I'm considering paying a RV industry welder to add gussets /reinforce the welds in the under deck / pin box area. A warranty repair for a crack under the bedroom slide was just completed. As part of repair, the under deck flex was measured @ 1/2" on both sides which is, according to Forest River, within spec. I'm leaning towards leaving it but while its at the dealer and apart, I'm considering having it reinforced to possibly to mitigate future issues.According to Forest River (below) it won't violate my warranty which has expired anyway. Its a 2018, 13 month old 5th wheel.FR ADVISED THAT THE FLEX AMOUNTS ARE NORMAL, THE CX MAY ADD GUSSETS FOR SUPPORT AT THEIR OWN EXPENSE BUT ANY AFTERMARKET REPAIRS ARE NOT COVERED UNDER WARRANTY. ADDING GUSSETS DOES NOT VOID WARRANTY AS LONG AS THE ORIGINAL FRAMING IS UNAFFECTED/CUT. ACI'm supposed to review the scope of work and cost with the welder next week. I value the opinions here in RV,net; would you do it?Thank you,Larry & Sylvia

A bit of flex is normal, if the frame is too stiff the stresses can cause cracks.

Add as indicated while its open. If you plan to keep it for a while.

At the least, look over the factory welds and make sure they are up to proper standardsB.O.

My thought would be where and how are they measuring the flex? If you measure it at the right place, a huge amount of flex will be within spec.

B.O. Plenty wrote:At the least, look over the factory welds and make sure they are up to proper standardsB.O.The dealer looked over the welds when the under deck cover was off, they said they were OK. The side wall welds were horrible where the crack under the bedroom slide occurred. All of them were small tack welds and one of them broke. The broken weld wasn't where the crack under the bedroom slide occured, so I requested Forest River to remove the under deck cover and inspect welds in the frame. It took 6 week for them to approve it and perform the work.

Would you pay a welder to reinforce your 5th? | Good Sam Community

TxGearhead
Explorer II
May 04, 2019
Good call.
Leeski_Clan
Explorer
May 04, 2019
Thanks for your thoughts / replies. I wanted to let you know that we decided NOT to have the under deck framing reinforced.

The crack under the bedroom slide, that my 5th was originally in the dealership for, was fixed under warranty, The fix comes with another 1 year warranty. If it cracks again, I foresee the warranty being denied because I had the frame reinforced.

I have a 5th Airborne air pin box that may help avoid future structural issues caused by hitting bumps in the road. So reinforcing the frame may not be needed as much.

Happy camping,
Larry & Sylvia
twodownzero
Explorer
May 01, 2019
I would if I thought it was necessary without a second thought. Steel is not hard to work with; just about anyone can install some gussets that'll give you peace of mind for a long time.
mapguy
Explorer
May 01, 2019
Leeski Clan wrote:
romore wrote:
A bit of flex is normal, if the frame is too stiff the stresses can cause cracks.

Great point and Yes, I was thinking about that too. Reinforcing the structure may make it too brittle and that could cause other issues. RV frames need some flex so it can bend under stress and not break.

It depends on whether you want caulk to stay intact on the nose of your trailer after repairs. 1/2" flex is marginal as to being within the stretch specifications of most typically used RV caulks.

A bit of flex is normal, if the frame is too stiff the stresses can cause cracks.

I don't agree fully with this statement in your context. Frame should not be a damping device.
myredracer
Explorer II
Apr 30, 2019
Beware if they come back and say "it's within spec.". We found a problem with our frame the day after we owned and that's what the dealer said Lippert told them. Long story short, we then went to a gov't (BC) designated frame & axle inspection facility who did a detailed inspection and report. They said the frame was the worst they had ever seen! I was shocked at all the things they found wrong with it. We ended up getting the TT replaced with a new one with a waaay better frame with zero arguments.

I would stay far away from a dealer when it comes to frames. Go to a frame & axle shop that is also a designated inspection facility (if you have those) and has experience with RVs. Don't go to any old frame & axle shop either. Our dealer sent our TT down the street from them to get shocks installed. Wasn't long before one of the shock brackets fell off the frame due to bad welding (no penetration). Took it to the above shop and they were able to peel the other 3 brackets off with a crowbar.

I don't trust Lippert frames as far as I can spit. If we ever get another TT, it will NOT have a Lippert frame.
N-Trouble
Explorer
Apr 30, 2019
I had to. Following spring over axle flip the frame developed a long horizontal crack between the wheels. Lippert covered the cost of repairing the cracks and adding three crossmembers. Really beefed things up underneath.
TxGearhead
Explorer II
Apr 30, 2019
^^^Yep X2. I was in the refinery/petrochemical turbo machinery world for 40 years for Shell. No way I would let a welder decide where and how to weld on a piece of critical equipment. Be a lot of talking, meetings, and phone calls first.
Charles2222
Explorer
Apr 29, 2019
Looking at a weld and calling it bad?We called lots of welds big ugly and strong.X Ray or sonic or dye is a way to test welds.How would I know?Was a steam fitter for lots of years.We even had stress releaving on lots of our work.Hard to believe the people that build these frames just hap hazard put them together.
Allworth
Explorer II
Apr 29, 2019
fj12,

There is a huge amount of design goes into the frames. Then the manufacturer sets the cost limit of how much of it they are willing to pay for. The "acceptable" failure rate is not set by the engineers and the ultimate design is reduced as long as basic life-safety standards are maintained.

Money talks!

(What weight WF beam are you running for that 40' span?)
TxGearhead
Explorer II
Apr 29, 2019
Being a good welder is quite different than being a structural engineer. What you and I think makes sense may be 180 degrees wrong. Many welders can do a lot of structural repairs based on a lot of experience, but it's just an uneducated guess. I've known a lot of professional welders and none of them have any structural design training. Asking a welder what the bending force to failure of a 12" I-beam over 40' would be about like asking me. I dunno.
You know the difference between cowboy boots and welder boots?
Cowboy boots the BS is on the outside.