Half shaft won’t go in all the way, or am I being daft?

[Telemuhcaster]

Hello all, just starting to rebuild front axle. Put new seal and bearing in ball. Now I can't seem to get the half shaft in enough to get the stub axle on. Am I missing something?
Replacement bearing is the same size. Does something I'm not seeing not lining up. And yes before you ask it is engaging in the splines in the diff. It's only about 1/4 inch proud of the face of the swivel pin housing!

My question is, am I being daft here?

[diffwhine]

Did you replace the half shaft bearing in the swivel housing? If so, did you also change its bearing seat and collar on the half shaft? They do vary in size...

[jkhackney]

I can't think of any component in the assembly that's approx 1/4" that could be in the wrong place. I wonder if it's hydraulic resistance with the oil sealing up the tight-fitting splines? You can see the diff splines with a good light. Is there maybe some grit in there? Or a glob of solidified EP90 or grease? Is the halfshaft seal flush with the axle end with the sealing lip toward the diff? I know it's heavy and slippery but have you wriggled the halfshaft up/down and side/side by grasping the UJ as you push it in? I find it easiest to lock the opposite front hub and the propshaft when I re-fit a halfshaft.

Jeremy