Doorlock mechanism repair

Written by the backyard hack mechanic Sean750
Document history:
# 13 Dec 2003 added comment
# 23 Nov 2003 initial version

Problem : In my case, the central locking system keeps locking the car when I unlock it. That's mostly related to a stuck servo or doorlock. But all the servo's where working, so at first I thought that was related to a broken doorlock bracket (pin won't go all the way up and down, also not manually with the key) but after the replacement of the doorlock bracket, which fixed the pin problem by the way, the locking problem continued. Sigh. Although less often, but still enough to be pretty annoying.

I've red the comment of MikeNL about lubricating the doorlock. Perhaps the servo has to much resistance when it's trying to unlock. But which doorlock is causing the problem....I deceided to rebuild the driverside doorlock, because the driverside was giving the most problems when manually locking and unlocking the door.

Background: simple, straightforward system. Solid doorlock mechanism, bolted with 3 screws to the door. Window guide rail has to be removed. You don't mess up the doorlock/window alignment with this procedure.

Let's start unbolting and removing parts:
First, remove doorpanel. See section 'doorpanel removal' for details. When you look inside the door, you'll see the following (photo taken from inside door towards the locking mechanism...notice the absolute lack of rust inside this 16 year old car):

It's obvious the mechanism can't be removed without removing the window guide rail. The guide rail can easily be removed, just remove this hex screw behind the door seal (remove door seal partially). Don't be afraid that you mess up the window alignement, that doesn't happen:

And pull the window guide rail slighty to below, now it can be removed:

This is how the window guide rail above is attached. Note that not every galvanized metal is protected against rust for eternity:

I know, three photo's for one silly rail is a bit overflowing... don't forget to disconnect the linkage from the doorbracket to the doorlock mechanism. Now remove these 2 hex screws of the locking mechanism:

And the 3th hex screw behind the door seal, next to the lock. If you don't know them, they are hard to find:

Now you can remove the lock mechanism:

At the workbench, I tried the lock at the point where the linkage of the doorbracket is connected to the lock mechanism. At some point, there was firm resistance:

You can purchase another lock. A brandnew one or one from the scrapheap. I am cheap, so I deceided to take it apart. The mechanism has a plastic cover, which unfortunately is pop-riveted:

I drilled them slightly out, just carefully remove the pop-rivet head only. I used a 7mm drill doing this:

Be carefull not to remove to much material. Addionally, I drilled holes with 3mm diameter and 5mm deep into the remains of the rivets so I can use metal screws with a washer to reattach the cover.:

Removing the plastic cover:

All the grease hardened during a decade of neglect and lots of dirt was sticking to the grease. Notice the pop-rivets, now its clear that you musten't drill to deep:

I can't resist to make a close-up:

I dissolved the old grease thoroughly with degreaser (same stuff to clean brakes) and using a brush, starts already to look better now. Note that no further parts can be removed from the mechanism:

I used a small brush with molybdenum disulphide grease to llubricate it:

The lock immediately started to work better now. Reattached the cover plate, using metal screws. Unfortunately, the head of the upper screw broke, so I just left it this way (with 1 screw):

Reattached the linkages, lock is completed now :

Reinstalling is the same as removing. You don't have to mess with lock adjustment and/or window alignment. Brilliant.

The lock is working much better now. I tried to unlock the car this morning and it didn't lock itself again, so I have some confidence.

Total amount of time : 3~4 hours, depending on skills

Skills needed/difficulty level : The only drawback is that you have to drill to remove the rivet heads, and use some screws to reattach the cover.

Satisfactory level after the job done : I hope that central locking system is working for quite a while now starting from this day, because I am getting so tired of all these kinds of locking problems. I removed the doorpanel for the third time within 3 weeks.....ermmm....has somebody got some spare white door clips for me?

Remark from Sean after a couple of weeks: although the locking improved, I still kept the problem that sometimes the car locked while I unlocked it. After replacing the servo of the doorlock bracket, all central locking problems finally did come to an end.

Story by Sean750.

If you would like to add any comments, remarks and/or corrections to this procedure, feel free to email Mike Oswald and we'll put it on our site. Share your experiences with us so others may benefit from it.