W108 Ignition Removal

[w1083]

I have a 1972 280SE W108. Recently, when I put the key in the ignition, it doesn't want to turn passed the #1 position unless I keep trying to wiggle the key back and forth to try and turn the car on while moving the steering wheel side to side (it has the automatic steering wheel lock). I'm guessing the tumbler inside the ignition has gone bad? The key is a fairly new key cut by the Mercedes Benz Classic Center.

I've never removed the key ignition from the car before. Has anyone done this that can let me know how to do it start to finish? I've read that the instrument cluster has to come out but others haven't had to do that. Is there anyway to access it from the back through the radio opening? I've replaced my hazard light relay that way so I'm hoping I can remove the ignition the same way? I dread removing the cluster as everything works as it should and want to avoid breaking anything that connects behind it, etc.

[aluminum]

I am going to Let other Chime in But The Instrument Cluster is not all that hard to remove
Evan with big hands you can reach in from under the dash right side of steering wheel and upward . You well finally feel a plastic Knob about Quarter Size and turn it counter clockwise until undone . Now you can pull the Cluster forward a Bit . At this point you can undo the Spedo Cable and pull the cluster part way out . You don't need to remove it all the way as I remember to remove the Ignition switch but here I well let someone chime in as to the exact removal at this point . ( you may be able to just remove the back part of the switch and change that )
i this helps . The switch fits from a bunch of Mercedes as well if you get one from salvage . perhaps someone has a list of what cars interchange the switch

[w1083]

So what I've noticed is if I leave my steering wheel turned and not straight when I turn the car off, I don't have a problem turning the key over to start the car. But if I leave the steering wheel straight and automatically locks when I turn the car off, that's when it's hard to get passed the Number 1 position.

Any ideas what could be causing this issue?

[ScooterABC]

So if this is only a problem when the steering lock is engaged, I'm wondering if it's sticky or if there is a lot of tension on the lock when it's engaged. Try this... Turn the steering wheel the opposite direction from whatever direction it is under tension and see if the key just works easily that way. I don't think jiggling the key is what is making it work, I think it's relaxing the tension on the steering lock. If this is the case, I think it might be as designed. UNLESS this just started doing this. Has it always been this way?

[w1083]

The key will turn over and start the car fine if the steering wheel is turned a good amount when the car is off so that the steering isn’t locked (seems to only lock when the wheels are straight). But if I leave the wheel straight and turn the car off, the steering is locked and I can’t turn the key passed the Number 1 position. This symptom is new and just started happening.

Before this, I would simply just turn the steering wheel slightly to unlock the steering while turning the key and it would unlock the steering wheel and turn over like it normally has the last 7yrs.

[aluminum]

This is a common Problem you need to replace the Ignition Switch . Not sure But I think you need to Pull the Instrument Cluster Part way Back out of the dash in order to remove the switch . Perhaps someone can give exact instructions I hope better then I

[w1083]

So I've gotten the white knurled nut off the back of the cluster from underneath but now the cluster won't even come out enough for me to see the back of it. do I need to undo the speedo cable from underneath? I also have a tach so I'm not sure if anything from that is keeping me from being able to pull the cluster out more.

[aluminum]

Originally Posted by w1083

So I've gotten the white knurled nut off the back of the cluster from underneath but now the cluster won't even come out enough for me to see the back of it. do I need to undo the speedo cable from underneath? I also have a tach so I'm not sure if anything from that is keeping me from being able to pull the cluster out more.

Yes you now need to Undo the Spedo Cable the same way you removed the Plastic Knob . Just turn it counter clockwise under the dash and the cluster well pull about Half way out . To completely remove ( I don't think that's necessary ) you half to remove the Oil Pressure line



The Spedo Cable where you Un Screw it is smaller then the plastic Knob but it is Knurled Metal right in the back of the Spedo itself . it is about 1/2 the size of the Plastic Knob you already removed . Most often it is a bit tight but still only Hand tight most of the time . If it well not turn try moving the cable about as you turn counter clockwise and it should brake free



Once that is done you should be able to pull the cluster about half way out . Then you must search for a Bolt that well remove the entire Ignition switch . You may be able to just remove the back part of the Ignition switch Via 2 screws as I remember ( requires a small 90 degree ratchet drive screwdriver ) . This is most often the part that has gone bad . Last one I changed I removed from a diesel 240 and installed in a 450 MB . same switch like $5 / $10 at salvage yard

[w1083]

Originally Posted by aluminum

Yes you now need to Undo the Spedo Cable the same way you removed the Plastic Knob . Just turn it counter clockwise under the dash and the cluster well pull about Half way out . To completely remove ( I don't think that's necessary ) you half to remove the Oil Pressure line



The Spedo Cable where you Un Screw it is smaller then the plastic Knob but it is Knurled Metal right in the back of the Spedo itself . it is about 1/2 the size of the Plastic Knob you already removed . Most often it is a bit tight but still only Hand tight most of the time . If it well not turn try moving the cable about as you turn counter clockwise and it should brake free



Once that is done you should be able to pull the cluster about half way out . Then you must search for a Bolt that well remove the entire Ignition switch . You may be able to just remove the back part of the Ignition switch Via 2 screws as I remember ( requires a small 90 degree ratchet drive screwdriver ) . This is most often the part that has gone bad . Last one I changed I removed from a diesel 240 and installed in a 450 MB . same switch like $5 / $10 at salvage yard

Thank you! I finished the job this weekend and all is well.

[aluminum]

Originally Posted by w1083

Thank you! I finished the job this weekend and all is well.

Been a long time since I have done that >. Just where is the Bolt as I remember you must remove to get the Lock / Ignition switch out .


Or did you just unscrew the back of the Ignition switch and just change that part only



I remember its hard to find or the like ?



Thanks Glad I was able to help

[w1083]

Originally Posted by aluminum

Been a long time since I have done that >. Just where is the Bolt as I remember you must remove to get the Lock / Ignition switch out .


Or did you just unscrew the back of the Ignition switch and just change that part only



I remember its hard to find or the like ?



Thanks Glad I was able to help

The hardest thing for me to do was get to the knurled nut behind the cluster and disconnect the speedo cable from behind and under the dash since I didn't have much room to disconnect it when pulling the cluster out towards me. And I didn't have to remove the temp or oil pressure lines either which I was worried about. Putting both of those back was a pain as well, haha. I also replaced the ignition switch with a new OEM one for preventative maintenance.

The 10mm bolt is on small round bracket that holds steering lock and threads from behind which I was able to loosen with a regular small ratchet. Once removing the 10mm bolt, I unplugged the ignition switch harness from the ignition switch on steering the lock and used a small mirror (similar to what a dentist uses) to see the small pin that needs to get pressed in order for the steering lock to slide out from the round bracket that holds it. I also had to disconnect the black plug from the steering lock for the open door buzzer.

Thanks again for all your help!