check u bolt torque

[2010augusta]

I know back when I was working as a Jeep and 4x4 mechanic, Whenever we install a new lift-kit or new U-bolts, the customer had to re-tighten or return to the shop to have them re-tightened after a week or about 500 miles, All the metal is trying to stretch and the spring packs settle, so that creates to gaps that appear to loosen the suspension. All the red loc-tite in the world will not stop this from happening, the factory can have this done to spec, and in a week or two it WILL be "loose", the dealers need to check them as part of PDI, but i would not trust that it was done.

My lifted jeep still need to be checked a couple times a year, and it has had the same suspension for 6 years now. I think of the U-bolts as part of routine maintenance.

Additionally, The typical nut used on off-road u-bolts are about 2x as tall as a standard nut, to get more thread engagement, but many of the specs for the truck we lifted were torques of 90-110 foot-pounds, but the axle tubes were all about a 1/2 in. thick steel

 

[watchthebox]

Thanks Jim. That last Q/A answered a question I had had regarding the possible use of Loctite. It didn't seem to me that adding Loctite would help if the root of the problem was stretching of the U-bolt rather than the nut actually coming off. Did the Lippert folks think there was any need to upgrade to a stronger U-bolt?

 

[robnmo]

Just want to thank everyone for this thread............and website in general, I've learned more info than my brain is capable of. We towed our Cyclone from the dealer to home (about 150 miles) maybe an additional 15 mile here for practice backing, etc. I checked the bolts yesterday, some were tight but about half were under torque, some turned at 25 lbs. Thank you everyone, U bolt torque is something I never would have checked. It's on our list of "Interval checks" now hanging in the cabinet door........along with our "Departure Checklist". ;-)

 

[jbeletti]

Re: More of the Same

Ron n Mo,

I'd like copies of your Interval and Departure Checklists to use as seed content for H.O.W. (Heartland Owners Wiki). If you are interested in sharing them, please contact me.

Jim

 

[DW_Gray]

Re: More of the Same

Hmmm..... what do you think about this.

I traveled today after torquing the bolts. I stopped after about 200 miles and found some items had fallen on the floor that never had before. When we got to camp we found some more items had fallen. The roads we drove on today were very good.

Do you think that by torquing the bolts it caused the springs to be a little stiffer?

 

[cookie]

Re: More of the Same

Hmmm..... what do you think about this.



Do you think that by torquing the bolts it caused the springs to be a little stiffer?

No.

Peace
Dave

 

[newbie]

Re: More of the Same

Me neither.

John

 

[caissiel]

Re: More of the Same

I have the Spings on the rear axle bending backward at the axle. I was in Contact with Lippert and they were very interested in my problems and are wiling to replace the bend springs if they are of inferior materials.

So I ordered a complete set of springs and fasteners and will receive it today or tomorrow.

I was further checking the U-Bolts and the damaged springs that are on the axle that the U-Bolts were so loose that I had to turn them up to 2 complete turn at each spring. The way I tighten them is I move them in steps of 10FtLb increments up to around 70.

I have been doing a lot of spring maintemance on my previous trailer, but this is new to me as the springs are not broken and bent back as the pic I have included.
The previous trailer had 5000Lbs Axles and only 4 ply springs. I never bend the plates or U-Bolts retorqued. I use to replace springs at every long trip untill I installed 3 ply units that did not lay flat but keeped its bend shape until a ply did break. Which was not as often as before. My Conclusion at the time was that the short 6" long ply at the bottom was the cause of the springs failing because all failures were in line with the end of this short ply.

From my observation, my springs have not bend down because of weak plies but because of the loose U-Bolts on the rear axle. The bending moment on the center of the spring is at its Max. and the weakest part of the spring is at the center were the 1/2" hole is at.
To Prevent the flexing of the spring in the center the Axle sadle and the U-Bolt/Shock plate has to keep the spring tight. The loosening of my U-Bolts have allowed the spring to loosen up and it bent in the center at the hole location.

When I get the new springs I am going to check the plate for bending, and remove the bottom ply and install them that way as I did to the other unit.
When I get to my town I am going to the local spring shop and have them make thicker plates because I believe we need extra strenght at the axle area. To be able to tighten these U-Bolts properly. I have a hard time to believe that the U-Bolts stretch and the Plate will not bend under the load.

 

[westxsrt10]

Re: More of the Same

Interesting theory on the spring plate. It sure couldn't hurt to have a thicker spring plate made of 3/8".
Is this the rear axle spring that failed? Does your unit sit level when in tow?

 

[lwmcguir]

Re: More of the Same

Your springs are bending due to being overloaded. Your camper may be at the correct weight which means the springs were either to small or made of inferior materials. You need the next heavier size. If these are 3500# then you need 4000#.

I have had many of these in past years before we went to heavy duty slipper springs eventually fail. The heavier plate is good but wont keep the light springs from bending.

 

[caissiel]

Re: More of the Same

I have never been overloaded on these springs, the front ones are ok and the rear were loose at the U-Bolts.
I site level within 1 1/2" at the hitch because I am setup so when I remove the trailer from the truck the trailer sits level.

I torqued the rear springs and they came some,

I have decided that the new ones will go on with the new plates and U-Bolts. I am going to leave the front springs alone and see how they do before changing them all. I feel its the loose springs that caused the extra bending. I am going to keep the old ones for spares after I restore them to spec. at the spring shop.

I have an other theory:
My Flex-Air Equalizers are very tight in the pin, when I raise the front of the trailer they are very noizy, Though the front ones are ok, it could be that the rear axle don't have the chance to follow the holes and take to much load in the bumps. My roads at home are actualy fairly rough. If I cannot loosen the Flex-Air Equilizer I am going to regular Equilizers when I get home for the rough roads.

I though getting a new unit the little problems would end, but I am begining to think that the problems have just got bigger. If I would have put as much work and money on the old trailer I would have a great unit.

 

[jnbhobe]

Re: More of the Same

Mine looked like yours, Lipperet replaced all 4 after the Goshen rally last year. JON

 

[caissiel]

Re: More of the Same

I was told that if they test bad I will get my money back. But I feel its more then spring problems. Its the setup and I feel that just replacing the springs is not enough.

This unit will be our last one and it better last. I had to go through the same problem with the previous unit, until it got dependable. The heavier they get the more we need to look after them.

 

[SilverRhino]

Re: More of the Same

I have never been overloaded on these springs, the front ones are ok and the rear were loose at the U-Bolts.
I site level within 1 1/2" at the hitch because I am setup so when I remove the trailer from the truck the trailer sits level.

I torqued the rear springs and they came some,

I have decided that the new ones will go on with the new plates and U-Bolts. I am going to leave the front springs alone and see how they do before changing them all. I feel its the loose springs that caused the extra bending. I am going to keep the old ones for spares after I restore them to spec. at the spring shop.

I have an other theory:
My Flex-Air Equalizers are very tight in the pin, when I raise the front of the trailer they are very noizy, Though the front ones are ok, it could be that the rear axle don't have the chance to follow the holes and take to much load in the bumps. My roads at home are actualy fairly rough. If I cannot loosen the Flex-Air Equilizer I am going to regular Equilizers when I get home for the rough roads.

I though getting a new unit the little problems would end, but I am begining to think that the problems have just got bigger. If I would have put as much work and money on the old trailer I would have a great unit.

Having been a "wood" worker all my life...issues dealing with metal are not always my strong suit. That being said, what is the rational for having springs that have already failed, re-arced and to possibly be used in the future?? Wouldn't it be safer to just junk them? I thought that once metal was fatigued like that, it loosed strength.

I ask these questions solely for the purpose of learning!

Travel Safe!

 

[caissiel]

Re: torque spec

Springs are made from straight BARS and bend to the proper radius. In my case I feel its a failure due to the U-Bolt and plate installation problem and the springs will be perfect after the centers are redone. Done this many times before on trailer springs. And some spring shops redresses 1/2 ton springs to lift them also. I wound never do that with mild steel due to the steel bending beyound its Yield Point, or breaking point but harder steel has better elasticity.

 

[RollingHome]

Re: More of the Same

Laurent, Thanks for sharing your dilemma, sorry you're having so much trouble. Just the same I am learning from your experience and will get under my unit more often because of your problem/s. Please keep us posted of your progress just in case we too need to do something. That being said, "what if" it is just a defective set of springs ? You know, someone didn't keep them in the furnace long enough to... Have you shown the pics to a spring shop and asked for their opinion and a solution ? By the way, just wondering, what flavor engineer were ya ? Being a newbie the others may know but I don't... I'll venture a guess and say mechanical engineering.

 

[SouthernNights]

Re: More of the Same

This thread goes along with with another very long thread that Larryheadhunter has started.

Laurent, while I respect your your opinion about loose u-bolts causing your spring problems-I disagree with you. I believe there are many factors causing all of our problems (including my trailer) not the least of which may include inferior spring material.
I know for a fact that I am not overloaded ...//heartlandowners.org/showthread.php/11719-3250-weights?highlight=

I also know that my u bolts are properly tourqed and have been since I have had the trailer. It was one of the first things I checked before we ever went out with it and I check them every other trip before we leave.

Loose u bolts will not cause this spring problem but can and will cause many other serious problems, including a sheared off center bolt.
I dont believe the the u bolt plate is heavy enough. I dont believe the u bolts are heavy enough, I dont believe the factory intalled shocks did anything and I absolutley dont believe that the springs are made with the proper steel.

I am having the same problem as you with my springs. They are not quite as bad as yours yet, but they are on their way. The way I see it,there are two choices. Rebuild what I have with new springs, u bolts ,plates and either a wet bolt kit or teflon bushings or go with Mor ryde IS. I thought the Mor Ryde was the way to go, but I am having some doubts-allthough there are a lot of happy MorRyde customers out there. Some of my doubts are strictly financial. Alot of money to spend on a trailer I may not have forever so I am not sure it is worth it. I would rather rebuild what I have and install disc brakes when I do it.

Here is a good article on u bolts ...http://www.eatonsprings.com/ubolttorques.htm

 

[westxsrt10]

Re: More of the Same

Just a thought but if I had a heavy 5th wheel like you guys I'd add a helper spring shock to each wheel. Even the gas charged shocks I added to my Sundance helps supports the unit.

 

[caissiel]

Re: More of the Same

I Did the repairs to the springs for my unit this afternoon.
It was a very good learning experience, that I wish to share in a new post that I will post later when time permits.
Turned out it was not the springs that failed but it was the U-Bolts and the plates.
Lippert was good help in the matther, but they failed to inform me of the possible spring conditions.

It deserves a new post because I was able to learn a lot by it and like to share it with photos.