Fifth Wheel Hitch

[beartrace]

Heads up on a problem I found.



I have a Rhino lining in the truck bedwith a 5th wheel hitch mounted. I removed the hitch and rails that it sits on from the truck bed. There was rust starting to form around the bolt holes in the truck bed. The vibration or weight from towing the 5th wheel had caused the Rhino lining to be rubbed off around the bolt holes. I am happy I caught it right away and fixed the problem.

 

[Turbo Thom]

Yup:

That's why I was advised to install the rails first. You don't want nuttin between the rails and the bed.



. . Preston. .

 

[beartrace]

Preston,



I was advised just the opposite and it seems it was the wrong advice. When I asked the installer if I should wait until the 5th wheel hitch went in he said no. I think that he was afraid that I might not come back and wanted the sale now. Anyone else out there that had it installed as I did should check for the problem.

 

[klenger]

beartrace



I'm confused. Is you hitch mounted on top of the lining?



I think mounting the hitch rails directly on the bed is just asking for rust, as it creates a low spot for the water to collect, and the bed is upprotected. Of course, in Colorado, things don't rust here anyway because of the dry climate.



As far as compressing the lining, I have a Line-X, and I really don't think it compress all that much after you initiall torque the bolts. Just MHO.

 

[beartrace]

Yes, the hitch is on top of the lining. Movement or friction caused the lining to wear thin around the rail bolt holes on the truck bed causing exposure of unprotected metal. Rain water got in there and caused it to start to rust. The rust was very minor but left unattended it would get worse with time. I guess if the lining was put on after the hitch was installed the area would be sealed from moisture.

 

[CPH]

hitch

What type of hitch are you running? Do the rails run across the bed or front to back? I have an old RBW that the rails run front to back. It came with shims that fit in the bed groves to make a perfectly flat surface to mount the rails to. I have had mine in since 97 and have had no movement of the rails to cause my rhino lining to wear. I would check all of your bolts and make sure your rails are TIGHT to the bed. You should also have some kind of mount support under the bed that ties directly to the frame. There should be some type of shim or washer to fit in the bed groove under the bed to make the surface flat so the bolt is not moving in the groove. Someone with a new Reese hitch can tell me if I am mistaken. In any event you should check all your mounting bolts.



cph

 

[beartrace]

I have a Reese 15K 5th wheel hitch. The rails are mounted across the bed (from side to side). I'm not sure what you mean about a support under the bed. Mine just have washers on the underside and then the nuts.

 

[SnoKing]

I do not think LineX would have that problem, it sets up harder. SNOKING

 

[JSoloman]

I have the Line-X lining and my hitch rails were mounted after the lining was applied. No problems with wearing through on mine.

 

[Turbo Thom]

Beartrace:

On the subject of on or under the lining, The 98 12V I got the wife has a OEM plastic lining in it. On top of that, the rails are mounting on the lining. Is that wrong? The lady we bought it from towed a fifth wheel from Fla to Co and back 4 or 5 times. Said she had no trouble. Would I do mine that way? I don't thing so!



Point. The only time you would want to have anything between 2 metal objects is as a dampner for vibration and sound proofing. The hitch is not either case. Metal to metal and I will take my chances with the rust.



. . Preston. .

 

[dmurdock]

Originally posted by beartrace

I have a Reese 15K 5th wheel hitch. The rails are mounted across the bed (from side to side). I'm not sure what you mean about a support under the bed. Mine just have washers on the underside and then the nuts.

Hold on, are you saying that the only thing holding your rails to the bed are the bolts which go thru the rails??? These bolts should also be going through added supports (which are part of the hitch kit) which run under the bed (parallel to the ones inside/on top of the bed) and bolt to the frame. If not, I'd get this fixed ASAP... I would NOT trust the metal of the bed to hold up to towing very long if it is the only thing your hitch is attached to...

 

[klenger]

What dmurdock said.

 

[CPH]

Hitch

Bingo! Dmurdock may have said it better than me. The hitch rails should have more than washers under the bed. You do not want the thin metal of the bed and some washers taking the load.



cph

 

[beartrace]

Thanks for all the feedback. It appears that you have discovered another potential problem with the support under the bed. The way it was mounted was washers only. I am looking into the additional support that you suggested and will add before towing the 5th wheel again.

 

[beartrace]

It had been awhile since I took out the 5th wheel hitch and went back and checked the mounting again. There is a heavy piece of rt angle iron attached to the frame and then to one of the bolts on the underside of the rail. The other rail bolt is held only by washers to the bed. It looks like this is good. Anybody have any comments?

 

[Goddard]

this should be correct. two bolts should be holding the bracket to the frame and one bolt for the rails to the bracket. the other bolt for the rails will just go through the bed... ... ... ..... as for the plastic liner in between the hitch rails and the bed!!!!!!!!!!that is a bad thing waiting to happen!!!!!1 i can see no way to keep the right torque on these bolts with the plastic liner inbetween there. my semi-professional opinion.

 

[dmurdock]

I would just periodically check the torque of these nuts. If the liner is already "squished" as much as possible, the only thing you really have to worry about is the bolts "sliding" back and forth and grinding the liner down, thus reducing it's thickness and the effective torque on the bolts. Just keep an eye on it... you should be O. K.

 

[TowPro]

I am sure glad you guys spoke out about the mount only using washers under the bed!



I have the Reese 20K, it uses 4 "L" brackets on each side, each rail has one front and one back L" bracket per side.



I have the factory bed liner so instead of cutting long groves for the rails to sit in (and making it hard to get the pins in and out) I used a hole saw and I drilled 1" holes (might have been 1. 5") for each mounting location, then used grade 8 washers to fill the space between the bed and the rail as the rail sits on top of the bed liner. Just in case the rail starts to flex in the middle, I added 2 center bolts to each rail, also spaced with washers, but only have large washers under the bed where the nut is. (nothing else there to mount to)



I have towed my 11K 5th wheel about 6K miles with it and nothing has come loose.



Down fall is crud can get past the bed liner into the holes, plus your bed liner is now perment unless you remove the hitch rails.



plus its hell trying to shovel something out of the bed.

 

[Dkevdog]

I had a Rhino lining and it is way too soft for me. Your problem is why I went with Line-X.



Kev