I've seen some topics regarding bench seat rebuilds. I pulled details from these forums and other places on the net. I though I would share them with you here in one place.
DISCLAIMER - My bench seat turned out far from perfect. In fact, it looks pretty shabby compared to some I've seen on these forums. However,it began to look better as the leather stretched out in the heat after it was reinstalled.
Here is the finished product (after the leather stretched a bit.
Here is is before the leather stretched out... Kind of disheveled.
Now for the process!
I began by tearing the seat out of the truck and getting it into the garage.
-Here it is with the seat cover. Doesn't look too bad. Let's see what's underneath! ( I also found rolling papers and a beer bottle opener inside of the seat which you can see here. Oh the stories this truck could tell!)
-Here is what was underneath the first seat cover. It looks as if it was put on in the late seventies or 80's. When touched, it turned to dust.
-And underneath that seat cover.. the original vinyl!
Step1: Tear off the original foam and vinyl. I did not do this carefully. Please note where the original hog rings are located and where the original seat cover was attached.
Step2: If you have access to a Mig / Stick welder, weld the springs. I am a terrible welder and my welds broke immediately after the cover was put on the seat

Step3: Put zip ties diagonally and horizontally across weak springs. This will improve support tremendously!
Step4: Attach selected foam with hog rings to create a "muffin top" appearance on the seat. I failed to get pictures of this process. However, I did get a picture of the foam I used. The foam ended up being WAY TOO SOFT. Please put firm foam on your seat. I was broke and used mattress foam. Bad Idea! It's a good idea to separate the seat into two parts before doing this (The actual seat bench and seat back.)
-Step5: Fasten on the cover with hog rings. I got my cover from LMC for about 2 bills. If possible, put the cover in the sun to allow it to be more pliable. I used a hair dryer which was not very effective. After this, put the two seat parts back together. You are done!