hi folks, i hope you can give me a tip to get my steering coupling off. after removing the screws i tried prying the halves apart, penetrating oil, tapping it with a hammer, levering it with a small prybar -- nothing so far. i'm reluctant to use fire because of the nearby rubber piece.

the FSM just says "slip steering coupling upwards" as if it were trivial. inspecting one i have on my workbench there seem to be ribs on the shaft side, perpendicular to the splines, which look like they would block such movement. what am i missing?

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'77 240D, 504H, OM617.952, etc.

A steering coupling that uses a pinch bolt 90 * to the shaft needs the split slightly pried apart in order to remove the coupling. ( Like you are spreading apart a top post battery terminal. ) You don't need to bend metal, just wedge something between the ears.

Also, pry on both sides of the shaft at the same time with 2 bars so you are not tilting the joint making it more difficult than it needs to be.

IIRC after removing the hex head screws and using a screwdriver to pry apart the split collars, I used a robust pair of channel lock pliers as my pry bar.

The jaws were around the shaft between the steering box and the lower half of the coupling.
Rocking the pliers back and forth at different steering coupling positions, allowed me to raise the the steering coupling high enough to remove it off the steering box shaft.
(Turning the steering wheel when the front left of the car was supported by a jack stand made it easy to re-position the steering coupling.)

Let me know if you need any help wrenching, I'm free at 5 pm and I have said channel lock pliers in my work toolbox.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

After you've already removed the fasteners securing the steering column to the dash underside , correct?

Because only after doing so will there be enough space/play to allow anything within that system to slide anywhere.

Really? 46-412 goes (1) drain oil, (2) remove oil hoses, (3) unscrew coupling, (4) slide coupling. so no, i haven't unscrewed anything on the other side of the firewall. you are referring to something above the second coupling?

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'77 240D, 504H, OM617.952, etc.

I don't have a 123 in front of me nor do I have a FSM, but my most recent experience with a replacement of a rag-joint coupling was on a 107 car and when doing that car the entire steering column "above" the coupling had to be free in order to slide back/up enough to allow the splined section of the column to clear the female splined section of the coupling. Unless there is some freely telescoping parts of the steering column I think you'd have to make some accommodation for the parts to have some space to move apart.

It sounds like you've unsecured all the fasteners, and did a bit of prying on the pinch clamps, but if there is no linear movement available either below or above the coupling I suspect you can't get any movement enough to get the pieces apart from each other. The steering box isn't going to move so I'd think the steering column above the coupling would need to be freed to move enough to get the splined shaft out of the splined pinch clamp of the coupling.

I could be completely wrong as I'm not intimately familiar with the 123 arraignment off the top of my head, but based on what I have done with this repair in the past, something has to be done to get the space to pull things completely apart. Good luck, I'll be following to see what you figure out and what the problem is.

thank you for the extended comments. i suspect that there is room for the coupling to move in place, up onto the flats of the lower shaft. i tried a series of wedges in the upper coupling joint (the jaw of an open-ended wrench, a nail, screwdriver, etc.) and it did loosen up enough to make a little movement - 1/2" of spline is now exposed. i think i must not have the right kind of wedge -- something that i can really whack into place, but that will not fall out when the shaft is rotated. the nail worked best, but it's hard to reach with the hammer. i think i dropped it on the ground at least ten times.

tomorrow i will try again with some kind of prying fork that can press on both sides of the coupling at once. that could save the trouble of having to constantly rotate it to try another angle. thanks everyone for the tips!

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'77 240D, 504H, OM617.952, etc.

Another thought, try two open end wrenches between the steering box and the lower part of the coupling.
One below to act as a base and provide a fulcrum as close as possible to the lower part of the coupling.

It should increase the mechanical advantage of your two pronged lever (upper open end wrench).

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

good point, alec. i will try out a few combinations of wrenches when i can get back under the hood.

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'77 240D, 504H, OM617.952, etc.

on approximately my fifth visit to the coupling with levers, hammer, and penetrating oil, i got it slid off. no work was required inside the firewall. i put a steel plate between the two sides of the upper half and drove the allen bolt into it to separate them. that seems to have made the difference. damn, was that sticky.

then i dropped the steering box, not quite as carefully as i had hoped, but carefully enough that no harm was done. a length of 4x6 lumber helped. moving forward!

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'77 240D, 504H, OM617.952, etc.