Fifth wheel questions

Funny, I've owned a LOT of trucks and none of them had that sticker. Now the one new truck I bought did have stickers that said never weld or drill frame flange. But hey whatever floats your boat. I certainly don't think a guy needs to be certified to hold a still any more than a guy needs to be certified to hold a shovel. It's not like that ase certification joke of a class teaches a guy how to be a structural engineer.

 

I think they say do not drill or weld to the "flanges"?
(Shrugs)

 

Here we go... From https://www.fmcsa.dot.gov/regulations/title49/section/393.201

§ 393.201: Frames.


(a) The frame or chassis of each commercial motor vehicle shall not be cracked, loose, sagging or broken.

(b) Bolts or brackets securing the cab or the body of the vehicle to the frame must not be loose, broken, or missing.

(c) The frame rail flanges between the axles shall not be bent, cut or notched, except as specified by the manufacturer.

(d) Parts and accessories shall not be welded to the frame or chassis of a commercial motor vehicle except in accordance with the vehicle manufacturer's recommendations. Any welded repair of the frame must also be in accordance with the vehicle manufacturer's recommendations.

(e) No holes shall be drilled in the top or bottom rail flanges, except as specified by the manufacturer.


So yes, as long as you don't weld, or drill holes in top or bottom of frame you should be good.

-Steven

 

Surprised nobody mentioned that the OP should use high tension bolts.

 

There's a certification for that???

Huh, who knew!

Oh, Well.... Next.


General Rules.
No Welding on Frame Rails.
No cutting or drilling of Flanges.
Grade 8 or better hardware.
No oversized holes!!


As always there are some exceptions, Like the hinge and hitch plate on a dump truck!

 

apparently you must not know what a welding helmet is for.

i have done a ton of welding and yes i have flash burned my eyes and it is very miserable. but it was from throwing tack welds without a helmet. never had that problem welding with a helmet on. only took once to learn my lesson and never flash burn my eyes again.

 

I would never add to an existing slider. I would at least get a longer one from a salvage yard.

 

Why not? If it's bolted down properly there's no harm.

 

Guess you don't realize all the longer ones from the factory are is a standard length, with an extra section bolted behind it.

Absolutely nothing wrong with adding extenders in, that's EXACTLY how the truck manufacturers do it at the assembly plants.

 

Welding on a frame or flange reduces it's strength. They are heat treated. Drilling near the flange also reduces strength. The flange usually consists of the 90 degree radius, the upper and lower lips. with the width of the lip extended into the rail . Look at it like angle iron. 2 pieces, upper and lower angle iron. Anything in between is drill-able rail. The bolts will usually be 1/2 inch coarse grade 8 ( 6 ) lines or marks in the head.