In the text for spring and u-bolt installation in the service manual, it just says "tighten securely", but I just found the torque specs on page 4-48 of the 48-51 Service Manual.
Rear U-bolts: 1/2 ton 75-90 ft lb, 3/4 thru 1-1/2 ton 210-235 ft lb, 2 ton 375-400 ft lb (sure glad I don't have a 2-ton
) I went with 100 ft lb on my 51 3100
Front U-bolts (page 3-13) same on 1/2 ton, 3/4 ton thru 2 ton 125-150 ft lb.
I didn't find shackle bolt torque, but I think 25 ft-lb should do it. Again the service manual says "tighten securely", then says smack the shackle arms with a hammer and retighten.
