Do Threads of U-Bolt Trailer Suspension Need to be Lubricated When Torqued

Question

Question:

Hi. When installing new leaf springs on boat trailer and new U bolts , do you lubricate the threads on the U bolts before you torque them to spec ? Or do you keep the threads dry ? Thank you

asked by: Dirk

0

Expert Reply:

Hey Dirk, this is a great question but it is not required or recommended to lubricate the threads of trailer suspension u-bolts before torquing them down. Doing so would affect how tight the nut would get.

expert reply by: Jameson C

0

Jameson C.

9/2/2025

Hey Dirk, did you end up installing the new leaf springs and U-bolts without lubricating the threads? I'm curious to know how it worked out for you, as it might help others in a similar situation.

Answer 1

Hello Russ, Welcome to etrailer, I'm glad you found us! Yes, those parts are compatible with each other for a 2" square 3,500 lb axle. The U-Bolt Plate #117594 is specifically designed for a 2" square axle with 1-3/4" or 2"…

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Answer 2

Hello Cole, thanks for reaching out. The 4-Leaf Double-Eye Spring for 3,500-lb Trailer Axles #TRU62FR is 27" long center eye to center eye. I edited a picture to help illustrate.

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Answer 3

Hi Austin, I can help you determine the right replacement double-eye leaf springs for your 2018 Jayco trailer, though we don't have any way of knowing what specific ones you need. It's pretty easy though, as all you need to do is measure your…

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Answer 4

Hey Jason, it's pretty common for replacement leaf springs to be slightly shorter than what they replace as springs tend to stretch/flatten overtime as they wear out so while you are on the right track 3/4 of an inch is a bit too much of a…

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Answer 5

You can use leaf springs that are rated higher than the axle without any issues as long as they measure the correct measurement for your trailer. For example the 6-leaf double eye spring for 7,000 lb axles part #e64SR measures 24-7/8" eye to…

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Answer 6

Excellent question. I had to think about this one for a bit and consult another person familiar with trailer assembly. Normally the band is placed forward of the axle on the trailer but it really does not matter which way the band is oriented.…

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Answer 7

It is possible to mount the springs on top of the axle which is called "flipping the axle". To accomplish this we normally recommend an over-under conversion however there is not one with square u-bolts available for your square axle.…

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Answer 8

Its sounds like you are pretty well on track for what is needed to replace the leaf springs on your trailer. That said, there are two different types of leaf springs; slipper and double eye. If the width of your existing leaf springs are 2" then…

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Answer 9

I would not use any Loctite when installing suspension components on a trailer since the suspension components need to be able to move relatively freely. I would be afraid of getting the thread locker on bolt or something away from the threads. If…

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Answer 10

There should be enough free play in the shackles to allow them to move. There is no specific torque rating for shackle bolts. The first thing you should make sure of is that the bolts you use are long enough so that when installed you will have at…

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Answer 11

Suspension bolts are not designed to be torqued down tightly as this prevents the suspension from being able to move like it needs to be able to do. So the included solution with the kit part #AP233 is the lock nuts of the kit. The nuts have nylock…

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Answer 12

There is no specific torque rating for shackle bolts. You'll want to ensure that the bolts you use are long enough so that when installed you will have at least 2 threads protruding from the nut. Make sure that the bolt you're using has a…

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Do Threads of U-Bolt Trailer Suspension Need to be Lubricated When Torqued

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