E21 door lock removal

Symptoms: key cannot be turned inside the lock.

Goal: remove and reinstall the door lock cylinder.

Performed on: '83 320is

Applies to: All E21 cars: 320i, 320is, 315, 316, 318i, 323i

Disclaimer: I do not assume any responsibility for the correctness of these instructions or their applicability to the specified models. Use at your own risk! Also, use commons sense, don't do stupid things.

Instructions

• Remove the door panel.
• Now decide if you really need to remove the lock cylinder. With the door panel out, you can see the key code that's stamped on the lock cylinder. Actually, you need a little mirror and a flashlight in order to see it without removing anything else. But the point is, if you don't mind spending some money, you can have a key cut based on the code on your lock. It is possible that your old key is worn, but the lock is fine - in which case getting a new key cut to the code will solve the problem. Making a replica of your old key will not solve it because the replica will reflect the same wear. I had a key cut for $40 by a local locksmith, but it didn't solve my problem - in my case, the lock cylinder was bad. Anyway, if you decide you do need to remove the lock cylinder, read on.
• To remove the door lock, you first need to remove the window slide rail, which also happens to have a plate that covers the door lock assembly. The metal part of the slide rail looks like this (just FYI):
  
• First, unscrew the bolt that holds the window slide rail (10mm bolt):
  
• Pull back the rubber part of the window slide rail to allow the metal part to move.
  
• Slide the metal part down and wiggle it loose, then fish it out of the car door.
• Detach the bottom part of the connecting rod that connects the lock cylinder to the lock assembly (you need to detach it from its plastic sleeve (see zoom-in picture of the plastic clip below). Be careful not to break the plastic sleeve. It shouldn't take much force to pull the bottom of the rod straight towards you. I've found it's easiest to do that with a pair of pliers, as shown in the picture below:
  
  
• Leave the top of the connecting rod connected to the lock cylinder for now (and the bottom part just hanging out there).
• There's a horseshoe-shaped metal plate that holds the door lock cylinder to the door sheet metal. It's a square-ish plate with rounded-off corners. Slide that plate towards the front of the car, using a screwdriver or some other rod-like thing as a lever. There's also another smaller, thinner circular metal plate under it that needs to be pulled out around the lock cylinder. (Big thanks to Rob Rhodes [rrhodes] for these two pics)
  
  
• At this point the door lock cylinder can slide out from the outside of the door, with the connecting rod still attached to it (you can fish it out).
• If you need to remove the connecting rod from the cylinder (once it's out of the door), you need to slide it all the way through the plastic hole and take it out from the other end as shown in the pictures.
  
  
  
• If necessary, take a look at my lock cylinder rebuild DIY.
• Reinstallation is the reverse of removal. The circular plate has to be oriented in the right direction, so pay attention to the cuts on the sides. Also, remember that the pointy white plastic part on the back of the lock cylinder, to which the connecting rod attaches, should be pointing towards the rear of the car (when the door is closed).