1987 300TD Wagon back hatch question - PeachParts Mercedes-Benz Forum

crashone · #1 05-24-2014, 09:47 PM

Today I locked the back hatch with the key, when I returned later to open the hatch the key turned and seemed to unlock the hatch. However the hatch will not open. It is like it is still locked. I tried to open it from the inside by locking and unlocking it but it is still not opening.
It seems like something may have come loose inside the hatch.
How do I open the hatch now? Can I dismantle the hatch from the inside enough to see what is going on?
Thanks.

dieselbenz1 · #2 05-24-2014, 10:25 PM

Don't give up after only one try lock unlock from inside. I had one that this would happen to every so often and maybe 10 to 15 cycles of lock unlock never failed. I did end up changing out the whole locking mechanism after a few years of searing for a used one.

crashone · #3 05-24-2014, 10:35 PM

Didn't just give up after one try, had to get down the road. Worked it several times after I got home too. Almost like it wants to catch when pushing in the lock button but then just fails to open, like it is still locked but I can see the lock plunger moving up and down.
Cheers.

vstech · #4 05-26-2014, 09:51 AM

do your autolocks work? when you lock/unlock the back door, do the other doors follow? unfortunately, you cannot use the autolock to UNLOCK the back door if it was locked with the inside lock, or the key, but it's something to check...

jay_bob · #5 05-26-2014, 01:16 PM

Somehow you are going to have to get that carpeted panel off the lower half of the back door to access the mechanism.

Normally you would open the door and take off the plastic trim cover on the bottom edge of the door, that is held on with about a dozen plastic pin fasteners. That frees up the bottom edge of the carpeted cover. I think it's hooked at the top with some clips to the framework of the door.

But since you can't get the door open that is going to be interesting. Maybe you can force the panel upwards enough at the top to get it released from the clips. Hopefully without breaking anything.

Once you get the cover off then look at the service manual, there is a procedure for adjusting the locking mechanism.

jay_bob · #6 05-26-2014, 01:32 PM

I thought of one more thing.

If you have a Mighty Vac (or your mouth), try putting pressure on the yellow hose from the pneumatic pump. The pump is under the carpet below the 2nd row seat on the right side.

The central locks use vacuum to lock and pressure to unlock.

vstech · #7 05-27-2014, 12:09 AM

another thing to try before you tear into the door...

have you tried to LIFT the door once it's unlocked? it's REALLY heavy with the shocks dead... maybe they failed after you closed it?

crashone · #8 05-27-2014, 09:51 AM

Thanks for the replies. I got it working again. The key would move the plunger up and down and appear to be unlocking but it was not traveling as far as it should. I found this out by getting a little frustrated and pulling on the plunger from the inside and having it move enough to get unlocked. Once open I removed the plastic and carpet strip on the bottom and found 2 bolts that hold the mechanism in place were loose. Tightened them up and checked all the other bolts as well and sprayed some dry lube in there and it seems to work like it should.
Interesting as I never would have thought to look at those bolts if it had not failed.