Steering Coupling Removal

[Tom in seattle]

I need to replace the bushings in the steering coupling of my 250sl.  I have read the description of the power steering in the Tech Manual and have slid the shield up the steering column, removed the two allen head bolts from the coupling.  Now I'm stumped. The coupling and splined shafts coming into the coupling are rusty and I am having difficulty getting the coupling to slide up or down on the splined shafts.  Ive generously sprayed PB Blaster on the coupling and have tried prying one half of the coupling apart from the other but with no success.  I need some suggestions on how to remove the coupling.  Thanks

[ja17]

Try jiggling the steering wheel to loosen up the splined coupling. You can also use a heavy screw driver to slightly pry at the cut. Do not over do it.

[getsmart]

Bit hard to explain without a diagram but similar to what Joe stated but with a screwdriver you might damage the spline. I recently installed my steering column and had to take it out again. The coupling will not easily release if you can't evenly spread it open. It only needs to open a mm or 2 and it will release easily. Try making a very small steel wedge that you can tap into the coupling opening to spread it open but not so big or deeply that it touches or damages the spline.

Rgds, Joe

[Tom in seattle]

Thanks I will give that a try.

[getsmart]

Thanks I will give that a try.

Good luck Tom, yell it if you need me take photos or anything

[Harry]

On a related note, I wonder if it is possible to disengage the steering column coupling from the steering box coupling by sliding it up the column, then spread it open enough to rotate it slightly around the steering column?  As I recall, that coupling looked like it was cast and probably wouldn't open that far without cracking.
I need to clock the steering column just a bit to get the turn signals cancelling properly.

Thoughts?
Harry

[Tom in seattle]

Harry, yes the steering coupling is cast.  I read in notes to the section in the tech manual that it is possible to take 3 bolts out of the steering box.  I think this will allow the box to separate  the steering coupling into two pieces and allow the bushings to be inserted.  Also does not require re-indexing alignment of the steering shaft.  Have you tried this method or know of its risks?

[afibbe]

I just reinstalled the steering column and gear box last Saturday. The coupler is robust and can take some pulling and pushing. The bolts that go into the coupler and hold the shaft in place must be removed completely before the shaft will come out of the coupler.

When you reassemble, I strongly recommend that you put the centering bolt in the steering box. The details are in this forum. This locks the gear box in the center position. I then put the steering column loosely in place and connected the key cylinder assembly to the column. Next I used the key cylinder to lock the column in the center position. I put the coupler on the end of the gear box them wiggled, pulled and pushed until on the column until it slid into the coupler. Now both are in proper alignment

The key to making this process work is cleaning the parts. I used dental picks wire brushes to remove all the stuff in the splines. When I assembled I used a little bit of Lithium grease.

I hope this helps
 

[Harry]

Thanks all - very much!

Harry

[Tom in seattle]

I have now completed my rebushing  the steering coupler.  If this is the last task I have to do on my back across the door opening with a light and mirror in hand while searching my brain to adapt existing tools to perform the job, it will be too soon.  What a terrible venture.  I appreciate the advice.thank you.

Separating the two halves of the coupler on the two splined shafts was a real challenge.  I dosed it with penetrating oil for a week as necessary.  I removed the bolts on the clamps and started by driving a wedge between the two halves eventually allowing one half down the steering pump spline and the other up the steering column shaft.  That allowed me to get the two pins out of the lower half and then was able to pick what was left of the lower bushing out of the coupling half.  To insert the new bushings I started be grinding a very small bevel onto each bushing and came up with a rod used to slide the upper half down while putting a wedge between the steering box and the lower half.  This process did not require separating either half of the coupling from its shaft and eliminated a need to measure or change the shaft alignment or turn signal geometry.  You will want to remove the steering wheel to create room for you in the foot well.  Repositioning the steering wheel is no challenge.

End result is no play in the steering and a promise to never do the job again.  Being nearly 80 doesn’t help!  This again proves the irreplaceable value of this website.

[Harry]

Tom,

Thanks for the follow-up.  For what it's worth, almost anytime I have to be under the dash, especially doing this type of work, I remove the seat and stack towels where the seat was.  With the seat in, it's just too much for my back and this really does make it much easier.  Removing the seat is a pain but I find that it's worth it.

Harry

[ja17]

Interesting technique, leaving the metal parts in place and just replacing the bushings. The later MB cars did not have replaceable bushings and the whole coupler had to be replaced.

[stickandrudderman]

The steering box is only held in by three bolts.
Remove the bolts and the box can be moved sufficiently such that there is enough clearance to remove the coupling and overhaul it on the bench.

[ja17]

Stick, yours is the technique I usually use.

[EeVeeWee]

Hopefully these pictures can help.