Fifth Wheel Side Wall to Frame Attachment

[Danfiver]

I need help with a 2013 Dutchmen Denali, which I purchased new. The horizontal trim on the front corners under the raised bed location pulled loose after the first couple of trips. The dealer tightened some screws and resealed the trim. It came loose in a couple more trips. I have taken this apart and found there is a steel flange welded to the bottom of the main frame tubing that extends from the pin box cross supports rearward. Screws attaching the corner trim are screwed into this flange. In addition, screws go through this flange, upward into the edge of 1" thick plywood which is laminated into the exterior wall. These large diameter , 1-1/2 inch screws are all stripped out. Consequently, as the frame deflects up and down, the trim is pulled loose and the caulking seal is broken. My dealer does not know what else to do. My calls and messages to Dutchmen have produced no help. Does anyone have a fix for this? I would like to know what gap, if any should there be between the top of the steel flange and the bottom of the plywood sidewall and what type of fasteners should be used? If you have had this experience, please let me know if you have been able to get this fixed. Or if you have knowledge of a possible solution, I would appreciate very much hearing from you. I am concerned about excessive frame deflection and potential rotting of the sidewall due to water getting in

Thanks,
Dan

[powderman]

If I understand your post correctly, you may have more problems than trim. There should be no flexing in the overhang. Flexing in that area is an indication of weak or broken welds. If its just the screws being loose, you could put in the next size larger screws. If it were me, I would have a very good look at all the welds and cross members in the overhang area.

[Danfiver]

Originally Posted by powderman

If I understand your post correctly, you may have more problems than trim. There should be no flexing in the overhang. Flexing in that area is an indication of weak or broken welds. If its just the screws being loose, you could put in the next size larger screws. If it were me, I would have a very good look at all the welds and cross members in the overhang area.

Powderman,

Thanks for the reply. Yes, I have more of a problem than the trim, that is just the appearance issue that I thought others might be seeing. I hoped to get a dialogue going and see if anyone else had this experience and found a fix. I have had the bottom panel off and examined every weld I could see. Everything I can see looks okay. The ones I can't see are boxed in above in the bedroom area. I have been told by Lippert Components and a local trailer repair business that the frame and sidewall are attached and work together for strength and stiffness. My intention is to put in longer screws, but do not know if the sidewall is supposed to set on top of the frame flange, or have a gap that is pulled together by the screws, pre-loading the frame for stress purposes. Dutchmen service will not provide repair instructions to me or tell how the frame and sidewall should interface. I am a retired engineer and did some calculations on the frame and found that the frame deflections, without support assistance from the trailer sidewall, are believable.

[dayle1]

I had a similar problem with my '11 Cruiser, too much deflection in the steel frame. Other owners were having issues as well. Underlying problem was with the new notched front cap design that also dictated a notched frame, but Lippert made the notch bigger than necessary to accommodate multiple RV manufacturers. Older square frame design had two cross members spaced almost 2 ft apart connected to the side rails, the notched frame has them within inches of each other. I had about 1-3/4 inches of deflection between hooked and un-hooked. Pushed up the front closet floor.

The coach body does add rigidity and strength to the frame as you have been told. In my case, the angle iron attached to the side rails is just a resting place for the coach side walls. Long bolts go thru the aluminum frame of the side wall and then thru the box steel frame rail. They also stuff wood into the aluminum to keep it from crushing. This worked fine with the old square frame, but notching the frame by almost 2 ft while not adding greater rigidity in the frame and/or the wall, simply means greater deflection.

With your design, the flexing is stripping screws and in my case it was wallowing out the bolt holes thru the aluminum frame. Over time the sidewall looses it's ability to provide rigidity and eventually the frame may fail. Even if the frame doesn't fail, the front of the fiver won't remain weathertight with so much flexing. I took lots of measurements, calculations and pics. Another Cruiser owner lived near Elkhart and took his unit to the factory so Crossroads and Lippert could see the problem.

There were two major fixes involved. Lippert defined one and I defined the other. First, since the frame notch was greater than it really needed to be with our front cap design, a forward extension of the side rail was added (about 10 inches) along with a C channel addition to the cross member. This allowed another bolt to be added further forward, barely hidden by the front cap. On my frame there are really two cross members at the back of the pin box brackets, a full height crossmember that the closet floor sits on and a smaller crossmember that the bedroom floor sits on. These cross members were only welded to the side rails and I could see them separate when hooked up. Also down the center of the bedroom was a front to back floor support. I had Lippert spot weld the two cross members together and add triangular braces to the center support. I measured only 1/2 inch deflection after the repair. Multiple Cruisers received the repair (Lippert repaired mine at my dealer's facility) and Lippert changed the frame design within a few weeks for new units.

Here are some pics of my repairs.
https://www.picturetrail.com/sfx/album/view/23858981

Bottom line, the only solution is to remove the front cap and the skin under the bedroom and beef up the frame.

[Danfiver]

Originally Posted by dayle1

I had a similar problem with my '11 Cruiser, too much deflection in the steel frame. Other owners were having issues as well. Underlying problem was with the new notched front cap design that also dictated a notched frame, but Lippert made the notch bigger than necessary to accommodate multiple RV manufacturers. Older square frame design had two cross members spaced almost 2 ft apart connected to the side rails, the notched frame has them within inches of each other. I had about 1-3/4 inches of deflection between hooked and un-hooked. Pushed up the front closet floor.

The coach body does add rigidity and strength to the frame as you have been told. In my case, the angle iron attached to the side rails is just a resting place for the coach side walls. Long bolts go thru the aluminum frame of the side wall and then thru the box steel frame rail. They also stuff wood into the aluminum to keep it from crushing. This worked fine with the old square frame, but notching the frame by almost 2 ft while not adding greater rigidity in the frame and/or the wall, simply means greater deflection.

With your design, the flexing is stripping screws and in my case it was wallowing out the bolt holes thru the aluminum frame. Over time the sidewall looses it's ability to provide rigidity and eventually the frame may fail. Even if the frame doesn't fail, the front of the fiver won't remain weathertight with so much flexing. I took lots of measurements, calculations and pics. Another Cruiser owner lived near Elkhart and took his unit to the factory so Crossroads and Lippert could see the problem.

There were two major fixes involved. Lippert defined one and I defined the other. First, since the frame notch was greater than it really needed to be with our front cap design, a forward extension of the side rail was added (about 10 inches) along with a C channel addition to the cross member. This allowed another bolt to be added further forward, barely hidden by the front cap. On my frame there are really two cross members at the back of the pin box brackets, a full height crossmember that the closet floor sits on and a smaller crossmember that the bedroom floor sits on. These cross members were only welded to the side rails and I could see them separate when hooked up. Also down the center of the bedroom was a front to back floor support. I had Lippert spot weld the two cross members together and add triangular braces to the center support. I measured only 1/2 inch deflection after the repair. Multiple Cruisers received the repair (Lippert repaired mine at my dealer's facility) and Lippert changed the frame design within a few weeks for new units.

Here are some pics of my repairs.
https://www.picturetrail.com/sfx/album/view/23858981

Bottom line, the only solution is to remove the front cap and the skin under the bedroom and beef up the frame.

Larry,
Thanks for taking the time to send me such a detailed answer. I think you have some differences in construction, but some similarities. It sounds like much of your deflection was in the front pin box area. I think more of mine is just accumulated deflection, made worse by the loss of support by the side wall due to bad design and/or poor attachment. My trailer does not have the notched front end, and the frame runs tight under the front cap. Because my main supports running back to the trailer frame are actually in the boxed in at the sides and above my bedroom floor, I don't have some of the same opportunities for adding reinforcement without big changes. I am attempting to attach an image of my frame as I received from Lippert. I called Lippert after getting the run around by Dutchmen. I found Lippert to be more interested than Dutchmen and am still communicating with my contact. I am now attempting to get my Dutchmen dealer to get help from Dutchmen, since the Dutchmen service group will not tell a retail customer anything. How old was your trailer when you got help? I am a couple of years out of warranty. However, my dealer attempted to fix the problem the first year.

Thanks again

[dayle1]

Dan,

Per your diagram, you do have a notched frame, but not as significant as mine was. You also have the benefit of 4 short frame members between the front and rear cross members, I only had the 2 that carry the pin box brackets.

I did a decent job of separating deflection at the pin box vs distributed deflection of the side rails with several measurements. Here is what I did for the distributed deflection. I placed a laser level on a heavy block of wood at the back of the bedroom floor (above the landing gear). Another block of wood placed just in front of the closet (ahead of the crossmember) was the target. So they were placed about 6ft apart. Don't remember the exact number, but the deflection of the side rail over that distance was easily measured.

I don't have a good picture in my mind of how your sidewall is constructed and attached. There should be an aluminum bottom plate for the studs, is it a tube or C channel? Is the plywood laying flat or on edge? If on edge, is it continuous or inserted between the wall studs?

Regardless, if most of your problem is distributed deflection of the side rail, I think it will be difficult to improve the side wall to frame attachment for a permanent fix. My suggestion from looking at the frame design would be to have a length of steel angle welded and bolted along the inside of the existing side rails. 1/4 inch steel, 6 inches tall with maybe a 2 inch angle and full length of the side rail (5+ ft). This would also require cutting a slot in the plywood of the bedroom floor and then recarpeting the 'baseboard' edge. See what Lippert says about this approach.

Another option would be to just remove the carpet covering the side rail, weld 1/4 inch flat steel or angle to the side rail from inside the rv and then recarpet. In either case, if the side rail doesn't deflect, then new trim screws and caulk will hold.

My Cruiser was just 6 months old when it was repaired. However, if your repairs do not involve removing the front cap, then labor costs shouldn't be that much.

[Danfiver]

Originally Posted by dayle1

Dan,

Per your diagram, you do have a notched frame, but not as significant as mine was. You also have the benefit of 4 short frame members between the front and rear cross members, I only had the 2 that carry the pin box brackets.

I did a decent job of separating deflection at the pin box vs distributed deflection of the side rails with several measurements. Here is what I did for the distributed deflection. I placed a laser level on a heavy block of wood at the back of the bedroom floor (above the landing gear). Another block of wood placed just in front of the closet (ahead of the crossmember) was the target. So they were placed about 6ft apart. Don't remember the exact number, but the deflection of the side rail over that distance was easily measured.

I don't have a good picture in my mind of how your sidewall is constructed and attached. There should be an aluminum bottom plate for the studs, is it a tube or C channel? Is the plywood laying flat or on edge? If on edge, is it continuous or inserted between the wall studs?

Regardless, if most of your problem is distributed deflection of the side rail, I think it will be difficult to improve the side wall to frame attachment for a permanent fix. My suggestion from looking at the frame design would be to have a length of steel angle welded and bolted along the inside of the existing side rails. 1/4 inch steel, 6 inches tall with maybe a 2 inch angle and full length of the side rail (5+ ft). This would also require cutting a slot in the plywood of the bedroom floor and then recarpeting the 'baseboard' edge. See what Lippert says about this approach.

Another option would be to just remove the carpet covering the side rail, weld 1/4 inch flat steel or angle to the side rail from inside the rv and then recarpet. In either case, if the side rail doesn't deflect, then new trim screws and caulk will hold.

My Cruiser was just 6 months old when it was repaired. However, if your repairs do not involve removing the front cap, then labor costs shouldn't be that much.

Larry,
Thanks again for the detailed information. I can tell you have spent many hours working out the solution to your trailer. I have spent many a night waking up and worrying about mine. I will attach a document with photos that I have sent to my dealer, Dutchmen and Lippert. This will give you some idea of the construction. Sorry I did not take any photos when it was apart. But I may have that opportunity again soon. The steel flange on the bottom of the frame rail is shown in the photos. There is a view of this with the large phillips head lag screws (stripped) that go up into the 1" plywood edge. The plywood edge grain is continuous along the frame side rail. This trailer has an aluminum frame side walls, although none is visible from the bottom of this wall, just plywood edge grain. I don't know how far it goes up the sidewall, but there is a wardrobe slide on one side, so it can't provide significant structure, although thin wall aluminum framing by itself won't either either.

I have spoken with my dealer. They are contacting Dutchmen about repair options. They had another Denali on the lot that may have the same problem. We'll see where that goes. I am hoping I don't have to go the extent that you did on your rig.

[eightydid]

Have you looked on safecar.gov to see if your frame has been recalled?

[Danfiver]

Originally Posted by eightydid

Have you looked on safecar.gov to see if your frame has been recalled?

Eightdid,
Thanks for the suggestion. I looked on safercar.gov, but did not find any recalls or complaints for my issue.
Thanks again.

[Danfiver]

Originally Posted by Danfiver

Larry,
Thanks again for the detailed information. I can tell you have spent many hours working out the solution to your trailer. I have spent many a night waking up and worrying about mine. I will attach a document with photos that I have sent to my dealer, Dutchmen and Lippert. This will give you some idea of the construction. Sorry I did not take any photos when it was apart. But I may have that opportunity again soon. The steel flange on the bottom of the frame rail is shown in the photos. There is a view of this with the large phillips head lag screws (stripped) that go up into the 1" plywood edge. The plywood edge grain is continuous along the frame side rail. This trailer has an aluminum frame side walls, although none is visible from the bottom of this wall, just plywood edge grain. I don't know how far it goes up the sidewall, but there is a wardrobe slide on one side, so it can't provide significant structure, although thin wall aluminum framing by itself won't either either.

I have spoken with my dealer. They are contacting Dutchmen about repair options. They had another Denali on the lot that may have the same problem. We'll see where that goes. I am hoping I don't have to go the extent that you did on your rig.

Sorry for the late reply to the other posts. In the end, my dealer contacted Dutchmen and their reply to my stripped screw problem was "longer screws and Loctite". I removed the existing welded-on screw flange and filled the gap between the flange and the bottom of the plywood with a wood wedge. I then welded on another screw flange to the bottom the side frame tube. I used 4 inch log timber screws with a counterbore in the flange to account for the head height. I covered them with Loctite adhesive before installation. The screws went through the edge grain plywood (pre-drilled the pilot hole) and into the aluminum bottom frame element. I put in lots of screws. In the meantime I had contacted Lippert about missing welds near the pin box area. They sent a welding crew to a nearby Dutchmen dealer. The dealer removed the front cap. They crew added steel in the pin box area and back near where the side frames meet the vertical frame members. I was not there, but the dealer tech said they must have added 60 lbs of steel. Lippert covered most of the dealer's labor and their own costs. I did not measure a lot of deflection reduction when hitched. I bought a Lippert AirRide pinbox and installed that myself. I now see a 40-50% reduction in deflection during travel over rough roads (and better ride). Hopefully my troubles are over and I will not have future problems. Lippert treated me very well, unlike Dutchmen. Dutchmen's solution would not have eliminated the gap at the bottom of the sidewall, so the trim movement problem would not have been solved. After about 2000 miles of towing, the trim has not moved.

[dayle1]

Sounds good that you haven't had any more issues with the trim. And it is great that Lippert stepped up to the platel But since they reinforced the rear of the gooseneck frame, it sounds like they have experienced this problem with other Denali frames in the past.

[MnTom]

Dan, I just repaired the same problem on my 2006 Dutchmen. There were no screws on mine that went from the flange to the sides. Mine did not have a flange, but there were four tabs welder to the frame that the sides sat on.

There were six long tech screws that held the front on mine and five out of six were loose.

What I did was to pull the aluminum back on the bottom (be careful because it kinks real easily) and put four of the tech screws in new holes and drilled holes for four carriage bolts through the wood and the metal frame (the same way the tech screws went) and bolted everything together.

[jesilvas]

Just curious for statistics sake, are you using the 5th wheel hitch or a GN adapater of any sort other than factory?

[Danfiver]

Originally Posted by MnTom

Dan, I just repaired the same problem on my 2006 Dutchmen. There were no screws on mine that went from the flange to the sides. Mine did not have a flange, but there were four tabs welder to the frame that the sides sat on.

There were six long tech screws that held the front on mine and five out of six were loose.

What I did was to pull the aluminum back on the bottom (be careful because it kinks real easily) and put four of the tech screws in new holes and drilled holes for four carriage bolts through the wood and the metal frame (the same way the tech screws went) and bolted everything together.

It appears the construction on your Denali is quite different than my 2013 model, but the end result was similar. In talking to the Lippert rep, I had the feeling he was interested in my case for various reasons and he was interested in what Dutchmen would do for me. There probably is a history of problems on that model. According to what I understood, Dutchmen specifies the frame and attachment method to the camper body. I also found out the hard way that Dutchmen service personnel on the Help line will not give out any useful information on repairs. I has to come through a dealer service inquiry. And if your dealer has a dysfunctional service liaison, it becomes very difficult to get good information.