Pin Box Loose

[thompsjk]

I have a Momentum 385 and noticed that paint around the bolts on the pin box is worn off and it looks like the pin box is shifting. I then found that two of the bolts were not much more than hand tight. What is the torque spec. for these bolts. They are 5/8" Grade 5 bolts.

Thanks
Jeff

 

[notsosan]

I installed a 5th Airborne pin box on our Reflection. The installation instructions specified 150 Lb/Ft for 5/8" Grade 5 bolts.

 

[Hootie]

We have a 385, (2015) and it the black bag that has all the manuals, we got a master manual for Lippert components. On last page, (107) has general maintenance section which calls out pin box It states110 ft/lbs for torque on mounting bolts. And it also tells you about grease points and so forth. Hope this might help some, Hootie

 

[thompsjk]

According to my engineering hand book 5/8" grade 5 coarse thread bolts has a max torque of 154 foot pounds. It also states that grade 5 as the min for metal to metal structural steel with grade 6 or higher recommended.

 

[Cate&Rob]

According to my engineering hand book.

First thing that occurred to me when I read the question . . . but, mine is in a box somewhere !

Rob

 

[Hootie]

LCI stated 110 in the book. We only use grade 8 bolts at work and use the torque spec the different manufactures give us.( depends on what I am working on) you would think same size bolt would be same torque specs. But every manufacture has there on engineering and they have their on torque specs. I work in the oil/gas industry and work on high pressure equipment and we live by torque specs. do not want to stretch the threads where they will not hold and back out. I did read where You said max torque of 154. Did the book give a +/- ft/lb with the max 154 ft/lbs. I think I would give LCI a call and see for sure what they torque them to,.you never know what their engineering will say. you got me thinking I might have to call now. Hootie

 

[Cate&Rob]

The max torque that the bolt threads can withstand is not necessarily the compression that the joint needs.
Also, painted surfaces or plated bolts will eventually reduce the joint compression and relax the torque from what was originally set. This would cause a manufacturer to spec a higher torque for new parts than what used parts should be torqued to. Whatever you choose to torque these bolts to . . . it is really easy to re-check this. I would do this after the next few trips.

Rob

 

[Hootie]

I got a hold of LCI today and asked about torque values for the pin box on the Momentum385th (Roto Flex) and they gave me the torque spec they recommend. 95 ft/lbs to 110 ft/pound with bolts they are installing with. When I said do not want to stretch the threads above, I was talking about over torque. The reason for torque values and correct compression. Hootie

 

[thompsjk]

Most after market replacement pin box manufacters recommend 135-150 foot pounds. When I have time I will probably change the bolts to a grade 8 and go to 150 foot pounds.

 

[TucsonJim]

The max torque that the bolt threads can withstand is not necessarily the compression that the joint needs.
Also, painted surfaces or plated bolts will eventually reduce the joint compression and relax the torque from what was originally set. This would cause a manufacturer to spec a higher torque for new parts than what used parts should be torqued to. Whatever you choose to torque these bolts to . . . it is really easy to re-check this. I would do this after the next few trips.


Rob

I retired from the missile manufacturing business last year, and proper torque was always a hot topic (pun intended). I'm sure you can imagine that the vibration during missile flight is severe, and proper torque is critical. A typical missile flight is a couple of minutes. However, our rigs are vibrating and flexing mile after mile, day after day. They also see pretty robust temperature fluctuations over time. We got to the point where we'd take a missile at ramdom once a quarter and completely tear it down. During the tear down process, we'd record the torque value on each fastener before we removed it. In most cases, a hard surface torque value would relax 15 to 25 percent! However, if a fastener had been torqued, then subjected to temperature and vibration and retorqued, it would retain it's torque value within five percent. The loose fasteners you found in your pin box sound like typical cases of a fastener losing its torque value over time and then starting to back out. So I'd suggest that once the proper torque value is determined, all owners should check important fasteners from time to time to make sure they have not relaxed. If you check them once after a few hundred miles and a few weeks, they will likely stay at the proper torque value.

 

[Hootie]

X2, once a year at least for me checking the important bolts, besides lug nuts. When I do go to a bigger bolt, I make sure the shear strength is not to high for what I am installing it on, so if it needs to shear it will be able to at proper time, prevents more damage. Hootie

 

[thompsjk]

X2, once a year at least for me checking the important bolts, besides lug nuts. When I do go to a bigger bolt, I make sure the shear strength is not to high for what I am installing it on, so if it needs to shear it will be able to at proper time, prevents more damage. Hootie

I can't really think of a time I would want the bolts to shear. I definitely would not want someone to pull out in front of me, hit them and then be ran over by a 19,000# fifth wheel because the bolts sheared. I would not want to be rearended by a 18 wheeler and have them shear. I can't imagine designing a hitch to shear. Fifth wheel hitches are the only hitches that I know of that don't have safety chains for this very reason. Both of my goose neck trailers have safety chains and you will get a ticket for not having them hooked up. But none of that really matters because knowing what I know about Lippert frames it would fail else where first. Lippert has had numerous frame failures at the pin box. If I was building RVs I would not be using Lippert frames.

 

[huntr70]

If I was building RVs I would not be using Lippert frames.

Lippert builds frames to the spec's of the RV Manufacturers.

Don't point the finger at Lippert, when the Manufacturer's engineers designed inferior frames....

 

[thompsjk]

Most of the welds on Lippert frames look like something a ten year old did. The RV manufacturer specs out the dimensions and GWR. Lippert designs and builds the frame to that. That's why the RV manufacturer does not warranty the frame. The frames are warrantied by Lippert. But the RV manufacturers also hold part of the blame for letting Lippert get by with such poor products by doing business with them.

 

[thompsons 369rl]

Most of the welds on Lippert frames look like something a ten year old did. The RV manufacturer specs out the dimensions and GWR. Lippert designs and builds the frame to that. That's why the RV manufacturer does not warranty the frame. The frames are warrantied by Lippert. But the RV manufacturers also hold part of the blame for letting Lippert get by with such poor products by doing business with them.

Wow, Jeff. You REALLY don't like Lippert, do you? Not only that, but you just offended 10 year olds everywhere. Maybe you should have an RV with someone else's frame. Maybe that will make you feel better and stop spewing negative stuff like this. If Lippert is soooo bad, as you say, show us the numbers.

 

[thompsjk]

I would rather a Leland frame but when Lippert makes the frames for 70-80 percent of RVs that does not leave much to choose from. I do feel that Grand Design has one of the if not the best quality products in their price range regardless of the Lippert frame. The only warranty work that I have had done to my Momentum was a hydraulic hose that had the fitting not crimped properly, guess who made the hose? I personally know two people that have had welds break on Lippert frames. The welds on my Momentum are a lot better than my last fifth wheel but still not great. A little research online will give you a lot of info on Lippert.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/18107981/print/true.cfm

http://www.forestriverforums.com/forums/f29/another-broken-lippert-frame-10934.html

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/20526658.cfm

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/24391034.cfm

This was just a quick few.

 

[Hootie]

What I was referring to in the bolts shearing was if someone put graded bolts higher than was was suppose to be in them.. I have driven 30 + years down I-40 and other roads like most other campers. Seen TV and 5er accidents and seen the pin box and or hitch come loose from trailer and or truck due to the stretching and twisting action and the bolts fractured and broke as designed and truck stayed up right and trailer flipped on side. And I have seen both on side where nothing was going to help, it was going to happen due to circumstances.... point being is the bolts designed to work will work in every day normal use and in extreme cases if they fracture and brake when suppose to you could save people and property. If you put a higher grade in place of what is recommended it might not do it's job and more damage, injury could result. Hootie.

 

[LCBoyer]

Jeff, I think Lippert builds a pretty good frame, at least for the Keystone Montana line

 

[cuttinchief]

I think it's all robots. The Solitude has a great frame because GD spec'd it. Frames are only as good as the designer. That double stacked frame Z of the GD Solitude it's top notch

 

[thompsjk]

I don't think design is bad. I think quality control at Lippert is not great and was also told that very same thing by the mobile RV tech that came out and replaced the bad slide hose on my Momentum. I have been in the oil and gas industry for the past 20 years and spent quit a bit of time in the ship yards working on new facilities being built and have been around a lot of welding? I know what quality welds look like, the welding repairs I do on my farm and the welds on Lippert frames are not quality welds.