I think this is what I did.....1982 300SD... had just replaced trunk vacuum locking element with the vacuum/pressure pump in trunk disconnected both electrically and pneumatically. Then closed trunk as normal assuming key lock was the only lock. Came back a few hours later and trunk would not open even when unlocked and external plunger pushed in. Can only figure that I left new element extended instead of retracted? And this is somehow keeping trunk lid closed, even with lock turned and pushed from outside? Any ideas how to open this thing? I certainly will appreciate some help. Thanks.

I believe you may have two separate problems. The vacuum actuator and the lock tumbler.

If it were my car, I would use the key in the trunk lock and see if you can coax it to release to the unlock position. I would also shoot a bit of WD40 with the little spray red snorkle into the key opening and move it around quite a bit until it allows you to open the lock by simply pushing the button in.

Haasman

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'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
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'65 911 Coupe (#302580)

of your thread it sounded as if you were IN the trunk too.

Ha!

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Do you have the key outside the trunk I hope? If so try inserting it and partially turning it and push in the button to see if you can engage the release lever ;try it at different positions until you get it and there is a trick to aligning those damn things too; as you prob know by now. Good luck ...

Tom said from the sound of my post that I must be in the trunk also! It was worse.....most of my tools were in the trunk that day. When talking to the oldest parts guy at the mercedes dealer I was reminded that the key in the trunk tumbler should override the vacuum element in all circumstances. Of course I had proof in front of me that this was not so! But it gave me the reinforcement to do what many suggested and just keep jiggling and prying. It eventually sprung! I found that the tiny rod which connects the vacuum element to the tumbler is very sensitive in its adjustment distance. A little too much in the wrong direction and the plunger in the trunk lock still pushes in but the latch does not release. This is easy to watch and adjust WHILE THE TRUNK IS STILL OPEN. Thanks for the responses, this forum is a great backup.