W108 Door Lock Repairs - PeachParts Mercedes-Benz Forum

jrs3484 · #1 01-11-2022, 02:24 PM

I'm looking for some help in how best to get the door cards off to repair the locking system since none lock. Appreciate any feedback so I can lock it in public.

None of the locks work and previous feedback indicates most of the controls originate in the driver's door to start. What are common issues and hence repairs to look for. Thanks.

John

rumb · #2 01-11-2022, 05:46 PM

Are you sure you have vacuum locks? Many models did not.

If you do have vac locks, then yes you have to remove each door panel and test the vac pods and rubber tubes for leaks using a mitivac. The drivers door will have a control switch. Start on that door.
Somewhere on the car is a vac tank. The fittings can leak there also.

Remove black plastic cup behind interior door handle and remove screw and surround
remove 2 screws from C shaped chrome by door latch
unscrew door lock plunger
2 big philips screws hold big door handle on
When removing the door panel use a thin pry and get as close as you can to each pin fastener so you dont rip them out of the cardboard door panel backing.

cth350 · #3 01-11-2022, 05:58 PM

if you don't have one, invest in a small hand held vacuum pump like the mighty-vac and also vacuum caps and a length of vaccuum hose.

Start from the source of the vaccum (intake manifold) and work your way out from there. Replace any little bit of rubber hose if you don't know how old it is. Check individual components for function (holding vacuum and/or moving) as you go. The little cannisters are supposed to be one way check values. They can die stuck open or stuck closed.

Eventually, you'll find a thick yellow line going through the firewall, follow it until you find the line reaching into the door at the hinge. That's the start of lock system. Your mighty vac should let you determine if the system is totally open or not.

There are hose connections under some of the seats, not that I remember where exactly that you can tap into. The big blue service manual has the schematic of the lines.
-CTH

-CTH

jrs3484 · #4 01-13-2022, 10:26 AM

Thanks for the feedback. Short of removing the door cards, how can I tell if the vehicle has the vacuum door locks?

ScooterABC · #5 01-13-2022, 11:03 AM

Quote:

Originally Posted by jrs3484

Thanks for the feedback. Short of removing the door cards, how can I tell if the vehicle has the vacuum door locks?

You can lift up the carpets and see if there are vacuum lines running around, you can probably see the actuator for the fuel lock, possibly for the trunk lock...