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Problem with Vacuum Lock System

5K views 10 replies 3 participants last post by  emanlocious 
#1 ·
The vacuum pump in the trunk of my 2000 C230 Kompressor has started running for a much longer time after it functions. The length of time the pump runs after each function is as follows:

Lock Doors: 2 seconds
Unlock Driver's Door: 10 seconds
Unlock Other Doors: 20 seconds
Open Trunk Lid: 11 seconds

I removed the the trunk panel over the pump and found eight vacuum lines. They are labeled as follows:

3 White Lines on a Manifold: Heck/KAF
3 Yellow Lines on a Manifold: BFT/Fond
Single Yellow Line: FT
Single Yellow Line: Tank

I assume "Tank" means the vacuum line that locks the gas filler flap; what are the others for?

Is this the beginning of the end for the vacuum pump or is there a repair I could try? New vacuum pumps cost almost $500!
 
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#3 ·
I removed the vacuum line manifold and pressed a finger over each of the connections on the pump, then pressed unlock on the remote. The pump still ran for about 20 seconds. Does this confirm that the pump itself is at fault?

All the locks work; I'm just concerned that the pump is headed for failure.
 
#4 ·
There was a leak in the fuel flap lock mechanism. I sure would have saved a lot of troubleshooting time if I'd checked to see if the flap even locked!

I just plugged up the end of the vacuum line. I would have to have a lot of gas stolen before I'd break even on whatever Mercedes wants for that mechanism. Thanks for the help.
 
#6 ·
It just so happened I had my soldering iron set out (actually, I had to have it out to repair the wire I broke in the vacuum mechanism) and saw that a piece of solder wire fit into the vacuum tube. I cut off a piece and put it in the tube and touched the end of the soldering iron to it to melt it and the plastic to fuse them. Then I slid some shrink tubing over the end, heated it, folded it over, then placed another piece of shrink tubing over that and heated it. A bit obsessive I admit but I spent most of the afternoon and evening on this and wanted to make sure it never leaked again.
 
#7 ·
Among my misadventures troubleshooting this problem was closing the trunk when the vacuum mechanism was disconnected then discovering that the key wouldn't go into the trunk lock. I ended up taking the rear seat apart and crawling into the trunk to reconnect the vacuum mechanism to get the trunk open. This seems to be a common problem; the mechanism gets jammed as it is not often used because the remote is more convenient (and far less painful than using that little key!). This could lead to a real problem if the vacuum system fails and someone gets low on fuel. The key won't open the fuel filler flap. How many people, even if they could get into the trunk, would know to remove the left part of the trunk liner, including how to pop off those plastic clips, then reach up behind a metal strut and pull the manual release knob while simultaneously opening the flap? The Operator's Manual tells how to do this, but it's not under "Fuel filler flap," you have to look under "Manual release of fuel filler flap." Not M-B's best idea. I think I'm better off without a locking fuel filler flap.
 
#9 ·
Its annoying. But, Open the trunk. Take out the floor mat (the one that hides the battery and spare tire), then the right panel (the fabric one in the car), needs to be taken out. Its hard plastic almost so you need a little force, but pull it out from the car. I suggest start pulling it out by the head light first, and then the whole thing should just lift out, very simple, just tedious. From there you will see a foam box on the side. Carfully pull it out and on the inside is your pump. If you have any questions on how to get to it or fix it so that stops, just reply back or message me. If you would like pics of the process, I can post some.
 
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