This is something that seems to come up fairly regularly,and the response is always "get a bentley" or "search." And, if you search, all the results say "get a bentley."
Well, I have a Bentley, and frankly their description on how to do this sucks. It gives basic info and a very vaguely drawn "technical" drawing that you are instructed to follow. A rare miss as far as the manual is concerned.
Anyway, I am currently swapping a 1987 gti to ce2 wiring, and thus have to swap the ignition housing to use the ce2 style turn signal stalks, but wanted to keep the same key. So, it was necessary to get the original lock tumbler out of the ce1 ignition housing and put it in the ce2 one that I got from the yard.
-1/8" drill bit
-Awl, or some sort of pointy device to push the retaining spring down
-Vice is pretty useful
First get the ignition housing out of your car, if you have trouble doing that, you may not want to attempt the rest of this Now pull off the black plastic surround by the key hole. It'll probably break, or, at least, mine did.
Looking at the top of the housing (the top has two mounting screw holes for the turn signal stalks), find the end of the collar that goes halfway around the housing. Now, look for a seam line from where the piece was molded together.
(picture was taken after I had the tumbler out)
You want to find the point that is exactly half way between these two landmarks and draw or scribe a line here. This is going to be one of the dimensions you need to find out where to drill your hole.
Now, you need to find the next dimension. This one is a bit easier, because it is about ~1/2" in from the edge of the housing. Measure from the edge of the housing, not the edge of the lock tumbler (it sticks out beyond the housing).
(again, lock tumbler is already out in this pic., red dot is where you want to drill, ignore my scribed line, I estimated wrong on my first try )
Now that you have your point marked, it's time to drill a hole. Use a 1/8" bit and go slowly. The metal you are drilling through is only about 1/8" thick and drills very easily (aluminum maybe?). If you drill too far, you will destroy your lock cylinder.
When you feel the drill break through, stop and look in. You should be able to see a piece of steel inside the hole, this is the retaining clip.
This clip fits into a small recessed area insde the ignition housing.
Once you've spotted the retaining clip inside the hole, get your awl or whatever pointly implement you are going to use and push in the hole against the retaining clip. As you are doing this, pull out on the tumbler. With any luck, it will pull out of the housing while you hold down the clip.
This took me two tries to get right. The first housing I used got destroyed. I then used a cutoff wheel to disect it and figure out how to do it so I wouldn't ruin my good lock cylinder. I'm not responsible if you mess up your car of hurt yourself in the process. Good luck.
fixed some typos
Modified by s-rocc at 10:42 AM 3-5-2009