Central Locking Vacuum Pump: Repairable?
 

1989 260E

My vacuum door locks have stopped working because the vaccum pump under the back seat does not appear to be producing suction.

When I turn the key in the lock, and put my ear very close to the pump, I can hear it hum -- although MUCH more faintly than its normal, louder hum, which I could hear from anywhere in the car.

Sounds like whatever motor is in there is failing. Are these pumps fixable, or do I need to replace it?

Dear Eric Silver,

There is a site with a realy good explanation and pic's on the following web site. Good luck!

Danny

OJs W124 Tech Tips : Central Locking System

http://ow.no/mb/w124/tech/electrical/centrallockingsystem.html

Danny,

Thanks for the info; it's very good.

I know, however, that the pump itself is at fault. I am wondering if it can be easily repaired, or does it need to just be replaced. (I hate to buy something new if a simple and cheap fix is available.)

Pump is not reparable.....l bought one on Ebay for $60, has been working well for the past yr or so, dealer wanted $800 for new.

Arif,

I did just that -- bought one on Ebay for $30, and got it today. Will install tonight. Hope it works -- and thanks for the scoop.

Well,

The pump is in and works fine.

I suspect the old one burned out because I have a leak, it seems in the fuel filler door vacuum element, causing it to run, on unlock/pressurization, for too long. (Over a few years, those extra thirty seconds per unlock event probably add up.)

I have no idea how to remove the element, and would probably be content with bypassing it.

Gas Tank flap
 

I think the diaphram is available, probably not a major repair. The entire assembly for a 560SL is less than $25, and the diaphrams for up to 84 were $7,or plug it untill you decide (Golf Tee)

I Peter,

Thanks for the scoop. I will definitely do both of those -- plug the vacuum line for a a few days, and then install the replacement diaphragm after ordering it.