I was cleaning my car and adjusting various things this weekend. I put some lubricant on the rear drivers door as it squeaked occ-still does after lithium spray. I also pushed(not hard) on the accordion like rubber boot between the body and door. Yesterday I noticed a slight thump behind me as I drove-perhaps near the door. The noise did not change with speed and I could not hear it as I went faster and general noise increaseed. I think it is also there when I idle. The doors still lock fine though I have not repeatedly tested them yet.
Did I interrupt the vacuum system? Is there a danger in not fixing it asap? Should I just pull off the rubber boot or is there finesse required?
Thanks

What brand, make, yr, and model are we talking about here.

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I listened closer. The noise is actually 2 noises, the first slightly softer, da...Dump.............repeat in this cycle. It does persist when idling and seems to be coming from the door. That is why I thought it was a vacuum line I may have bumped.
Any tricks about pulling off the rubber accordion boot and fixing the line?

Once you lock or unlock the doors the pump no longer runs. I think the noise is something else and a coincidence to your lubing the door.

Peter

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I'm not familiar with your model MB, but on my W140, the fuel pumps are located in that area and will make a "humming" noise similar to you are describing.

This is normal.

Not really a humm. Very distinct "da" then a pause of 1- sec then another noise. Then a pause of 2-4 sec and repeat. I tried to locate it by sitting in the back seat and opening the door. I will look to see re fuel pump. Fuel filter is definately on passenger side and I think pump is next to it.
Thanks for the help so far.

RSM,
Unless you have incredible hearing like the six million dollar man, you shouldn't hear the pumps. If they are loud, they are on the way out.

100,
Another far out possibility is that the vacuum system is trying to dump the rear headrests on the 124. Climb in the trunk with the engine running and look up. You will see the mechanism that controls the rear headrests.

Peter

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