I tried using dish soap as a lubricant and can push it in by hand to the point where it just breaks the plane of the top of the bracket. If I push any harder I think the only thing breaking would be my hand. The vice would only get it as far as I got it by hand unless I built some sort of reciever for the bump stop to go into as I closed the vice.
I'm not sure about the u-bolts being long enough but it certainly gives me an idea. I'll try a few things and let everybody know what worked (somethings got to work here). I just hesitate to begin using large amounts of force for fear I will break the bracket or something crazy.
