After replacing the factory front drive shaft with a Superlift C/V shaft I couldn't get the factory dust boot back on the new drive shaft. It seems the new shaft has a smaller diameter collar than the stock one and the boot won't stay on. Is it very important to have a tight seal on the boot, and if so what can you recommend to fix it?

Zip-tie!

X2

It won't zip tie. There is about a 1/4" gap between the boot and shaft. If I try to zip tie it it just binds. As it sits the boot is pressed against the shaft flange with nothing holding ita nd secured tightly to the case side. I just want to know how important it is that the boot be tight.

if i read correctly, the reason for the boot is to keep out water and dirt
because that is where the shaft slides in and out.
if you are concerned about it then wrap some duct tape around the shaft to build up the gap, then zippie it. once it is tight you get a razor knife and cut off the excess tape so it don't show. kinda redneck but i have done this on several different applications. hope this helps.
p.s. i like some of the redneck cures,some shouldnt have the redneck stamp cause they are pretty good.