[W140 S320 Silver]

I posted a note asking if anyone had any advise on how to fix my vacuum door pump which will only operate a couple of times then fails. It also will only fail on a door by door basis, and you have to remove fuse 9 in the boot for 15 secs to reset it. Ok for the doors but the boot is noticable if it doesnt close.

So a friend and I removed the pump (located in the boot behind the rear seats on the left hand side, it just slides out). We checked all of the inputs from the doors with a scope, they were ok.

So if you take the six screws out of the pump (security Screws), inside you will see a row of coils a circuit board, motor and a preasure switch with two wires coming from it (circular, with a green and white wires and two air hoses). All we worked out was that the presure switch was out of tune so turn the screw in the centre "one" turn and reconnect the unit to the car. The doors worked fine. Saving £500. Im not saying this will solve all pumps problems but worth checking before you splash out the cash.

If you then reconnect the pump, goto the back door and put it on the latch, if it sucks the door closed but not all the way you have turned it the wrong way. The correct operation should be it sucks the door closed about 1-2 mm further than it should then relaxes slightly. The door is now closed. The pump starts up every time the door is sucked closed and then waits a few seconds when it starts again to presurise the system ready for the next time.

 

[HMCGARY]

Did the this solve the problem?...

Did the this solve the problem?

 

[W140 S320 Silver]

Its worked for nearly a year now!!...

Its worked for nearly a year now!!

 

[bazzis]

soft close doors

Would this work for my 1992 600 sel? can you explain a little more just where and how to remove pump, is it all done from inside the boot area? many thanks.

 

[Rainmaker]

Yes, where do we find the pump?

Also, thanks everyone for the earlier posts about r...

Yes, where do we find the pump?

Also, thanks everyone for the earlier posts about removing the fuse. When I bought my car, the vacuum for the trunk, plus 3 of the doors, was already not functioning. The trunk didn't line up with the body panel, and 3 of the doors didn't have the close assist. After pulling fuse 9, everything worked. It still all works. But I wouldn't mind finding the pump for curiousity sake.

thanks

 

[W140 S320 Silver]

Hi I can only speak for my S320 1992 but the pup is located as follows.

Stand behind th...

Hi I can only speak for my S320 1992 but the pup is located as follows.

Stand behind the car, open the boot and remove the left hand lining cover in the boot. The pump in mine is just next to the wheel arch between the wheel arch and the fuel tank. It is contained within a foam rubber casing, the whole unit should slide out towards the rear of the car, you can then remove the lid of the cover and see the unit inside.

It measures about 8" long, 5" wide and 6" high mine was maide by Bosch I think. It has about 8 small bore air lines attached to it.

Make a note of which air hoses go to which nozel as they are marked up in German!!!

The air pump is held together with secrity screws, be gentle when you take the cover off it slides upwards. The value I adjusted is connected to a hose and has a small adjuster screw on it. Just tighten it by half a turn and reconnect it. Dont over tighten it!!

You can see if it is too tight by look reseting the power to the unit then going to the rear passenger door and gently pushing the dooor closed so the Assisted close mechanisum starts to pull the door closed. If you watch the door close you will see how far the door is pulled in before it stops at its final position. In other words it pulls past it final resting place, if this is too much it may damage the mechanisum so dont over tighten the screw.

Good luck

 

[mckenna]

I posted a note asking if anyone had any advise on how to fix my vacuum door pump which will only operate a couple of times then fails. It also will only fail on a door by door basis, and you have to remove fuse 9 in the boot for 15 secs to reset it. Ok for the doors but the boot is noticable if it doesnt close.

So a friend and I removed the pump (located in the boot behind the rear seats on the left hand side, it just slides out). We checked all of the inputs from the doors with a scope, they were ok.

So if you take the six screws out of the pump (security Screws), inside you will see a row of coils a circuit board, motor and a preasure switch with two wires coming from it (circular, with a green and white wires and two air hoses). All we worked out was that the presure switch was out of tune so turn the screw in the centre "one" turn and reconnect the unit to the car. The doors worked fine. Saving £500. Im not saying this will solve all pumps problems but worth checking before you splash out the cash.

If you then reconnect the pump, goto the back door and put it on the latch, if it sucks the door closed but not all the way you have turned it the wrong way. The correct operation should be it sucks the door closed about 1-2 mm further than it should then relaxes slightly. The door is now closed. The pump starts up every time the door is sucked closed and then waits a few seconds when it starts again to presurise the system ready for the next time.

 

[mckenna]

I posted a note asking if anyone had any advise on how to fix my vacuum door pump which will only operate a couple of times then fails. It also will only fail on a door by door basis, and you have to remove fuse 9 in the boot for 15 secs to reset it. Ok for the doors but the boot is noticable if it doesnt close.

So a friend and I removed the pump (located in the boot behind the rear seats on the left hand side, it just slides out). We checked all of the inputs from the doors with a scope, they were ok.

So if you take the six screws out of the pump (security Screws), inside you will see a row of coils a circuit board, motor and a preasure switch with two wires coming from it (circular, with a green and white wires and two air hoses). All we worked out was that the presure switch was out of tune so turn the screw in the centre "one" turn and reconnect the unit to the car. The doors worked fine. Saving £500. Im not saying this will solve all pumps problems but worth checking before you splash out the cash.

If you then reconnect the pump, goto the back door and put it on the latch, if it sucks the door closed but not all the way you have turned it the wrong way. The correct operation should be it sucks the door closed about 1-2 mm further than it should then relaxes slightly. The door is now closed. The pump starts up every time the door is sucked closed and then waits a few seconds when it starts again to presurise the system ready for the next time.

which way doyou turn the adjustment screw; clockwise or conterclockwise. I have cl500 1996 with simiar problems.
thanks marc

 

[ackvig]

I'm going to give it a shot

W140, Rainman, thanks for the info. I've already pulled my pump and it's sitting on my kitchen table now. However, I started the project 30 minutes before I had to get to the bank before closing and the wife simultaneously had to go out of town. DOH! So, I'll make the adjustments, and when she gets back, see how it went.

BTW, I've had my 300SE for just over a year now, but just recently started posting. Will get a pic up soon

AckVig

 

[W140 S320 Silver]

I cant remember, I think clockwise. It needs to get tighter. If that helps......

I cant remember, I think clockwise. It needs to get tighter. If that helps...

 

[mckenna]

soft close doors

thank you sir!

 

[ackvig]

SUCCESS!

Thanks much W140, et al. As per your instructions, we have VACUUM! Folks, at least for me, it was as easy as following W140's 2 instructional posts and it fixed an $850.00 vacuum pump.

 

[ackvig]

SUCCESS!

Thanks much W140, et al. As per your instructions, we have VACUUM! Folks, at least for me, it was as easy as following W140's 2 instructional posts and it fixed an $850.00 vacuum pump.

 

[ackvig]

SUCCESS!

Thanks much W140, et al. As per your instructions, we have VACUUM! Folks, at least for me, it was as easy as following W140's 2 instructional posts and it fixed an $850.00 vacuum pump.