun intended) on my 81 300td. I've done some general troubleshooting but haven't purchased a pump just yet. When I noted that the gas cap only has one line going to it I was wondering if that could be right? The actuator definitely has 2 fittings on it...

My haynes manual shows only one line at the fuel door, it should be yellow witha red stripe. Use the search feature here to find lots of answers. I can fax to you the mb service manual pages diagnosing vacuum problems. with diagams. Keep in mind I have a 240 but it is a 123 chassis so it should be close. You will definately need a mighty vac to systematically fix the problem. Get one with the brake bleeder as you can also use it to change brake fluid.

The intermittant dieseling is from a leak that won't 'pull' the 'shut off valve', to off, to stop the engine. Under the hood will be a red stickered lever that says 'engine stop ', push on it to stop the engine.

IMPORTANT: How long have you had the car? Did this just start? Has anyone, including you, been under the hood who may have 'nudged' a line loose? Do you have any manuals?

Vacumm problems are a royal pain but can be overcome. My car is fine except that their is still a leaking locking line that goes flat after about 4 hours. Hang in their, we'll help ya get it fixed!

I'm about to leav e the shop now and will get back with you in the morning.

thebern

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1982 240D 313,000 (4 speed)
1984 300CD 172,483
1985 German Shepherd Dog -Lacey- R.I.P.11/04/05

Hood Stars, Wrist Crowns and Obsession Dobs

Well, I've been under the hood checking all of the hose connectors there: I've replaced some of them (the ones on thermovacuum valve and egr) because they were trashed. I've inspected all others and they all look good, intact.

Because the problem started with the hatch I started there: inspecting the connectors there and then the gas cap. So does one of the gas cap actuator fittings just vent to open air? Weird-

Fax'ing me the diagrams would be AWESOME. You could also e-mail them to me if you want: townkraftdeluxe@uncleoscars.com.
I have the Haynes manual but not any of the MB manuals yet.

My 300CD has two lines going to the fuel flapper lock actuater. They are both the same color, but I'd have to go look to remember their color.

On mine both of these lines must be attached for the flapper lock to acuate and to not have a vacuum leak.

My 72 280 SE only has one line to the gas filler door lock, it appears to be spring loaded open so that it is locked with vac, but unlocks with spring pressure. The locks work, so that cannot wrong.

Look behind the cover panels in the trunk -- you may have a line broken off. If this is the case, you will have no lock function (or they will lock, but not unlock, or vise versa). Stray end may still be there. All the yellow with red lines connect together, and all the yellow with green stripe lines connect together. Yellow only is the supply line to the driver's door.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

My '85 has only one line (yellow w/orange stripe) running to the fuel door lock. The other nipple has nothing attached to it. The lock has a spring that causes it to unlock when the vacuum is released. I imagine that it was designed this way so you could still fuel your car if you had a vacuum problem. I think your plumbing is as it should be.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

No to belabor the point, but I posted earlier that I had two lines going to the fuel flapper lock actuator. Mine is a 300CD. I didn't post that the model is a 1981, like yours. The vacuum line diagram I have also shows two lines going there.

It may be that yours is supposed to have only one line. I'm only saying check carefully. Most of the others posting here do not have '81's. But, I've found on other Benzes I've owned, that not all models of the same year are exactly the same.