After reading of the dreaded stuck tumbler/steering lock over the years, and the need for a particle beam blaster or $700 to fix it, I went to start my car and moved the steering wheel ever so slightly as I sidled into the seat. I was treated to the Fort Knox-like sound of the steering lock bolt finding it's mate in the column, ka-lunk!! Having had no tumbler problems, ever, I figured it had just slammed home a little firmer than usual. Two hours later with Lock-Ease, vibrators, prayer and really sore index finger and thumb, I realized the tumbler was NOT going to turn to position #2.

..Remove knee panel(s), steering wheel and instrument cluster with normal methods.
..Loosen (a lot, but don't remove)and slide upwards pinch clamp holding steering lock/tumbler to collar on steering column thru inst. opening. 10 mm. bolt.
..Remove turn signal/multi switch and cruise control stalk from steering column and unplug connectors (3 screws)
..Loosen steering column, two 13 mm. bolts staring at you on bottom of inst. cluster opening.
..Drop steering column a little (~1.5 inches?) and remove steering column plastic fascia (pulls out in one piece towards you)
..Locate the release button on the steering column collar. It will look a lot like the release buttons on vacuum cleaner hoses/attachments. It will be on the wider part of the collar, ~ halfway up, visible from where you removed the column fascia. Of course it won't release since you can't get the key in position #2 (or you wouldn't be doing this!)
.. Try the key once more after praying.
..Use a DIAMOND bit in your Dremel. I used a bit from eBay (30 for $10) and despite the fact everyone swore that this was "space age steel" I drilled the pin out in less than 5 minutes. Use a routering motion. A 30 cent bit! and it was still good when I was done.
..Disconnect the vacuum lines (diesel), warning buzzer lines from bottom of switch, lock out cable (if '89 or newer) from switch. You cannot remove the electrical plug from the back of the tumbler/lsteering lock because you still can't get key to #2.
..Slide the steering lock/tumbler out of the column collar (since you've obliterated the retaining pin with your diamond bit) and fish it thru the bottom, still attached to the electrical cable that you can't remove (yet).
..As per Steve Brotherton, cut the scews for the electrical part of the switch with a carbide disc (3 screws) at the junction of the steering lock/tumbler assy. and the electrical switch portion(aluminum)in the back. It will still be functional, just with slices in the retaining "humps".
.. What I did was push the locking bolt into the assy. with a few choice hammer blows and Viola!...the key worked. The offending pawl in the lock assy. had been released.
..Either way release electrical plug, using screwdriver to get position #2 on the electrical switch if you had to cut, or your key, if the "innards" freed up with the hammer.
..Remove the tumbler at this point if you can rotate key.
..Take the assy. away and put it in a vise and beat on the bolt area some for kicks. There is a aluminum window, peened in four places, opposite the bolt. Remove peens and pry (lustily) the window up only ~1/2". Try key , which should surely turn,remove tumbler.
..If by now the tumbler is still not turning, throw the whole thing away and put in new lock/tumbler assy. You've still saved a ton of money. Assembly is the reverse of before.
..If tumbler is now out, rotate the area behind where the tumbler was until parts start to fall out. This takes alot of tinkering and many will just want to get a new steering lock assy. at this point.
..If you want to continue, remove all of the "innards"(springs, pawls, cams) you can, and pry the window all the way out now.
..The locking bolt will fall thru the window and you'll never have to worry about it again.
..Reassemble assy with the part inside that turns the electrical switch, but leave out the bolt, springs, pawl and cam, and replace the "window" and repeen. Replace tumbler. THIS TAKES A REAL TINKERER TO GET RIGHT, but it is NOT difficult.
..Test the key in the tumbler and you'll see how easy it is to turn. No wonder so many go bad; they are turning a pound of steel in the steering lock with each key turn!
..Take the assy out to the car and spend some time aligning the electrical switch part (key position #2),screw it onto the assy. (with new screws if needed) then put pinch clamp over assy,reconnect electrical plug and fish it upwards and insert into steering column collar. The pinch clamp will hold it in position when tight, even with the retention button being blown away.
..The electrical switch portion will provide rebound for the key from the start position and all will work the same with the exception of no steering lock and no warning buzzer for key left in car. Only now, the tumbler will turn like "buttah".

I took the time to write this up since so many had asked how to disable the steering lock. Most "key won't turn" problems are solved with a new tumbler, but I'm convinced half of these are because the tumbler is so stressed by the locking bolt.

Believe it on not, 3+ hrs. start to finish. You should be an above average DIY and love to "tinker" to do this.

Hope it helps someone.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)