Longer coupler??

As mentioned earlier there is another thread here " bushing or not" all my photos are there but I posted one here to, yes all those components move as one except the inner shafts are actually two d shafts that slide into each other, IF I slide the lower shaft down the bearing will come with it therefore offering no support so the only solution I see here is a longer coupler IF one is made? Hopefully that is a better explanation.

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