Vacuum problem, '81 240D . . . .

2 days ago, when I turned the ignition key off, there was a bout a 2 sec delay before the engine stopped. Yesterday morning it was a second longer. Last night, it would not stop at all. I had to go under the hood and press the kill lever. Also last night, ALL the locks quit working.

I thought the shutoff valve was going bad. It would appear that there is a vaccum leak elsewhere. There has been no work done on the car in the recent past, so no chance of something having been knocked loose.

I was thinking of checking the vaccum pods in the doors first. I really don't want to tear the door panels off, mostly because I don't know how. Anyone have suggestions where the most logical spot would be to start testing for the leak?

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1981 240D, Auto Trans, 160k miles -- CRASHED!

Rather than checking for a leak try to find out if the vaccum pump is still working first. If you find it is then start chasing potential leaks in the system. Your power brakes will be really poor if that pump is out or you have a heavy leak. If brakes are still good just start disconecting and checking all the branch circuits under the hood. Guy should have a mity vac type of device for this. You have a containment vessel in the trunk above the fuel tank I think to consider as well. Plus remember the brake booster can develop a bad internal leak. Look up a vaccum diagram on this site. At least the 240 has less of a vaccum circuit than the other models. It is sometimes a possibility to push door locks down manually with engine running to help identify if problem is in the door circuit. Shutoff will work sometimes with that done. Others may know of a common failure mode as think that is what you are looking for.

OK, I dissconnected the door locks from the vaccum system and now the engine shuts off normally. So, it would appear that I have to look at the doors for my problem.

I searched, but could not locate a pictorial on removing the door panels. Does anyone now where I can find one?

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1981 240D, Auto Trans, 160k miles -- CRASHED!

I have only done it once, but removing the door panels was pretty straight forward, especially on the rear doors. As I recall....and that could be a minor problem in itself.

Remove all the visible screws, the arm rest, etc. The window crank has a screw under the plastic trim piece (which can be popped off gently). There is a little black plastic piece behind the door handle that pops out to access a screw in there. Slide a flat putty knife or some such under the bottom of the door panel. (They make an inexpensive tool for this which you can get at any parts store.) Work around the bottom and up the sides popping out the little connectors. Then pull out slightly from the bottom and lift straight up.

If your front door panels have the plastic "pockets" there is a trick to removing them. After you have popped out the connectors around the bottom and sides there will still be a plastic connector from the pocket which sticks through the panel and fastens behind a piece of metal on the door. You need to slide the pocket (to the rear, I think, if not try forward) until the bit of plastic slides out from behind the metal. I did not know this, and broke my piece of plastic.

Gook luck, and maybe someone else will chime in who knows better than I do.

George

I've had mine off a few times, and george d has just about covered it. Just go slow and careful, you don't have to force anything. I believe the plastic tabs on the front map pockets lift up, BTW. Just move them around gently after everything else is disconnected and you'll feel them come loose. It may take 30 minutes the first time, maybe 10 or 15 after you're done it a couple of times.

DO NOT go tearing all your door panels off to diagnose a vacuum problem!

You can isolate it to a single door, or the trunk or the fuel filler using the vacuum lines under the carpet. They are MUCH easier to get to than taking off the door panels. For a tutorial, see my post here: regarding vacuum locks on 240d

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Rick,

Thanks for that post. I have printed it out for future reference.

I had to get into two of my doors to replace the door brake. My left rear door stuck open one time, and I absolutely could not get it to close. I finally had to remove the door brake to close the door. Luckily it was at home, and not out in a parking lot somewhere.


Luckily I have had no vacuum problems yet on my 1982 240D.

George

Rick, I printed your post you linked to. Thanks for the assist! Hopefully I'll end up only having to tear into one door to fix my problem, once isolated.

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1981 240D, Auto Trans, 160k miles -- CRASHED!