Hey everyone I had new bearings installed on the axles of my 78 spider and reinstalled the right side axle as my manual outlined , but the left side won't go all the way in. Something stops it drop going the last quarter inch. Through the diff. Plug hole I can see the splined end of the shaft is in the side gear and the bearing is halfway in the axle housing flange but something is stopping it from going the last quarter inch. Both axles will go iin the right side. Neither will go all the way in the left....Any ideas?

what style of diff do you have in your car? If it is the earlier type it could be the bearing needs to be pushed in past the o-ring seal??

Look for a burr or obstruction in the housing where the bearing goes.

How hard are you pushing? Have you put a piece of wood against it and beaten it with a hammer?
Some go in easy, some need a little persuasion.

I am with David and would suspect a damaged or out of place O-Ring. It could also be a burr as Csaba notes.

I would refrain from anything but light tapping of the axle to persuade it to go in. All of the load from hammer blows would be taken by the balls in the bearing and the bearing races. Hard “licks” with a hammer can cause small flat places in either surface and result in early bearing failure.

Thanks to everyone for the suggestions. I spent some time buffing and filing the outer edge of the axle housing untill couldn't detect anything like a burr but still couldn't get it to go. Seemed like it was stopping right at the O ring though and I didn't want to do too much sanding there . What I did was put the axle on a bench and place a file on the leading edge of the bearing and rotate the bearing by hand to increase the champher . Made it a little steeper and wider . This let it go in , but it still took some pretty hard blows with a wooden block and a small sledge hammer. Rubber mallet wouldn't cut it like it did for the other side. The old bearing on the trouble side had ceased in the housing and no doubt this had caused some deformation in the housing. Every step of repair seems to expose some other problem , but I'm getting closer to road worthy all the time.