I am getting ready to reinstall my front springs on my 50 F2. The bottom leaf is thick on on end and tapers to thin. This must set the caster on the axle.does the thick end go toward the rear? Thanks

 

I would put the end with the 2 spring clips (the clips that hold the spring leaf packs together) to the front shackle. That is if you are using the factory springs.
As far as the caster goes, I could be wrong but I think that is already built into the axle. If you wish to you could add more by installing shims at the bottom of the spring pack. The fat part of the shim would go to the rear. You would need a longer head spring tie bolt to make sure it gets thru the shim and seats well into the axle. Most folks seem to add about 2 degree shims if they think they need it.
Let's us know how this goes when you are lining up the axle to the spring bolt heads. Do they seem to line up correctly, or is one side off a little bit? Maybe less than an 1/8th of an inch? I had that issue on my 56. Ended up leaving the spring to axle U bolts and shackles loose and one side was lined up and seated but the other side was off from the center by around 1/8th inch. I took a long punch and using the axle U bolt holes, pry against the spring on one side of the axle to get it lined up enough to seat. If I recall correctly one guy here tried rotatating around the shackle bars and shackle pins on the side that didn't line up. It fit great for him, but the grease zerks ended up facing the inside instead of outside. But to me, that wound be a very minor inconvenience as long as it worked.

 

The tapered shim is built into the spring. I checked the manual and they said to put the thick end toward the rear. Thank for responding

 

that is the shim...not a leaf. It has a clearance hole for the center bolt. Probably rusted to the leaves? tap it with a hammer and see if it drops off.
Same here as hooler1, I saw about 1/8" difference in the center to center distance in the center bolts on the axle. I was the guy that reversed shackles on one side. I think stock springs had enough arc it was not a problem. But lowering springs are flatter and not as forgiving. I am convinced Ford built this 1/8" difference to help preload the springs.
Since you have it apart, you could measure the center to center distance of the alignment pin holes in the axle, and compare it to the center to center distance of the springs.

If you are interested, see my post 19 on this link
https://www.ford-trucks.com/forums/1...springs-2.html

 

Thank You fh4ever for chiming in! I wanted to give you credit for talking about your findings and your solution! I just couldn’t remember how far back that thread was. I should of just done a search.

i wasn't sure if I should of went to that next step of what could happen when he tried to bolt his axle back in. But thought to myself that yes, he might run into that same issue. So I thrown that in too.

Thank You again for replying and supplying the link!