84 SD steering lock ignition problem - PeachParts Mercedes-Benz Forum

kerry · #1 03-21-2011, 10:12 PM

With the Landruiser leaking coolant from the radiator my daughter was going to drive us in the SD to get the TD from the storage lot. She gets in and starts the SD. When she attempts to drive away the steering wheel is still locked. I guess I'm having a automotive bad luck day. What's going on? Why is the steering wheel not releasing

kerry · #2 03-21-2011, 11:10 PM

OK, I got the tumbler out. I can turn the lock with a screwdriver but the steering wheel is not releasing. Can someone explain the mechanism so I can try to figure out what is going on. I'm theorizing that there's some kind of pin that goes into the steering column based on Diesel Giant's site and there's no explanation there or picture of how the whole ignition assembly operates the pin. Why is the pin not releasing?

It seems I have the reverse problem from the common one. Typically the key won't turn so the wheel won't unlock, car won't start and tumbler can't be removed. On mine, key turns fine, tumbler comes out but pin still doesn't move.

kerry · #3 03-22-2011, 08:24 AM

I've seen Soothappens pictures in this thread:
http://www.peachparts.com/shopforum/showthread.php?t=283114

I'm thinking the whole steering lock assembly is going to have to be replaced on mine. Is there any way, with the lock cylinder removed, of encouraging the steering column locking bolt to release? I'm assuming that with the column locking bolt in the released position, the pin that the DieselGiant tutorial shows being ground away, can be pushed in to release the whole locking assembly for replacement?

kerry · #4 03-22-2011, 08:59 AM

OK, I found this post:

http://www.peachparts.com/shopforum/showpost.php?p=528822&postcount=11

It describes how to remove the steering wheel locking bolt from the assembly once the whole locking assembly is removed from the car. Seems like a smart move. Can't see it as serving as much of a theft deterrent anymore.
Without having the lock assembly out of my car, it's hard for me to visualize exactly what jbaj007 did to get the bolt out but it seems like a possible solution for me if I get the whole assembly out.

kerry · #5 03-22-2011, 09:15 AM

Here's a description of what must be happening with mine:

http://www.peachparts.com/shopforum/showpost.php?p=2526180&postcount=9

This secondary steering bolt releasing pin is not operating.

kerry · #6 03-22-2011, 09:38 AM

Help me understand this. Am I correct? The steering lock/ignition assembly can be removed with the steering column in place if it is operating correctly by depressing the pin in the nipple/housing which holds the assembly into the steering column? This pin cannot be depressed if the steering column locking bolt is locked because there is some kind of indentation in that bolt which accepts the locking pin when it is pushed downwards? So, if I could get the steering wheel unlocked, the assembly could be removed without dropping the column? I ask this because I'm wondering if it's worth the effort to try to get the steering wheel unlocked before attempting to remove the assembly? If I have to drop the column to remove the assembly anyway, then I'll just do that and get to work grinding away that locking pin.

rs899 · #7 03-22-2011, 11:23 AM

I ran into some of this (not exactly your problem) a few years ago, but the details are fuzzy. I think you are going to have to drop the column IIRC. I can't recall how that hardened locking pin goes- whethr is has to be retracted to pull the mechanism out ( I suspect so). That removal pin is really not obvious.

Not a fun job unless you happen to be <3 feet tall

kerry · #8 03-22-2011, 06:12 PM

TTT again. Bolt is locking the steering wheel. Ignition cylinder is turning with the key and with a screwdriver when the cylinder is removed. Anyone know if there's a way to release the steering wheel lock without removing the whole lock assembly? Does anyone know if the pin which holds the assembly to the column is capable of being depressed with the steering lock engaged if the cylinder is turning?

kerry · #9 03-22-2011, 07:13 PM

And the answer is: The pin will not release. I drilled it out with a 1/4" bit. Took about 3 minutes. The offending part is removed. The locking bolt was not locked in the out position but was just in the out position. It moves freely with the key in position 1 but it doesn't seem to have any tendency to either stay out or in. It seems disconnected from any mechanism inside the lock assembly. Anyone know how that bolt is supposed to operate? Should it suck in tight with the key in position 1? What holds it in? A mechanical connection or a spring?

MS Fowler · #10 03-22-2011, 07:17 PM

Kerry,

Nice running account.
Do you sometimes feel you are talking to yourself?
I appreciate your posting this. I, too, have a SD. I do not have this problem, but I might. Its good to see how you went about repair.
Thanks.

kerry · #11 03-22-2011, 07:45 PM

Quote:

Originally Posted by MS Fowler

Kerry,
Do you sometimes feel you are talking to yourself?

It's a good thing I wasn't drowning.

kerry · #12 03-22-2011, 07:47 PM

Here's the scary thing about this failure. Given the failure mode of the steering wheel locking bolt, I don't see why it wasn't possible for the bolt to come out as a person was driving down the road and lock up the steering wheel. The wheel would have to be in just the right position and a bump or something would have to cause the bolt to move but I certainly don't understand how that couldn't happen.

Yak · #13 03-22-2011, 08:19 PM

Maybe helpful pic here: http://www.peachparts.com/shopforum/showthread.php?t=292859&highlight=wheel&page=2

A part inside the ignition sheared there.

As far as the dangerous failure mode. From what I can see in the cutaway from the W123 ignition column it looks like two things would have to fail to let the lock slide while driving. There's some sort of mechanical connection above the cutaway in the pic (that would have to fail), but it also appears that there's a spring function on the button that should at least lightly engage the "collar" on the pin in the retracted position.

When the pin is retracted from the column it looks like part #10 has just enough protrusion to stop the pin from sliding.

Maybe the spring is old and tired, or maybe part #10 just wore away from friction.

kerry · #14 03-22-2011, 08:27 PM

10 is the locking pin which holds the assembly in the nipple. Yes, I think those failures happened in my case. The bolt moves in and out with little or no resistance in either direction. I can jiggle the assembly in my hand and the bolt goes in and out.

Here's a very realistic scenario. The lock failed when my daughter started the car. The bolt was in the locked position when this happened. Let's say the wheel had been cranked over in one direction when this failure occurred. The wheel would not have been locked. She could have pulled out and started driving. Given the downward angle of the locking assembly, once the wheel got to the point where the bolt could slip into the column and lock it, it would have as the car was driving down the road.

Two additional items for any future readers of this thread:

1. The gauge cluster can be easily pushed out from behind by reaching up under the left side of the dash. No special removal tools required.

2. There is a misunderstanding on various threads on the general topic of stuck keys, locks, and ignition assembly removal. The pin which the dieselgiant tutorial shows being ground out is NOT the bolt which locks the steering wheel and it is NOT made out of hardened steel. It is the pin which holds the ignition assembly into the nipple on the column. Drilling it out does not require a dremel tool, but just a 1/4" bit in a standard drill. It is not difficult and only marginally more time consuming that pushing in the pin to remove the assembly.

The whole process is simple and should only take about an hour, perhaps less.

Remove the driver's kick panel.
Push out the gauge cluster
Unbolt the steering column and let it drop.
Drill out the pin
Remove the ignition assembly

kerry · #15 03-25-2011, 04:20 PM

Got my new lock today. Inspection of the new lock reveals that yes indeed my OE steering lock bolt had broken. They are supposed to be spring loaded to pop out when the key is removed and connected to the turning motion of the key to retreat when the key is turned right. My OE bolt was no longer spring loaded and wasn't attached to the key mechanism anymore. A dangerous failure mode.

By the way, you MUST install a new ignition assembly without the key cylinder installed and then install the cylinder once the ignition assembly is installed in the column. This is because the pin which locks the assembly in the nipple must be depressed in order to install it won't depress unless the key is in the #1 position or removed. It won't fit in as an assembly with the cylinder installed and key in #1 position.