Help Installing axle shaft.... will NOT seat

[jd_boggs]

An axle seal failed so I'm replacing all seals, bearings and ruined brake shoes.
I removed the bolt and pulled out the steel rod to remove the C-clip. Then removed the C-clip from the diff to pull the axle shaft and begin bearing and seal replacement. After after replacing bearings and seals I lubricated the seals and bearings both. I tried to install the axle shaft but it will NOT fit. It binds up and will not travel the last 3 inches. What am I doing wrong?
I tested bearings and seals for fit on one of the axles shaft because they make 2 different sizes. So I tested for proper fit before installing them.
Is there a special trick get them aligned?
I welcome any suggestions. BTW, it's 1981 K10 4x4

Thanks