The Stovebolt Site Forums The Parking Lot Big Bolts 1951 Chevy 4400 U bolts

I changed out the rear spring stack/axle u-bolts on my new to me truck as the originals were severely corroded. I am not sure how much to torque the nuts to though. It seems like I can keep tightening them and while it takes a bit of force, it doesn't seem to get any harder as though something is stretching. Is there a torque spec for these? Or do I just make them good and tight? Thanks for the comments!

Torque values are based on bolt diameters, shackle bolts often have to be taken up until really tight because of slack.

Ed

You should be able to get the torque spec from the mfg of your u bolts. I use an impact and run them down until it can’t turn anymore. But I am doing this on semi trailer u bolts. Also u bolts are supposed to stretch as they are tightened that’s why u aren’t supposed to reuse them. I say if you can still turn them keep on going they will not break.

Torque specs are in the shop manual. My manual is for 1954, but I expect 1951 was the same. For a 4400 (1.5 ton), the spec is 210 to 235 ft-lbs!

Weird, I know I wrote a reply to this a day or two ago but it is not here!
In any case, I did find specs in the manual which I believe were 70/90ft/lbs. Then my mechanic friend said he was taught to tighten them until they ring nicely when struck with a hammer or something. He learned this from a place that specialized in automotive / truck spring replacement.