Driver's door inside handle return spring and key lock MALfunction

[Tomnistuff]

I lived with a long term problem of not being able to lock my driver's door with the key, and having to lock it by walking around the car and crawling in the passenger door to use the inside remote lock switch (Mercedes-Benz name or something like that).  The passenger lock worked well with the key, so it was tolerable, if annoying.

When my driver's inside door handle stopped returning to its closed position and just flopped, I did a search on the Pagoda site and found a piece of "gold" in al_lieffring's "Inside door handle spring repair" writeup.

It worked like a charm to fix the "floppy" door handle.  Since the latch was removed to fix the spring, I attacked the "key not locking the door" problem, but two days of experiments and analysis has been fruitless.  I even opened up the passenger door (removed the door panel) and have been trying to compare their functions.

If I just insert the key and try to lock the closed driver's door, the key meets no resistance, and does not lock, but if I push in the button 1/2 way with the key and turn it toward "lock", It turns about half way "45 deg", then stops up against the small V-shaped knob on the latch shaft inside the door that is supposed to unlock the door and will turn no further (for fear of breaking the key). 

Is it possible that the penetration of the striker housing is not quite enough to adequately push in the small mechanism lock-tab at the extreme end of the latch receptacle cavity when the door is closed?

I'll test that tomorrow but beyond that, I am out of ideas.  Any ideas or advice?
Tom Kizer

[ja17]

The door closing mechanism has two positions. The first position is "almost shut". In this position the door lock will not work. The second position is "all the way shut"(position 2) and the lock function should work. Make sure your door reaches position 2. If not loosen the fastening screws on the door cone (on the door post) and move it outward.

[Tomnistuff]

Hi, Joe.
You were right, as usual.
Your comment answered what I was trying to ask in the last line of my post, but you said the answer a lot clearer than I posed the question.   I did what you suggested and managed to find a "striker position" that permitted the key to lock the driver's door.  With the door closed and unlocked, I have to insert the key, push the button half-way in until it hits a hard resistance with the "fully inserted" key, then "bias" the key in the lock direction (It still won't turn.)  Then, while allowing the button to come back out slowly until a slight turning movement of the key is detected.  At that point, I then forcefully turn the key farther to the full lock position.
It is tricky but consistent. 

It feels almost as if the tiny  "lock out" tabs are not pushed far enough into the latch to really permit the key lock mechanism to be free to turn and lock the door.

A closer examination of the striker housing that receives the "cone shaped pin" of the latch revealed that the part of the striker that contacts the little "lock out" tabs has a slot worn into the contact point.  That worn slot is slightly more than a tenth of a millimeter deep.  See the photo.  That certainly can't help the situation.  Thanks for the help.  I'll look for a better striker.
Tom Kizer

[rwmastel]

It looks like that interior part made of a different material could be replaced with proper tools and an impossible to find good replacement part.  Time for a whole new part?