Well the front passenger door decided not to auto close anymore. The rest of the doors work wonderful but for some reason this one stopped.

I am hoping somone may have an idea on what to do? Replace the unit? I just dont know where to start. Any help would be much appreciated.

1995 s320

if you remove fuse # 9 in the TRUNK for 10 seconds will that (closing assist) start working again?

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Thank you very much but I really dont get it?

All the other doors worked perfectly, I pulled that fuse like you said and all was fine. The trunk was out of whack then but I reset it again and it was fine.

Is the pump going bad? Or does that door leak vacuum and the pump turns that section off after time?

Sorry for all the questions, wondeful fix, but I would love to undertsand it.

Thank you again!!

Its one of those 140 things, the circuit is designed to shut of after three tries based on the timing parameters. If you pull the fuse it resets it, this will probably result in a increase of your mean time failures, untill you replace the $$$ pump. Ther are two schools of thought. One is that the locks get stiff over age causing the failure inthe time allocated. I respect that since it could affect the timing, mine is that MB desinged it too close. I am on the third in 14 years, 96, 00, and 92, plus and minus they good willed it the last time. There were no other changes other than the trunk handle re-route in 96 and no leaks.
There have been people on various forums that have messed with the pump adjustments, no brass ring yet.

The pump can be shut down on certain individual areas, such as the front passenger door, rear trunk etc. Its not that the pump completely shuts down and all items dont work but individual items?

Can this be correct???

Is this the pump under the rear passenger seat??

Thank you

Once the servo assist stops working on one or more doors it signals that the pump is out of comission. It will do it only in one door, alternate between various doors or the trunk. Usually the pump controls all doors and the trunk through independent vacuum lines, although I don't think they can independently be turned off for a certain door.

The #9 fuse reset will help for a very SHORT while, but be prepared to change the pump sooner than later.

The servo assist pump for the doors and trunk is located on the trunk, driver's side, behind the upright panel just under the speakers. The pump under the rear seats controls the power locks and the lumbar support on seats. Completely different pump. Both pumps are expensive to replace $$$.

As mentioned, many forums have tailored with the idea of adjusting the pumps, although it seems the only real way to solve the problem is a new pump. Good luck!

__________________
A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]

Yes, but the added run-time of the pump will only accelerate
the replacing. Have a look at this good explanation;

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

I also seems to remember someone replacing just the inner pump/motor
with a cheaper VW part, but I cannot find the article.

br,
syljua (sadly without closing assist...)

__________________
1998 CL500 W140
1984 230E W123

WOW is all I can really say!!! HOW wonderful to have so much information!

Thank you so much, I think I know have a understanding of this pump.

Now the vacuum lock pump is different in the electronics? The reason I ask is on "my car" the drivers side door unlock tries to work but just does not have enough strenth it seems to unlock, but locks fine. When its really hot outside about 90 plus or so it works okay. Is that also the locking pump motor or something else?

Can the strenth and durration be adjusted on the locking pump as well?

THanks again for the wonderful information, I printed that one web page up and put it in my files.

The lock pump is not as prone to failure, before I would replace it I would lube the mechanism in the door that is giving you issues. The pump is under the passenger rear seat. There is a wonderfull tool called MIghty-Vac it allows you to draw a vacuum and a guage to see if it bleeds down due to a leak. The locking pumps also serves the lumbars, gas door , headrests in non elecric situations, back up rods, and sometimes the trunk handle, it also provides back up vacuum when the engine does not for the HVAC. It runs forward for pressure and backwards for vacuum. Pressure to unlock vacuum to lock, but it could be the other way

Here you have image of my pump central locking pump;



(Klikk on image for larger version)




As you can see, the shutoff pressure/vacuum for each outlet can be adjusted
on this one as well. Do not remember which line goes to what, but that
is described in this thread;

http://www.peachparts.com/shopforum/showthread.php?t=116085

I belive also that a leakage in the big red tube is fairly common.
Please remember that the pump look different over the years of
W140 production.

br,
syljua (still with no lumbar pressure... but have not visited MB either)

__________________
1998 CL500 W140
1984 230E W123

Hey very interesting, so you think its possible to adjust the central locking pump as well for the drivers door? Its only a problem with un-locking. locking works great! Fantastic pictures!

If you lived closer I would buy you a big cup of coffee!

Thank you!

Well, I am not sure, but I think the adjustments can be done separate for
the drivers door and the rest of the 3 + the trunk lock?). I think
you have 1 or more of 4 causes here;

1. Unlubricated door lock.
2. Adjustment of unlock (pressure) in pump too low.
3. Leak in tube inside from pump to shutoffvalve (that
will be more affected in a pressure situation than a vacuum one)
4. Leak in the line from pump to lock.

My best guess would be that you test the door lock, then the line
to the lock and finally open the pump and adjust. Beware, not
to dissassemble the electical socket to the pump. I did that, instead
of just dissconnection the whole plug assembly. A nigthmare
to get together again...

br,
syljua (smells the coffee from far away;-)

__________________
1998 CL500 W140
1984 230E W123