Do I Need to Add Washers to the U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles?

Published 08/28/2025

Question:

My leaf springs are under my axle, so the bracket is underneath, and the nuts are on the bottom. Do I need to use a lock washer, or will the provided nuts hold up to vibration?

asked by: Tobey

Leaf Springs Under Axle
(click to enlarge)

Expert Reply:

Hello Tobey,

The U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7" Long U-Bolts # APUBR-8 comes with all the hardware that you need, the (8) 1/2"-20 Hex nuts (12N) will be able to hold up to the vibrations. I do see in some reviews that some people did add washers, but it is not necessary.

What kind of trailer are you working on?

expert reply by: Kate F