w140 door assist pump replacement

[Victor300E]

Hello.
Car is 92 500SEL and it's missing door closing assist pump. I connected my friends pump from 95 S500 he has for parts. On his pump 2 pins are blank on pump socket but my plug has wire for missing pin. Pump closed doors but with some problems. It would start working after doors are closed and heat up a lot then will not close doors. Since I never had original pump and it must be a reason why it's not in car (broke?) so question is is 95 S500 pump intrerchangable with 92 500SEL pump? I need to know if they are so I can start troubleshooting whole system.
Thanks

[Peter Guenther]

The pump # is 140-800-08-48 im my 500sel in 97 and in 01
This should give you some reading matter
http://www.benzworld.org/forums/forums/thread-view.asp?tid=1220225&posts=3&fid=13
There must be issues to have someone remove the pump, the easiest way is just pull the fuse, and slam harder

[Victor300E]

Looks like all door close assist pumps are same and interchangable. By any chance do you have wiring diagrams of door assist system? I have mitchell repair manuals cds but they don't have diagrams for assist system.
thank you

[syljua]

Originally Posted by Victor300E

By any chance do you have wiring diagrams of door assist system?

An russian site (www.autolib.diacom.ru) used to have all Alldata
diagrams for the W140. I grabbed the diag. for my car before it closed down(?)

Remember, this is for a december "97 (MY98) S320, but things should be
more or less same.

Here are the Close assist. And since the responsibility of the release of the trunk
moved from one of the pump to the other thru the years, also the
Trunk release and the Door locks.

BTW, it sound like you having a slight leak in the pressure lines that will get
the pump to timeout as described in;

http://www.v12uberalles.com/Closing_Assist_Pump.htm

br,
syljua (wanting to aftermarket install Close assist!)

[Victor300E]

After looking at diagrams I finally understood the differencs between 92-94 pump and 95up pump. They are interchangable but 95up pump will not close the trunk since, as you noted, trunk assist moved to PSE pump. Now I have to research how to reroute vacuum hoses and electrical wiring to assign trunk assist to PSE pump if possible. Any ideas? Great web sites. Thanks again. Now I know I can buy 95 pump and look for leaks.

[Peter Guenther]

That somehow does not compute. In 93/94 the trunk handle was re routed to the "close assist" pump in a service bulletin. The whole upper actuator was replaced, a microswitch on that was bypassed, and a "t" was put in the line of the "close assist". I assume the port was capped, previously the "draw in" of the handle was handled by the "locking pump" under the rear passenger seat. That pump handles lock/unlock, lumbars, HVAC backup vacuum, rods if you got them, and vacuuum headrests if you got them, and of course the handle prior to the mod, and I think in later models (95?) controlled the trunk remote release.
I would suggest getting the 140 DVD (92-99) from Mercedes if you plan on working on the car. it is good not great but has wiring and service info $150 or so.

[syljua]

Hmm, I can only tell you how it works on my car without the 883 code
(no Close Assist). The black line from the PSE pump, under the rear seat
handles both flap unfold/retract and trunk release. I guess the trunk release
is followed by the unfolding of the flap driven by the same pressure
(or vacuum?).

br,
syljua (wanting to buy retrofit kit 1407500584, but oh, so expensive...)