W140 boot lid closing problems

[LazyBob]

Does anyone have any experience of temperamental boot lid closing on a 1998 W140?
It's got a remote boot release button in the dash and a remote on the remote if you know what I mean, it always springs open OK but sometimes when I close it, it won't close. It just sort of bounces off the latch.
I can get it closed if I manually push the latch on the bottom of the boot and then unlock it with the remote (or button). Then when it does close, the little boot tongue slips away into it's little hole and then ten seconds later it slips back out and the remote switch light comes on.
This doesn't happen all the time but it seems to be getting worse.
As far as I can tell there are two locks on the boot, when the car is locked the boot is locked (even if the the little boot open light is on) when the car is unlocked the boot is sometimes unlocked (if the light is on) sometimes not (when the light is off).
It's got the self closing doors and boot so you can hear the whoosh from the compressor, so I don't understand why the little tongue comes back out after it appears to have gone back in OK.

Any thoughts most welcome.

 

[Shude]

Probably an alignment issue, there is a huge range of adjustment on the bootlid and the lock/latch mechanism. If it's even slightly out of alignment then it causes problems.

 

[guydewdney]

iirc theres a few threads on this on some yank w140 forums - im not at home at the mo' - so dont have the links to them. try googling for w140 and forum...

what year is yours? pre 1996 ones have an issue with brreaking off small vacuum pipes on the compressor (in the boot, lhs iirc) easily fixed with araldite. new pumps are v v v exbenzive.

 

[markku]

Little tongue

It's got the self closing doors and boot so you can hear the whoosh from the compressor, so I don't understand why the little tongue comes back out after it appears to have gone back in OK.

There are two separate vacuum systems in your car ( relating this problem ). Self closing door and boot locks are powered by the pump in the boot. The other one is controlling the central locking and the small tongue, pump located under rear seat.

Please check all tubing and actuators for leaks, the pumps should not run for more than few seconds after every activity.

This problem has been discussed numerous times in US forums. The forums guydewdney was referring were most probably these, use search.

http://forums.mbworld.org/forums/forumdisplay.php?forumid=29

http://www.mbnz.org/forums/forums/forum-view.asp?fid=13

http://www.mercedesshop.com/shopforum/forumdisplay.php3?f=1

Congratulations for your nice taste of cars, btw

 

[LazyBob]

Shude, Guy & Markku - that's given me plenty to look at.
Hopefully it is an alignment problem - I tried again with it tonight and it closed properly but I was leaning on the boot lid at the time, sorta holding it down - that gives me hope for alignment of the latch.
If it turns into a pump change (as the US Benz forums seem to suggest) I'll try to do a Haynes manual type photo story in case it helps anyone else.

Thanks & Happy New Year

Bob

 

[LazyBob]

Guy, Meant to add it's a 1998, all the other close assist bits seem to work fine.

thanks

 

[Shude]

I tried again with it tonight and it closed properly but I was leaning on the boot lid at the time, sorta holding it down - that gives me hope for alignment of the latch.

Thats what I had to do, I adjusted the latch until it fitted properly then when the bodyshop hammered the back end of my car into mercedes-shape again they adjusted the latch back for me . If it *is* the latch then it's a 5 minute job to sort out, and I discovered that the spanner in the oem toolkit fits it perfectly on the w202

 

[guydewdney]

if it is the pump - can i have the old one? - i want to take one apart and find out what makes it tick, and see if it can be repaired...