The ignition lock on our 1997 318is 4-door has for some time shown some signs that it was wearing out. Sometimes when you turned the key the lock would just spin freely.
Today there was a different problem... the steering lock would not disengage, even if the key was turned past the position where the steering lock disengages.
Although we could get the car running with lots of jiggling of the wheel and the key this needed to be fixed.
First step was to remove the ignition lock or "tumbler". There are plenty of how-to's for this job, but this video on Youtube is one of the better ones. There is a little advice I can add that will make this a whole lot easier. The tool of the choice for this job is a bobby pin, but if you put it too far it won't work, and if you put it in not far enough it also won't work. It has to be just right. To make sure it's just right bend your bobby pin at the 27mm mark (see my illustration below). Then it will be the perfect depth. And make sure you turn the key to around position 2.
Once the tumbler was out I couldn't see anything wrong and my attempts to clean and lubricate didn't seem to be helping. In fact it was worse.
Wanting a quick but safe fix so my wife could use the car the next day I found articles online talking about deleting the steering lock. This article seemed to be the most informative. I decided to give this a go after reading more stories of people who's steering locks had come on while driving and nearly resulted in disaster.
So I drilled a big hole in the centre of the area illustrated in that article and amazingly it was in the exact right spot and right diameter for the spring to literally fall out completely undamaged. The result was no steering lock just as promised. However, I was concerned that by just pushing the little exposed locking pin up the steering lock would engage although it disengaged with a little wiggling of the wheel.
For safety I decided to use some hot glue to attempt to seal the hole and stop the locking pin from moving. I cleaned the area first with alcohol and then gently filled it with glue being careful not to put any pressure on the locking pin and engage the steering lock. It seemed successful although I will probably never know if the pin is actually stuck in place.
I still have to fix the spinning lock issue which should be fixed by replacing the tumbler, but can also be solved by a carefully placed hole and screw to lock it in place.
Update: just an extra few comments on the tool to remove the ignition tumbler. I tried sticking all sorts of pins, paperclips, allen keys, drill bits and coat hanger wire down there but it is not about the diameter of the wire. The trick is that you need the end of whatever you use bent a little so when you turn the wire it acts as a lever to push the locking mechanism in to the right position to remove the tumbler. So use a bobby pin or paperclip, bend the last few millimeters out a little, and bend it at 90 degrees at the 27mm point, just like my picture. Then insert it parallel with the key in position number two and turn it slightly clockwise. Good luck.