2016 21BHS Frame Cracks

[tt2retire]

I thought I had lucked out and not had much of a frame crack problem in my 21BHS (manufacturing data 12/2015) but after spending most of yesterday mapping out where work is needed, boy was I wrong. At least my axel mounts are still looking good so far.

I've attached a hand sketch of where I see at least the beginning of cracks in the welds. The sketch has small yellow highlighted labels of 01 through 25 of the areas that I could access without removing tanks etc. I'll have to break out my endoscope to search those other spaces.

I've also attached a few pics of the worst ones I've found so far (#04, #06, #08).

If anyone would like to post pictures of what a fixed weld looks like (i.e. with a gusset or just a re-weld?) that would be much appreciated.

Ed...

[Powder Hounds]

Hi Ed,

Yup, pretty consistent with other rigs over the years. LL did not add enough structure to reinforce the frames, and this is the result.

But, it can be fixed, permanently. We had our 2015 RBS repaired roughly six years ago with absolutely no issues to date. We had about twenty gussets added to those problem areas, we doubled up gussets specific to the slide area, in front and behind the axles, a couple of inches apart.

The old archive has a lot of information about this issue. I would contact a reputable aluminum fabricator/ welder and get some gussets cut out and welded in.

Cost to us was about $3000 CAD and took about a week to complete.

Good luck!

[Merlin]

That's a lot of cracks! Everyone who has had repairs done so far have used gussets, not just re-welding. I just fully inspected my 10/14 build date 16TBS and found only one 1/4" crack in one weld. I'll keep track of the welds before every major trip.

I used to be a huge fan of LL campers because of the no rust/no rot construction. Now that so many have had failed welds, I'm no longer recommending them as a used camper without a complete professional inspection of the frame. I'm also encouraging anyone with failed welds in the U.S. to fill a report with the National Highway Traffic Safety Administration. There has been one recall for a few campers for failed welds as a result of NHTSA investigations.

[tt2retire]

I will definitely file a report with the NHTSA, so thanks for the reminder.

I would really like to see examples of how the gussets were installed so I can better determine what a good aluminum Welder will propose vs a bad aluminum Welder. I'm also wondering if they re-welded the cracks and then installed the gussets? Attached is a quick sketch of what I'm imagining the installed new gussets would look like.

The last welder I used for strengthening the bumper has retired, and even one of his new welds has cracked at the inside back right corner which surprised me (pic attached).

Thanks,
Ed...

[tt2retire]

Also, what was the thickness of the material of the new aluminum gussets?

[Merlin]

Here's a long thread on the frame failure recall. If you read through this, it shows photos of the repair using 3/8" plate gussets/boxes welded to the 3/16" frame material. This is what KZ RV did for the recall work.

You need a good aluminum welder, but also someone who can engineer a gusset for the stresses at each joint. I'm not an engineer, but I'll take a WAG that just re-welding the joint or putting a gusset in places they won't help isn't going to fix the frame permanently. Again, I'm not an engineer, but I like the idea of boxing in the bad joints and not just using a single gusset.

https://aluminumcamperforum.com/index.php?topic=1036.0

[tt2retire]

Found a nice picture from Powder Hounds in another thread showing two gussets installed on one of his fixes.

https://aluminumcamperforum.com/index.php?topic=1195.0

Thanks all for your help, think I'm now ready to start interviewing potential aluminum welders.

Ed...

[Paul]

I wonder if I should remove the enclosed underbelly to check. When I got the recall done there was one crack

[tt2retire]

I would if it were my trailer.

My assumption is that the more cracks there are, the more the frame will wiggle around and twist. Having more wiggle probably leads to more stress and causes more cracking. We are not going to use our trailer until after we get the current set of cracks fixed/reinforced.

One thing that I'm noticing in my frame cracks is that so far the majority are vertical cracks. I would expect that the welding of the frame components to the bottom of the aluminum floor would increase the shear strength like adding plywood does to a wood frame. I am noticing some very small cracks in a few of the welds from the frame to the underside of the aluminum flooring. Maybe the shear strength from the flooring isn't as good as expected since I don't think that the individual lengths of flooring are welded to each other??

Ed...

[djsamuel]

My 2013 21BHS (purchased new) was built in November 2012; before the Thor buyout.  I just went under and checked my frame and there are no cracks anywhere and the welds all look good with a lot of gussets.  I've towed that trailer from Florida, out to Arizona and Utah, up to Massachusetts and several trip to Tennessee and Virginia.  From my log, I have over 16,000 miles on it.  I wonder how much Thor changed the design, the aluminum used, or the welding specs.  I also wonder if there was a talent drain after the facility was moved and the Livin Lite facility was shut down.  If people not used to welding aluminum were used, that may have had an effect as well.  It is a shame becuase there was so much potential with these campers.  Ours has been so good we don't foresee ever getting rid of it.  It has the aluminum roof and the aluminum floor.

[Merlin]

Interesting idea about the change in manufacturing location and weld quality/gusseting. As I've mentioned in other posts, I visited the small original factory in Wakarusa, Indiana when my camper was being built in 2014. I don't remember thinking there was anything wimpy about the frames coming out of the welding shop. Perhaps there was a change when they were bought out and moved production to Middlebury, Indiana at the huge (gigantic) KZ plant the next year.

[djsamuel]

And I belive there was an interim stop at the Crossroads Factory before they hit KZ.  There was a lot of turmoil before they were shut down.

[tt2retire]

@Powder Hounds

Did you have all cracks repaired before having the gussets installed?

I'm trying to figure out how much to remove before having the welding fixes made. Some of the cracks are close to existing wiring/pipes/hoses/tanks, so I'd have to remove a lot before the welding. If I only added gussets, and didn't repair the cracks I could possibly get away with removing less.

It's likely I'll have the fresh water and grey water tanks removed before welding starts, but I'm not sure where to stop removing things.

Thanks

[Merlin]

I'm not sure if powder hounds will be on to respond. I can say that all the photos they posted showed repaired cracks as well as the added gussets. Welders can shield things close by if they have access to the joint.

[Powder Hounds]

Hi,

Yes, they did repair all the existing cracks, but the focus was adding in the gussets. With all the welding, I had maybe two wires that had some burnt material but, nothing major. They didn't have to drop any of the holding tanks or move any plumbing lines as well. More emphasis was on the slide side.

When I initially discovered the frame issues (on an extensive trip) I had a welder redo some of the problem areas just so we could get back home. Those areas all eventually cracked again. It wasn't until the gussets had been installed did the problem go away. No issues with the main north south frame, or the A frame, everything was around the perimeter cross members.

On a side note, have your fabricator reinforce your rear bumper at the same the frame is being worked on, so in the future you could mount a bike carrier or a tray to carry additional items. Something I wish I did.