Larry: what you have there is a spring seat. The holes you point to are threaded, correct? Look at the bottom of the bottom piece and you will see two holes that line up with the threaded holes in the top piece. Two macine screws come up from the bottom piece and thread into those holes to hold the two pieces together. Once put together they should fit the axle housing and they should barely move on the housing, they should have a slight drag. Then when you line up the axle with the spring seat there is a hole in the bottom center that goes over a dowel that sticks up from the center of the spring, then the U-bolts secure the spring seat to the leaf spring. Pre fit the spring seats (both pieces screwed tightly together) on to the axle housing and if there is too much play you should get an idea of how much has to be taken off so the spring seats will fit with a "slight drag." If they are too loose the use of a file (I used a bastard file as it takes more off) is used on the mating surfaces of both halves to remove the excess metal in order to get to that "slight drag" feel. If you have to file them do it in steps, file a little, put them on the axle, check for play, and so on until you get the slight drag.
I have a '38, HC, and have rebuilt the axle-torque tube, twice within a month, I wasn't pleased with something on the first go around and did it again.
I have extra used screws that hold the spring seat halves together, four of them, if you are interested.
I have extra siightly used (60 miles on them) carrier and pinion bearings if you feel brave enough and crazy enough to rebuild the axle.
The Ring gear is riveted, not bolted, to the carrier, and this was done from '37 '38 and '39 half and three quarter ton trucks, so there is no replacing the ring and pinion gears (easily).
The '37 and '38 axles are the same, the casting number is 377707.
Not exactly a quick reply, however I hope this information helps you.
Later,
Glen
