1/2"? I thought they lined right up. Does it measure 40" between the centers of the spring pads?

 

Allow me to reword all this mess I made.

open diff: the one wheel wonder
limited slip: one wheel spins and when it loses traction it transfers over to the other wheel. has clutch packs, and a friction modifier lube.
locker: Detroit is a common one. It allows both rear wheels to spin at the same time constantly. You'll hear a chirp when rounding corners....some more modern ones allow the diff to seperate when turning corners.
spool: this is the full time both wheels spin. welded spider gears are called a "Lincoln Locker"

posi is a chevy term for limited slip, AFAIK.

detroits and spools were never offered in trucks.

 

Yes the pads are 40" to the center. I just thought of something. When I rebuilt the bushings in the rear springs and put the hangers back on I didn't tighten them all the down.(I was waiting to repaint them and lock-tite the bolts) My 12 year old son measured the springs for me and said "about" 40 and 3/4". But I just asked him how he measured and he said outside of the bolt to outside of the other bolt. So once I tighten them all the way down it should be right. See I told y'all I'm still learning.

 

In our racecars we would weld the spider gears to make a posi.

 

I just finished cleaning and painting the rearend. I put in new axle seals. Went to put the rearend in and it is still about 1/2" off from dropping on the pins. Everything is tight. I went and measured the pads on the old rearend and the pin-hole in the pads are 40 1/2" apart. I know the rearend had been changed before several times, but the springs were not changed according to the p.o. Should the pin on the springs be at 40 or 40 1/2? By the way it is '50 f-1.

 

If the perches are original IE riveted on, then is it possible they bent outward? I've used a come-along to suck in the pads on a 70's f150 before, maybe that will do it?

 

Yea I ground the rivets out when I was stripping the frame. I took everything off the frame, sandblasted it and put it back together. I tried a racket strap to pull the springs together, but it was making the driver's side spring twist a little more than what looked safe.