ignition lock disassemble

[jimfulco]

Anybody know how to take apart an early GM column mounted ignition lock? Not how to R&R the thing, but how to get inside the cylinder itself. I want to shuffle the little wafers around so I can make a key that's removable in all positions.

[Titomars]

They are not meant to be opened up there is a press fit then swagged collar on the end where it engages with the sector gear. Usually trying to remove that collar breaks it. Also getting it back on is another can of worms. it has to be on tight since the collar is also the cylinder stop.
Assuming you can get it apart you would not need to shuffle the tumblers around. You would need to cut a groove in the inside of the outer case corresponding to the "on" position or which ever position you wanted it removable. the groove would allow the tumblers to move as the key is withdrawn. The reason the key is locked in is the tumblers have no way to raise and lower as the key is withdrawn

[jimfulco]

The collar comes off and goes back on OK. I just don't know how to get inside.

What I want to do is to change the key so that the cuts get deeper toward the tip, and the little "between-the-cuts" peaks are smoothed off. That way, when I pull on the key, the tumblers won't have to move to let it out.

[Titomars]

Originally Posted by jimfulco

The collar comes off and goes back on OK. I just don't know how to get inside.

What I want to do is to change the key so that the cuts get deeper toward the tip, and the little "between-the-cuts" peaks are smoothed off. That way, when I pull on the key, the tumblers won't have to move to let it out.

I get what you are trying to do. I just would not want to rekey my entire truck to do what your doing. ohh wait you probably have dual keyed truck.
its been 30+ years since I opened one up. If I remember correctly once the collar is off you have the key in the cylinder and the off position the cylinder should slide out of the case.

[Liberty]

Originally Posted by Titomars

I get what you are trying to do. I just would not want to rekey my entire truck to do what your doing. ohh wait you probably have dual keyed truck.
its been 30+ years since I opened one up. If I remember correctly once the collar is off you have the key in the cylinder and the off position the cylinder should slide out of the case.

You know, that actually sounds familiar. I think you are right.

[jimfulco]

Well I poked around on it for a while and finally got it apart. The tumbler retainer looks to be a thin piece of stamped metal that's staked to the plug. I can't deal with tiny staked things, so to the locksmith it goes.

I hope they keep the guy who designed that thing in a cage somewhere. Under the bezel, there's a washer. Under that, there are 2 small brass plungers in the right-hand edge of the cylinder housing that act as detents for the LOCK position. The uppermost of the 2 also blocks a nub on the plug from turning counter-clockwise past the ACC position. Depress that plunger and turn the plug (key all the way in) a fraction of an inch more so the sidebar* on the plug lines up with a 1/8"x3/8" slot on the right end of the housing. The nub will be above the plunger. Pull the key out a notch or two to disengage the key buzzer mechanism. The plug should now come out with the proper amount of wiggling, jiggling, and kind words. No small parts came flying out, so working inside the two-gallon ziploc bag wasn't necessary.

* The sidebar is gray metal with a brass cross-piece on both ends, but you'll only be able to see one end at this point.

[Liberty]

Well, you could always break it I suppose. The cylinders cannot be opened.
I'd just find a junker cylinder that doesn't hold the key in anymore