Coast Resorts Open Roads Forum: Tech Issues: Does this frame cross-member break matter?

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Topic: Does this frame cross-member break matter?

Posted By: joebedford on 05/27/17 02:27pm

Yes, I suppose it matters. I was chasing a plumbing issue and discovered this when I opened up the underbelly of the rig. At first I thought it was one of the black tank supports but on closer inspection it appears to be a cross-member. It is a steel bar at the top and bottom with zig-zag rod welded back and forth.

It's in a very bad position near the tanks and water lines. Welding would be problematic to say the least. I wonder if a steel L with bolts would be sturdy enough?

Posted By: joebedford on 05/27/17 02:43pm

I don't know if this makes the break any clearer. This is looking straight up. The broken piece is L-shaped and is broken on both vertical and horizontal planes. The RV frame is to the left in this photo. I think the grey thing to the right is a grey tank resting on this piece..

Posted By: joebedford on 05/27/17 02:51pm

There's clearly a notch in this piece. I'm wondering if the horizontal piece should have gone on top of the main frame flange and the vertical piece below. Why else would the notch be there?

Posted By: kerrlakeRoo on 05/27/17 03:31pm

Is the part where the crack is located an active support for the box above, or for the tank? Or cant you tell?
Either way, I think I would empty the tanks and very gently take the unit to a good local welder. If it appears that stress cause the break I would ask the welder how best to provide some additional support.

Posted By: Redwoodcamper on 05/27/17 04:27pm

Doesn't take much space to get a mig gun or a rod up there. The annoying part is prepping the area. I'd check your other supports as well.

2011 ram 3500. Cummins 68rfe. EFI live. 276k miles and climbing.
2017 keystone bullet 204

Posted By: rhagfo on 05/27/17 11:20pm

I would get it fixed asap.

Russ & Paula the Beagle Belle.
2016 Ram Laramie 3500 Aisin DRW 4X4 Long bed.
2005 Copper Canyon 293 FWSLS, 32' GVWR 12,360#

"Visit and Enjoy Oregon State Parks"

Posted By: fj12ryder on 05/28/17 07:42am

Seems to me most places that used to be attached, and now aren't, should be repaired.

Howard and Peggy

"Don't Panic"

Posted By: phillyg on 05/28/17 09:04am

Can't tell much from the photos but if you've determined it's part of the over all frame structure, then yes, should be repaired.

--2005 Ford F350 Lariat Crewcab 6.0, 4x4, 3.73 rear
--2016 Montana 3711FL, 40'
--2014 Wildcat 327CK, 38' SOLD

Posted By: SpeakEasy on 05/28/17 10:37am

Thank God you found it!

-Speak

It's just Mrs. SpeakEasy and me now (empty-nesters). But we can choose from among 7 grandchildren to drag along with us!

2014 F-150 Super Crew Short Bed 3.5L Ecoboost
2014 Flagstaff Micro Lite 23LB

Posted By: joebedford on 05/28/17 11:30am

This photo shows the other end of this beam. On the left is one of the fresh water tanks. Above is the underside of the floor but not touching. As best I can tell, the welds on the other 3 joints appear solid albeit ugly.

I guess this beam is a spacer on the frame but I wonder if its sole purpose is to support the underbelly coroplast? It's just behind the spring hangers for the front axle.

Posted By: Lynnmor on 05/28/17 02:53pm

As the trailer goes around curves, the I-beams are flexed from side to side. Think parallelogram. That flex will cause the welds or the I-beams to break at the attachment point. You, as well as anyone concerned, need to add cross bracing to minimize the flex. Simply welding the break with no correction of the root cause will have the problem returning soon. One product is available. cross member I made my own after having frame cracks in the same area.

Posted By: joebedford on 05/30/17 07:23am

Interesting thought about the frame flex. Maybe because it's a tri-axle there are more stresses than this brace could handle. The weld didn't break - it was the steel. I'll look into this product.

In the meantime, I've sent some photos off to Lippert to ask them what they think I should do.

Posted By: myredracer on 05/30/17 09:24am

Cracks and problems are typically near spring hangers due to the high lateral forces which occur when turning. Each set of axles has a different turning radius around a turn and when making a sharp turn, like when turning a street corner or backing into a site, 2 of the 3 axles will get dragged across the ground. This forces the spring hangers to swing left/right and causes a lot of stress to the frame components and structure.

Is that maybe a floor joist? If so, the floor would be under-supported and possibly cause other problems above the floor level. Looks like a fatigue failure from repetitive high stress. Lippert frames are built the least substantial they can make them to save weight and $$ and who knows what a missing connection like that could do. Their welding can be substandard also. Is there anything else nearby that ties the two I-beams together? A piece of 2x2 tubing tying I-beams together is common and *if* there is nearby, at least the I-beams will be held together relative to each other. If the frame is indeed parallelogramming, it's not out of the question that there could be fatigue cracks in the vertical webs of the I-beams in the area around the spring hangers.

If it were me, I'd want to take down all the coroplast and inspect the entire frame. You might consider adding re-enforcement in some locations. Tying the spring hangers togther as mentioned by Lynnmor could help. It looks like that break has been there a while which could have over-stressed other areas of the frame? Not exactly the best time of the year having to deal with something like that but I would take care of it asap as mentioned above. If you were to take all the coroplast down, might be a good idea to take the trailer to a frame shop for an inspection and recommendations if needed, plus they can do the repair (and maybe in a better way than just re-attaching it like it was).

Good luck and it would be nice to see some after photos.

* This post was edited 05/30/17 09:36am by myredracer *

Posted By: Lynnmor on 05/30/17 09:55am

Here is more information direct from Lippert:
Information

Posted By: MEXICOWANDERER on 05/30/17 11:25am

This is my favorite coated 1/8" welding rod for repairing critically stressed parts. This is "magic" alloy. Light years stronger than 7018 and contains the metal vanadium. Used to be called "Super Missile Weld"

http://www.esabna.com/us/en/products/ind........fuseaction=home.product&productCode=1135

Posted By: joebedford on 05/30/17 12:35pm

Thanks for the cracked frame information. While my frame isn't cracked, it did confirm my speculation that the tabs on these cross braces should have been installed on top of the frame rails. I can see 4 of these cross brace ends and the tab is mashed underneath the frame rail.

[image]

From the Lippert repair instructions, you can see that the tabs should have been on top:

[image]

Because they're not on top, the floor of the RV is not supported by this cross brace and I believe it should be (there's about a 1/4" gap between the brace and the underside of the floor)

I think the answer to my question of what to do is to install gussets like #3 in the document above. Just HOW to do that is a bit of a problem.

Posted By: Lynnmor on 05/30/17 02:43pm

Lippert told me to weld in angle iron on the outside of the frame at each cross-member. The angles were to be installed with the tips of the iron against the vertical member and touching the top and bottom members. They said to stitch weld it. I chose to not do that as it would just hide any new cracks and it appeared to be of only marginal value. I welded the cracks and installed the hanger to hanger trusses. I made the parts to be bolted in so that repairs inside the belly cover would be possible. I now have no cracks after nearly ten times the distance that the cracks first developed.

Posted By: joebedford on 05/30/17 02:46pm

Did you bolt in triangular gussets inside the frame?

Posted By: Lynnmor on 05/30/17 03:25pm

joebedford wrote:

Did you bolt in triangular gussets inside the frame?

No, when you think about it the current cross-members have little lateral strength and attaching gussets would be of little value.

Think about it this way; if you would work the spring hangers side to side with a very large adjustable wrench, that is what your suspension is doing.

When you mentioned the tabs on the top of the frame, you should have floor joists above the frame for support. The floor should give some help to the top of the I-beams and the added trusses will keep the bottom in location.

I have photos that I can link later if you want.

Posted By: joebedford on 05/30/17 04:54pm

Yes, photos please.

For the little I've seen, there's nothing I've seen that's holding the floor other than the frame rails.

I had the same thought at you about the floor holding the top of the rails in place - for far, I've found exactly ONE screw through the floor into the rails.

Posted By: soren on 05/30/17 05:03pm

Are several of the web rods in that truss snapped in half, as they appear to be? Might be interesting to get a Go Pro video of that area while the trailer is heading down the road. I'm guessing the whole mess is about as stiff as a bowl of spaghetti.

Posted By: Lynnmor on 05/30/17 06:38pm

soren wrote:

One member on here did exactly that. Wet spaghetti is what he found.

Posted By: Lynnmor on 05/30/17 06:48pm

You can find the photos in my library. I made the yellow and red items that you will find. A brief description is with each photo.
Library

Posted By: joebedford on 05/31/17 07:14am

soren wrote:

Are several of the web rods in that truss snapped in half

I was about to say "Nah" but on close inspection of the higher resolution original photo, it appears that you're right - at least two of the rods are broken. Yoiks!

Posted By: MEXICOWANDERER on 05/31/17 10:03am

I would not drag a trailer 5 feet without boxing in the frame area of the hangers. The very best way is to rivet the box or fish plate. If welded the entire distance plus six inches fore and aft the extreme distance of hangers run inch long beads with inch no weld gaps in between.

That is why I recommended the Allstate 275. It does not heat up the parent metal as much as 6013 or 7018

I have towed trailers over washboard road so fiercely rippled that when I tried driving just a pickup truck fast enough to try and cancel the pounding it tore a riveted shock mount pad to frame loose from the truck (year 1984). I never had a frame crack. But then again I reinforced the frame first. I dragged a 31' Prowler to Tikal Guatemala then to Gracias Honduras with no problems. You can bet your bippy the terraceria (gravel road) of 90-miles length would have tested the frame.

My God, they are building "dumplings" to baby-sit from one RV park to another. How sad.

Posted By: myredracer on 05/31/17 01:44pm

joebedford wrote:

For the little I've seen, there's nothing I've seen that's holding the floor other than the frame rails.

I think you will find that there are floor "joists" that run in a fore/aft direction that are supported by the cross beams/joists. In our TT, the fore/aft joists are 2x2 thinwall aluminum tubing on 16" centers or thereabouts. Our TT also has open web crossbeams like in the OP's photo, as I encountered one when pushing a 4" furnace duct through it, blind from above. You can't possibly have the OSB or plywood floor supported only on the I-beams and crossbeams. There will also be a layer of Darco fabric on the underside of the floor. In our TT, when the factory needed a hole for the duct through the floor, they just hacked out one of the alum. joists with a sawzall - and it's in a area of higher floor loading.

There is precious little info. or photos out there on how Lippert's frames are built and what the design(s) look like.

I would guess that the web's rods in the photo (perhaps call it a "crossbeam" for clarification) underwent a lot of stress from parallelogram action of the bottoms of the I-beams flexing left/right relative to the top of them plus you'd also have the weight on the fore/aft joists bearing down on top of the crossbeam causing deflection in it. If you have something heavy above like a kitchen, it would add more stresses to the joists and crossbeams, esp. from motion when travelling.

The floor (plywood or OSB) would act as a diaphragm (in eng. parlance) and create a stiffer connection of the tops of the I-beams in a horiz. plane all around the trailer's frame while the bottom flanges of the I-beams could have more freedom to move. Perhaps the upper and lower flanges of the crossbeam had different amounts and directions of force applied to them relative to each other as a result. There is also the possibility of sub-standard welds contributing to the failure. Dunno, just thinking out loud...

Would be interesting to put a camcorder down there and see what happens as you tow it around but I would get repairs done asap. Look forward to hearing about any remedial work and seeing more photos. I would really recommend having a reputable frame shop look at it unless you are well-versed in working on these frames. We had a detailed insp. done on a previous TT for $200 and was was well worth it.

Posted By: joebedford on 05/31/17 02:37pm

myredracer wrote:

You can't possibly have the OSB or plywood floor supported only on the I-beams and crossbeams.

I have the advantage of many more photos of the underbelly. I have not seen anywhere the floor touches the cross-beams. The floor seems to be entirely supported by the frame rails and the "wing extensions" that go about 10" outside of the frame rails - nothing in the middle.

The upper 5th wheel section of the RV has the square aluminum tubes under the floor like you describe but I see no signs of anything like that in the lower level.

The floor in the 5th section is OSB. The floor in the rest is foam core plywood skin. It probably has internal studs like the walls. Maybe that's why no external support?

The kitchen center island is on top of this section of floor. The fridge and stove are in a slide.

The garage has a couple of heavy beams but there's one section of floor with no external support. At least the fuel tanks have good support. I've never noticed any floor flex with one heavy bike and heavier trike in the garage.

Posted By: myredracer on 05/31/17 02:54pm

Can you see into the floor assembly from above the floor anywhere like maybe holes for piping? You could maybe use a piece of wire to see how far down it would go before touching the fabric? Or a pipe inspection camera? In a house you're usually like 5/8" plywood supported on 16" centers or sometimes a bit more but then the plywood needs to be thicker. I know some trailers have weak floors and you can see them sag when walked on but don't know if it's because of too thin plywood or joists too far apart. Maybe someone here can elaborate as I'm interested in knowing anyway.

joebedford wrote:

myredracer wrote:

You can't possibly have the OSB or plywood floor supported only on the I-beams and crossbeams.

Posted By: joebedford on 05/31/17 04:27pm

myredracer wrote:

Can you see into the floor assembly from above the floor anywhere like maybe holes for piping?

It's 2.5"
thick:

[image]

Posted By: joebedford on 06/10/17 02:51pm

FWIW, Lippert has said that bending over the tabs on the cross-braces is correct for my rig. Still no word from them on repair procedure. They say the break is unusual but there are plenty of reports of frames folding over on the internet.

It was suggested to me that Morryde X-Braces would stiffen up the frame. I'm not convinced. Anybody have direct experience with X-Braces?

Posted By: joebedford on 07/18/17 01:09pm

OP here:

Well, to wrap this up hopefully for now and forever, I got the rig back from the repair shop. You can see from the photos that they welded the break where the cross-member attached to the frame and rebuilt all the webs in the cross-member. We'll see if it hold up.

They dropped the bottom coroplast enough to look at the other cross braces and none of them is broken.

They said two other things:

1) Morryde X-factor braces would help
2) LT tires put more stress on the frame when scrubbing sideways!!

$1100CDN for the repair. No word from Keystone, Thor, Dutchmen or whatever they are these days if they're going to help out with the cost.

[image]

Posted By: j-d on 07/18/17 06:30pm

I read all that Lippert information linked above and thought:

Rather than let it break then fix it, just build it the way it should be, the first time... It seems Lippert knows how it should be done...

If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB

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