After 6 months of driving my 91 300SE, I just noticed that I can open the right rear door from the outside when the lock button is down. I looked through the CD manual, but I couldn't find a section with specifics on the cranks and levers to help me figure out what's going on. Any advice on how to procede?

Also, the right front door seems to have a non-standard lock mechanism. I can't turn the key counterclockwise from the outside to lock the car (even with the door closed), but I can push down on the lock button with the door open to engage the central locking feature. No other W126 I've seen is this way.

Thanks is advance.

Regards,
Sixto
78 450SEL
91 300SE

Sounds like you might have a problem with the lock on the passenger side door. If all other doors are closed, and the engine is not running then the pushing down on the passenger side lock should lock all the doors, if any other door is open it will not lock when you do this, and if the engine is on only the drivers side door lock will lock all of the locks, and only if the driver's door is closed (it will not lock if the driver's door is open). Hopefully your problem with the key lock is not serious. You might try putting some graphite (found at any hardware store) in it to lubricate it, that just might just loosen it up.

The tip is much appreciated. I really *really* feel that the front passenger door lock mechanism isn't standard issue. I can engage the central locking system by pushing the button down whether the front passenger door is open or closed. Faulty is one thing, but it seems to do things that a standard lock can't be made to do. I only do this with the engine off. The driver's side works as it should per the manual.

I also feel that there is a physical barrier in the key hole preventing locking the door. It's nowhere near freezing in this area. The resistance doesn't feel like friction, it feels like a brick wall.

Regards,
Sixto

As far as being able to open the rear door, even when the lock button is down, check the long linkage rod that runs from the inside handle to the latch. you will have to pull the door panel to get at this. I had a similar problem on my driver's door. Even with the door "locked", I could open the door from the outside by simply pushing the thumb button.

I found that the rod end had slightly bent beyond 90 degrees. The ends of the rod are bent at 90 to engage the mechanisms, having one bent a tad too far throws the works out of synch, The door will appear locked, but the lock hasn't engaged. Although, it just dawned on me that this may not apply to rear doors, as they should also be equipped with a spring joint for the rear child proof system.

But still worth a look.