U Bolts Torque Value

Depends. What suspension are we dealing with?

 

You can Google that by U-bolt diameter. Yours are probably 7/8's. A 7/8's open end wrench will loosely fit over the bolt. Those torque to around 480 FT LBS off the top of my head.
Most people do not have a torque wrench for that. Buy a torque multiplier or swag it.
One hundred foot LBS is equal to 100 pounds hanging on a one foot long wrench at a 90 degree angle. While that probably does not really help you much a four foot pipe on a ratchet pulled 100 foot pounds works out to around 480 ft lbs. We do not normally use a torque wrench on them but use one to check what we are doing occasionally. They kind of come to a tight spot with four and a half feet of total pull. Stop there and recheck them a month later.
There are exceptions like some Macks with grade 8 u bolts. Rechecking is probably more important than being at the exact torque spec.

 

I’m about to do u-bolts tomorrow as well.

freightliner airliner too.

Now I don’t have to look up torque specs as it already showed up here. Thank you guys.



The U-bolts have come loose and the spring (I think) has dropped or twisted causing the air bag to look crooked.

 

You surely know you have something else going on there. Normally a pin between the axle housing and spring or bracket maintain alignment. You need you look a little deeper while you are working on that.

 

Yes, I’ll be taking it apart to see what’s wrong.

All the other bags are straight and good.

Truck only has 405,000 kms on it.