Get some torque on that bolt-






(find the longest black pipe nipple in 1/2" that home depot has)

Then whack the head of the bolt with a hammer to free up the wedge. (Optional)- If you can get the bolt spinning, and can take it all the way out, you might want to remove the locknut and then put the stem back in for leverage on the wedge. I say this because sometimes the lip on the locknut will get in the way of getting a gunked up wedge out easily.

Oh, and PB blaster/liquid wrench/deep creep. Lots and lots.

And the Phrase "kitbashed mongrel" is inspired.