Torque for U-Bolts on Trailer Axle

Updated 02/17/2026 | Published 06/12/2024

Question:

I am trying to install ubolts to attach leaf springs to the new axle. All the bolts are stripping at about 40 ft. lbs of torque, below specifications, and on the last 3rd set, the lock washers all sprung open and attached to the nuts. What can I do?

asked by: Mack L

Expert Reply:

Hey Mack, instead of cranking all the way down to the point the bolts strip just go to the point where the lock washer flattens all the way and that will work.

expert reply by: Jameson C

Jameson C.

2/17/2026

Hey Mack, how did things go after tightening the u-bolts just until the lock washers flattened? Your results could really help others trying to secure their leaf springs without stripping the bolts.

Mack B.

2/17/2026

@JamesonC I found out that the problem was that I was lubricating the threads before tightening the bolts. That meant that the threads stripped before the desired foot pound reading was obtained. I learned that you never lubricate threads if you are tightening to a certain foot pound reading.