I'm having a problem with the 'soft close doors' on my 1992 600se, if I remove the fuses for a few seconds the mechanism works for maybe a dozen times then stops, I then have to remove the fuses again, any ideas???

 

<FONT face="Times New Roman, Times, serif" color=blue size=2><FONT size=3>You most likely have an internal leak in the closing assist pump.I usually do just that, pull fuses # 3 and 9 in the rear fuse on the right side of the trunk.I then check all the doors and trunk. If closing assist works at all points tehnI replace the pump. It is mounted next to the gas tank, forward left in trunk. If you remove theleft trunk panel you can see the lines going to it, usually red.</FONT> </FONT></P>

 

I found someone stocking replacement vacuum diaphragms for the central locking systems in the older models (114, 123, 126 et al). He didn't know whether ones for the 140 series soft-close systems were available. Should I persist with the search or resign myself to paying the small fortune to replace the whole unit?

Regards

 

if the door closing aid only shuts down a certain door then you have to check for ny vacuum leak on a particular door, but if it senses or exceeded the threshold operating time (if multiple doors is operated at the same time), then it shuts down the pump.
removing fuse 9 is enough to reset it (3 and 9 if it was installed as option)

 

The closing pump is a known issue, if it attempts to close a door three times and not successful it goes into error mode. There are differing opinions on the failure: the lock needs to be lubricated, since the pump sees to much resistance! :the internal sensor shuts down the pump prematurely(safety factor) :the electronics fail, the vacuum routing relays fail in the pump since they are triggered by switches in the door and trunk lock. I have had two fail on my 92SEL the first in 97, out of warranty! The next in 03, but the dealer no-charge replaced it, probably from purchasing two new MBs lately.
There are people who have taken the pump apart and slightly tweaked the vacuum sensor, and claimed success, it also could destroy the diaphrams. These are not the diaphrams we know in the lock/unlock circuit and have seen no posts about any rebuilding being done

 

Thanks Peter
Mine is a 94 S500L. I am usually the only one in the car, so the main problem is the drivers door. As you have described, once reset, I can open the drivers door 3-4 times before the soft close "times-out" (you can hear the pump trying). The trunk and other doors seem to work a few more times before I need to reset it again.
Can you advise me on the sequence of my scrutiny - or do I just buy the new pump and be done with it?

Regards

 

It sounds like the typical failure=(pump). They are around $600, other than the dealer, and some person in Miami offering them on the internet Ebay, I would try George Murphy who is a technical director at Mercedes Club of America 865-482-9175 or george_murphy@compuserve.com he shows them in his ad in the magazine.
Buying one from a stranger can get you one no better than what you have, I have heard stories of "it worked when I shipped it"
Both of mine acted just like you described, It started with the trunk, then moved to a door, MB did the fuse trick. I got tired of doing that, they repaced the pump. The last time they did check the diaprams with a vacuum tester, and again replaced the pump!
There was a bulletin that certain pumps made in 95 or so had a defective hose internally (from the pump to the manifold) and a new hose was available for replacement.