Drivers side door lock: hard to turn/stiff

[ndelage]

I've got a 92 convertible with central locking. My driver's side door lock requires a lot of force to twist it locked into the 90 degree "double lock" position. So much that I was worried I'd break a key eventually or the lock actuator arm.

I took the lock cylinder out and cleaned & lubed everything. The lock cylinder turns freely now.

But once back in the door, it's still really stiff/hard to turn to 90 degrees (to the right). It seems the locking mechanism is binding up or something. I've sprayed some silicone lube into the door latch mechanism but it still requires quite a bit of force to turn to the double lock position.

I've confirmed this isn't an issue with the door lock cylinder by operating the latch mechanism by hand (by reaching into the door).

Is this just normal? Or is there something I can do to loosen the latching/locking mechanism? I can see the actuator arm on the lock cylinder is getting worn down from the excessive force it takes -- so I figure this can't be normal...

If I need to I can just use my alarm remote to open/close the doors. But I had the door cards off so I figured I'd see if I can fix this. Thanks for any help!

[ibatic1]

I just use my trunk. I've broken 2 keys. 1 in each of my e30s as they both had stubborn locks and that WAS being careful. Also put some thought into keyless entry. It is like 20$ and so easy to install.

[Maddog]

I suggest you either rebuild or replace the lock. My lock eventually froze in the dead bolt position leaving me locked out. Corrosion eventually causing a small spring to fail.

I was able to replace with the same key lock by ordering thru BMW; need registration and DL to order.

[cheffy30]

I just use my trunk. I've broken 2 keys. 1 in each of my e30s as they both had stubborn locks and that WAS being careful. Also put some thought into keyless entry. It is like 20$ and so easy to install.

for what it's worth... I've been using my trunk for years 90 325i sedan.
my drivers lock is stubborn and fragile. i removed it and it needs to be rebuilt. i put it back.
passenger side is a dummy but locking mecanism still works.
access to the locks from inside the door is near impossible unless your arms are toothpicks... due to the fact i have no hole in the door for easy access. total fucking bummer.

[ndelage]

I've taken out the lock and cleaned/lubed everything. The lock mechanism (installed on the outside of the door) feels like it's working great.

I think it's the internal door latching mechanism that's hard to move. (e.g. the combination of the door latch and the other linkage bits inside the door). I'll post a video to better demonstrate what's going on.

[earthwormjim]

Perhaps the linkage to the lock actuator is bent, and can't apply the proper amount of force now?

[ndelage]

Perhaps the linkage to the lock actuator is bent, and can't apply the proper amount of force now?

Good idea, I'll check those linkages. I think the one the connects to the "lock pull" that sticks out of the door (on the inside of the car) was bent, but it didn't seem to be causing any problems. Maybe another one is bent too.

[ndelage]

I checked the linkages and they all look straight. I also re-lubed everything and now the internal door mechanism is smoother than my passenger door (when operated manually from inside the door).

I took a closer look at everything with the lock cylinder installed and I realized it is the lock cylinder that's stiff to turn past 45 degrees (and is making the notching/clicking noise).

I made a video demonstrating what I'm seeing:

https://www.youtube.com/watch?v=AfYW8N3X9_A

You can see that when I turn the key all the way to lock (90 degrees to the right) the spring for the arm kinda pops. So know I wonder if I made a mistaking when I re-assembled the lock cylinder or if this is just totally normal...

[ndelage]

Maybe this is just the normal way the "double/security lock" is engaged?

[MoreMayhem]

Part of the lock cylinder has a small ball bearing whose function I can’t remember, but over time this bearing wears away the surrounding softer metal and no amount of lubricant can fix it. That notchiness you feel is probably this bearing. Later cylinder design uses a roller bearing that should last much longer. I had symptoms almost identical to yours and replacing the lock cylinder fixed it right up. The new cylinder can be made to accept your old key with included parts. Also, other than the small amount of grease that comes with a new lock cylinder, never use any liquid lube on a door lock. It will attract dirt and eventually make the problem worse. Powdered graphite for lock only.

[daleb]

Here's a write-up I did on replacing the door lock cylinder with factory parts

http://www.unofficialbmw.com/e30/interior/door_locks/e30_lock_cylinder_replacement.html