A couple days ago the ignition key in my 1990 300 SEL started getting sticky. Yesterday it got worse, so last night I decided to stop at my garage that I rent a couple miles away from home and spray some WD40 into it, hoping this would alleviate the situation a bit until I got home and could investigate it further.

The previous time I had started it during the day, it had taken me about a minute to get the key to turn from 0 to 1, so when I tried it again at the garage twice with success, I figured I would be OK long enough to at least get me home, especially with the extra lubrication. Maybe the stickiness would even be gone forever… right? Wrong. After spraying in the lube, the key would not budge off 0. Tried for two hours to jiggle it free, then called a tow truck.

One thing I noticed when I took the key out after the last time it worked correctly was that the door buzzer went on briefly on the way out, and the key slot seemed to kind of slam shut when the key came out and the buzzer stopped. I don't recall the buzzer having worked for a while, so I thought this was odd. When I first got the car about a year ago, one of the first things I replaced was the relay under the dash that turns on the interior lights and key buzzer when the door is open. I'm wondering if that relay (perhaps in conjunction with another switch or relay connected to the shifter to make sure the trans is in P or N) could have anything to do with the key not turning? In trying to research this I read something about a "lock out cable" in one thread, but it was only mentioned in passing regarding removal of the whole switch/lock assembly from the car. What is a "lock out cable" anyhow…?

Anyhow... all of the above is strictly hindsight at this point, because after my and a friend's repeated attempts to jiggle the lock free, including using a clutch drill driver as suggested by one poster here who works at a dealership and insisted it "worked every time", the key is now broken off in the lock and the whole thing feels quite sloppy.

And assuming none of the above were the direct cause, and that the tumbler just froze up, what's the likelihood of successfully drilling/Dremeling out the tumbler assembly and replacing it with another one without dismantling the steering column and dash? I'm quite handy with finesse grinding, back in the day I used to take Lambrettas from 9hp to 32hp with some judicious porting and whatnot. Also, am I correct in assuming that if I successfully get the whole tumbler out, I'll be able to: A) start the car with a screwdriver; B) assess the condition of the switch and steering lock?