[Guest (MBNZ)]

This is a common problem on the W140. Probably the most common problem.<br> <br> 1. Re-boot the 'system'. Remove fuses #3, #6 #9 & #11 from the trunk fuse box. Count to 10 or 20 and put them back in. Actually, not all of those are necessary to remove, but those 4 cover the bases. This will often cure the problem for many months.<br> <br> 2. If the fuse trick isn't working for very long any more, then replace the pump. It is in the trunk, just forward of the LR shock absorber tower. Just start removing the trunk liner parts starting at the trunk sill, then tail lights, then floor, then sides, then the forward piece exposing the pump. Disconnect the Bose radio (above and to the left of the shock tower) and slide it out to get the pump out. <br> <br> New pumps are about $700 at the dealer or rebuilts are available from http://www.programainc.com/ for $260. <br> <br>

 

[Guest (MBNZ)]

This is a common problem on the W140. Probably the most common problem.<br> <br> 1. Re-boot the 'system'. Remove fuses #3, #6 #9 & #11 from the trunk fuse box. Count to 10 or 20 and put them back in. Actually, not all of those are necessary to remove, but those 4 cover the bases. This will often cure the problem for many months.<br> <br> 2. If the fuse trick isn't working for very long any more, then replace the pump. It is in the trunk, just forward of the LR shock absorber tower. Just start removing the trunk liner parts starting at the trunk sill, then tail lights, then floor, then sides, then the forward piece exposing the pump. Disconnect the Bose radio (above and to the left of the shock tower) and slide it out to get the pump out. <br> <br> New pumps are about $700 at the dealer or rebuilts are available from http://www.programainc.com/ for $260. <br> <br>

 

[Guest (MBNZ)]

THANKS FOR THE INFO

 

[Guest (MBNZ)]

Is this also common on the '92 600 SEL? The pneumatic door functions are the only 'problematic' areas mine. Sure would like to do this less expensively (normally $1k each time...)

 

[Guest (MBNZ)]

Kathy,<br> <br> I understand that all W140s with door assist have this recurring problem. Fortunately, it seems to be the only recurring problem.<br> <br> Also, fortunately, if you are handy at all with your car you can repair this yourself for less than 1/3 the cost. I will be replacing my pump again in a few days and will post instructions and photos at http://www.serenitysys.com/MB/index.htm

 

[Guest (MBNZ)]

Steve,<br> Thank you for all the information. I went to the site you left and will check back from time to time. No, I've never repaired anything on a car. However, given that I'm intelligent - I think I can follow directions... we'll see.<br> Thank you again,<br> Kathy <br> 1992 600 SEL<br> 1989 535i BMW

 

[Guest (MBNZ)]

Before you buy a new vacuum pump, make sure<br> there is no leak in the tubing system.<br> The vacuum pump will shut the leaking system down (the others will still work) in order to prevent damage. <br> Check the switch in the door, there are two switches, one will activate the pump as the door is partly closed, the next will shut down the pump<br> when the door is fully retracted.<br> You can check the switches by connecting a test light to the connector at the pump, wich is located behind the rear seat on the left hand side in the trunk, remove the covers carefully after taking out the little plugs and rings around the speakers.<br> The light is turned on when the door partly closed and off when the door is fully closed.<br> when you are at it remove the plastic cover around the trunklock and check the trunk locking system as well (and the optional extra lock and especially the vacuum/pressure operator) for wear, tear and leaks because if this fails you can not open the boot without painfull destruction<br> <br> enjoy.

 

[Guest (MBNZ)]

Are there any major consequence of ignoring this repair. Doesn't the door still close, lock etc?

 

[Guest (MBNZ)]

The vacuum closing system is a luxury item only it does not affect the normal locking function.<br> The only tricky system is the extra lock in the trunk, which can not be operated by a pushbutton like the normal lock and needs the vacuum / pressure system to operate (open). If you don't trust the extra lock simply remove the hook.<br> Make sure the tubing is secured air-tight for vacuum and pressure.<br> The normal trunck-locking system is a complex bit of machinery, several actions are taken when opening or closing the lid, the extra lock and the normal lock recractor are released and the Clean Hand Lid is pushed out.<br> On closing, the retractor pulls the lid shut, the extra lock is closed and the CHL is pulled in.<br> If you want to (partly) disable the system<br> make sure you remove and cap the right tubing. <br> It could well be that the CHL is functioning ok, so you could leave it operable.<br> If not, you can use the lever inside the trunklid closest to the rear window to retract it.<br> Use the other lever to retract the normal lock hook (this action is normaly done by the vacuum)<br> or the lid will be secure but not fully closed.<br> If you do not remove all tubing you will have to repeat these actions everytime you close the lid.<br> Have a nice ride. Atze