central locking system 1973/450sl
 

I am having trouble with my door locks. I believe I found the culprits aline in the drivers door and a line hooked to the gas flap y connector that goes behid the trunk and under the hard top. I also found a line that is y connected and runs through a grommet in the fender/firewall, Iam not sure if this is connected to the door and I can't see a clear path for replacing it if I pull it .It goes through the door and it is invisible until it reaches the grommet. HELLLLLLP !

You gotta remove the door panel to find out what's going on.

Three possiblities:

1. The vac switch is shot. Locks won't work, or will only work one way.

2. Broken line. Worst spots are in the rubber boot at the door hinge. Ditto for wires.

3. Bad vac actuator. Easiest way to check is to unplug the ones in the trunk and test with a MitiVac. There is no actuator in the driver's door, so if the gas filler and trunk lock work, the passenger door or line is bad.

Peter

central locking system
 

You mentioned a vacuum switch, where is it located? The trunk opens only with a key and the gas flap does not work at all. Any ideas?

The vac switch is in the driver's door next to the lock. Accessable once the door panel is removed.

The trunk and gas filler door actuators are the most accessable, that's why I would suggest checking them first. I've not messed about in a W107 yet, but I suspect the filler cap actuator is under a plastic cover up by the filler door inside the trunk. The trunk latch actuator is probably on the passenger side of the lock -- there will be a yellow with red stripe and yellow with green stripe hard plastic hose back there going to the trunk lock.

Go to the auto parts store and get a MitiVac hand pump ($35-40) -- this lets you hook up to the actuator and apply vacuum. There is a guage on the pump so you can tell if the actuator is leaking.

I would also check the yellow plastic line in the engine compartment -- they get brittle with age, heat, and engine oil, so it may simply be broken off. Not very likely that any of the locks work if any of the actuators leak.

However, if you have a leaking unlock trunk diaphram, it may lock but refuse to unlock.

Peter

cenyral locking system !FIXED!
 

I ordered a trunk, passenger vacuum element and a check valve from Fastlane on 12/23/03 and they arrived on 12/24/03. I replaced the passenger vacuum element,the trunk vacuum element and the drivers door check valve. The gas flap element does not fit my car. But now the locks gas flap and trunk are operating like a charm. Thanks so much for your help . You have probably saved me $200.00 in diagnostic fees alone. I will return the gas flap element.