Check those Axle U-Bolts

[berridge]

I seem to recall that in a post some time in the past that ubolts with a flat shape on the inner curved surface were available. These were supposed to give better contact with the axle. I'm not sure if these were supposed to improve the resistance to stretching or not. The Dexter site shows only round ones I think. Has anyone replaced their ubolts? I would think to do so would only require supporting the axle under the spring and doing them one at a time.

[richfaa]

I never checked my U bolts and had a axle disaster two years ago. Cost me time, Money and eventually the MoR ryde IS system.

[8e3k0]

Actually as of last fall I added one more long leaf to all my spring packs and changed out my center bolts and u-bolts with long nuts and thick washers to a grade 8 quality. I have checked these new ones a number of times for torque and they have not moved or stretched. Gives me more comfort now when we travel as I don't have to consistently watch in the mirrors to see if the Monty is dog tracking! LOL

[DQDick]

Just got under mine and checked it. Torqued all of them to 60lbs. All of them were less than that several by two or more turns. Monty was bought new in May and doesn't have 800 miles on it.

[luvmywestie]

Checked U-bolts today , only one out of 16 was at the right torque the rest were at about 40 foot pounds they are all now at 65 foot pounds. Thanks for the heads up.

[richfaa]

It would be a good idea to read the dexter manual on the axles for the maint procedure.I did not and paid the price.

[Desert RVer]

Checked our U Bolts after Richfaa had his incident. None were close to 60 lbs and varied all over the place. Our dealer provided us with two different manufacturer's axle manuals. Hedging his bets I guess. A good example of the compentency of our dealer.

[Sheepdog]

At last years fall rally I recall Dexter saying to torque them to 65-70 ft lbs. I set mine at 70 and they have not moved in over 8k miles. Originally I torqued them to 65 when the trailer was new last year and they all moved 1/2 a turn or so to get to 65.

Everyone should check their Ubolts, torque them, and then monitor until they stop moving; and then periodically check to make sure they're all there and in the position they should be.

[Lambchop]

Funny we have to check these U-Bolts. I never had to do this on any trucks or cars in my lifetime.
Yes, I check mine every year & find them loose again! Maybe I will change them out to new grade 8.

Roy

[Ozz]

If a guy would just install another nut and tighten it, they won't come loose... You could also put a lock-washer between the nut for extra insurance.
I'll check mine soon, have that, and the wheel lugs to check before we leave here.

[moutard2]

Jeeze Ozz, yet another simple cost effective solution. You're in a rut!

[Lambchop]

quote:Originally posted by Ozz

If a guy would just install another nut and tighten it, they won't come loose... You could also put a lock-washer between the nut for extra insurance.
I'll check mine soon, have that, and the wheel lugs to check before we leave here.

OZZ, I think the U-Bolts are stretching, that is why the nuts loosen. I think somebody had mention that on a previous post? The U-Bolts need to be a harder material

Roy

[Ozz]

I doubt it, but you never know.

[HamRad]

Roy,
I don't know about needing to be harder material but I do remember a discussion about the U bolts stretching. Because of that if the bolts are ever removed they should not be reinstalled but you should use NEW bolts. I'm basing this on memory and since I often have attacks of CRS you should use this info only after you have found some other authority to verify or deny! I didn't try the SEARCH function since I get so frustrated when using it. Good time to remind folks about checking those bolts. I'll try to remember to do so before our next trip. Happy Trails everyone, Dennis.

[Ozz]

It's the rolling of the threads, not stretching of the materials:

Quality aftermarket u-bolts are made to SAE standard J429 using SAE1541 steel. 1541 provide a 150,00 PSI minimum tensile strength, and 130,000 PSI minimum yield strength and a 120,00 PSI proof load. So stretching, or exceeding the yield is not something one needs to be concerned with.
The reason u-bolts should be replaced after they have been torque is because the threads are rolled, not cut.
Because of this the threads are distorted when torqued. This distortion will not allow the torqued to be maintained when the nuts are loosened then retightened.
Because loose u-bolts are the main cause of broken springs, we suggest that they be re-torqued. While the springs are new and the u-bolts are new, the rest of the suspension is aged and will have wear. It is common that the new parts receive additional stress than the older parts.
Re-torqueing continues to move the nut up to new threads.
Bottom line is we recommend that the u-bolts be replaced once they have been torqued to spec. Whether one does so or not is their choice.
-Mike
Ref:
http://www.eatonsprings.com/atqreinstallingubolts.html

[noneck]

Well, just finished a 266 mile trip with my new shocks, leaf springs, and U bolts. Happy to report all went without incident. Today after work went back under Monty and re torqued;

Shackle nuts all good @ 50 lb-ft

U bolts took a turn but back @ 90 lb-ft

Rig now waiting to go to Dover Raceway end of month.

[pbahlin]

Dexter tech at last year's rally told me that the old U-Bolts can wear at the point of contact between the bottom of the U and the axle. It's a round on round contact point so it doesn't take much movement to wear in a slight flat in the bolt that releases a bit of tension. This is why Dexter now uses a U-Bolt that is flattened at the point of contact. This provides a huge increase in initial contact area that will not wear down as easily. He never mentioned anything about tensile strength change. It was all about wearing down the round bolt from abrasion with the axle.

I replaced mine (the old round ones) with the new flat ones and have now gone 10,000 miles on them with no change in torque. I think they're about $7 each.

Something to think about with a lock nut is that this won't do anything to stop eventual wear. They'll prevent the bolt from loosening up to the point where it will fall off but it won't stop a condition wear a loose bolt gets progressively looser from wear and you won't know it with the lock nut in place.

[bighornram]

GREAT CALL!!

All mine were between 1/2 and full turn loose. I've pulled this new trailer 700 miles.

Thank you

[WeBeFulltime]

This past May when I took our 2008 3400RL to the shop for wet bolt install, they found that all the u-bolt nuts could be removed by HAND! This unit had only been towed 1200 (twelve hundred) miles.

[1Happycamper]

2 or 3 years ago when this topic was first brought up mine were at about 25 lbs. I torqued them to 50lbs and after a camping trip I raised the torque to 70lbs. Since then, every time the torque is checked, it has still been at 70lbs.