DREAD THE THOUGHT OF DRILLING OUT THE BED OF MY 05 KING RANCH. I HAVE A REESE 5TH WHEEL HITCH THAT THE MOUNTING RAIL HOLES LINE UP PERFECTLY WITH THE 4 CENTER BED BOLTS. DOES ANYONE KNOW OR HAVE EXPERIENCE IF THESE 4 BED BOLTS ARE STRONG ENOUGH TO SAFELY HOLD THE HITCH WHILE TOWING MY 12,OOO LB TRAILER. THE BOLTS HAVE A NUMBER 10 ON THE HEAD WHICH I WILL ASSUME IS A GRADE 10 .

I'AM NEW TO THE SITE AND REALLY LOOK FORWARD TO HEARING FROM ALL THE EXPERIENCE ENTHUSIAST HERE

 

In Short, NO!!!. I would wager the 10 is the metric size, not grade. Not sure, but I believe my 5th has a lot more bolts, and larger. 10mm is between 3/8 and 7-16". I believe my hitch rails are mounted with 5/8" bolts.

 

But would the hitch be located properly when using those holes? The pin should be just ahead of the axle, 2-4 inches according to Reese.

Also, the bed may have a channel that raises the bed off the frame that may not be strong enough to take the load of the 5th wheel. You really need thick (1/4" +) steel brackets between the frame and bed to which you attach the hitch.

 

local Reese dealer (been doing it for 20 years) removed the four center bed bolts and replaced with grade 8 1/2 inch bolts to mount the hitch,, had the hitch in my 2003 and moved over to the 05 KR,,

he indicated he has been doing this for several years if the holes line up,, he also makes sure that spacers are used so there is no chance of compression,, ford has some spacers installed from the factory,,

just did a 6,000 mile trip with the fiver in tow and nothing moved and the nuts are still at the correct torque value,,

what a clean set up,, now the next owner of this 05 will have a clean bed to use and enjoy,, still have Ford's OEM hardware to re-install when I move to the next truck,,

 

Thanks For The Reply, The Hitch Is In The Proper Position In Frt Of The Axle And The Rails Bolt Perfectly, In Fact I Swaped The Rear Bed Bolt Out For The Center One As They Are An Inch And A Half Longer So They Worked Great But I'll Take Your Advise About The Bolt Grade. You Know When Ford Does That Commercial To Hold A Truck Up In The Air By The Bed Bolts Make Me Think There Ok To Use, If Anyone Knows What Grade The Factory Bed Bolts Are It Would Be Helpful. This Is My 5th Superduty Since 2002 And My Dealer Always Flips Out About The Holes In The Bed So I Like The Idea Of Using The Factory Bed Holes And As Will Save The Original Hardware, Thanks Again

 

I find it a bit odd that I just bought an F350 yesterday, and am in the process of pulling the fifth wheel hitch off my F250 tonight. And I was also wondering about the strength of the assembly, using those four bolts. And I am also pulling 12k pounds. (By the way, I love my new mini-semi. I have spent the last three years cursing people who drive these monster dually 4x4's, and now I own one. Talk about instant karma...)

I'm a mechanical engineer. So you can safely assume that any advice I give will be inaccurate and incorrect. I have not pulled the bed bolts off the F350 yet. But they appear to be of a smaller diameter than the F250 1/2" bolts.

The bottom line is this, I believe- the only forces that could be problematic for those four bolts are either braking or something else we don't want to think about. Like accelerating. Ie. a rear ender. And that last one is not really part of the equation. Having said that, I know that it's possible to set the trailer brake controller so that grabbing occurs. That would be a bit more forceful than simply skidding the trailer. It's under that condition that I would expect the worst scenario.

I notice that some fifth wheel assemblies use eight of the bed bolts. However, the fifth wheel itself uses only four. So four bolts hold that hitch down.

One simple answer to your question is to call hitch manufacturers. Or to simply look at pictures of hitches and how they attach. My feeling is that even four bolts of the diameter on the F350 will be able to handle the shear forces involved. I could run the numbers on bolt shear strengths, but I already know that those four bolts far exceed any possible forces the trailer dynamics could exert on them. But then there is the factor of safety. I'd say a factor of two would be sufficient. That's a blind guess. And I'd say that even with that, those four bolts are suffiient. But that would be for new bolts.

Ok, I just pulled one of the bolts. They look to be 1/2 inch diameter, or close to it.

Four of those bolts will easily take a 12k pound trailer. And if it helps at all, I have been pulling a 12k pound trailer with my F250, with these same diameter bolts, for years. And I've had it on all conditions including off road.

By the way, that's why I got the F350. Try pulling 12k pounds up the grades in Humboldt and Mendocino county of Northern California. Oh my god, I parked my F250 for the last time tonight. And I'm totally excited about putting my machines behind my new 2003 F350 mini-semi. Yeeah. Rock n roll!

 

boring oldman, thanks for the reply, i feel confident that these bolts will be more than adaquate to hold the hitch, i called reese and all they say is follow there instructions, ive looked at the hitch that uses all 8 holes butthats to much iron in the bed. the ford bolts if youlook closely are a different diameter near the head from a rt side to a lt side bolt. i think it may have something to do with alignment during installation. as for compression of the bed? if youlook into the bed x member there are steel sleeves in the bolt hole path so bed sheetmetal wont collapse or have any movement.this sure beats drilling 16 holes in the frame and box to install the hitch. not knowing the bed bolt grade or how to determine them on a metric bolt i bought some grade 8' s and will probably use them till i find the metric grade. i think if you periodically check the torque to see if bolts are stretching or moving after a towing trip would be a wise thing to do

 

I removed the stock bed bolts, removed the threaded clips from frame, run a 5/8 drill bit through the frame (minimal metal removal), then used the 5/8 carriage head bolts that come with the hitch. The carriage head bolts are no better than grade 5, so the bed bolts are probably adequate in strength but the carriage heads give a smoother finish. It is a little close for tightening, but not too bad.

 

Can anybody explain to me why the genius at Ford put the two bolts behind the axle (bed bolts) at just the right position for a 5th wheel rail, but put the ones in front of the axle 1&1/4 inches farther apart? Fore and aft dimensions are correct for the Reese hitch, but the front bolts are too far apart!

Previous forum entries tell of people who were able to use all four bolts - are there two different bolt patterns?

 

"Previous forum entries tell of people who were able to use all four bolts - are there two different bolt patterns"

Ummm, maybe just the Maryland bound trucks??? Mine was the same way...rear holes matched, front holes were off...so I said the heck with factory and drilled 8 new holes and mounted the rails with stainless steels cap bolts and nuts - exactly where the rail is supposed to mount and left the bed bolts alone. That hitch ain't goin' nowhere!

 

BP,
Are these stainless bolts that you are using 316? 304?

I know that these alloys of stainless are excellent for corrosion (especially 316, moreso), but was always told (and experienced) that they are not as strong as their carbon based counterparts. (Not to mention galling...PST works great!)

I am curious as to what grade SS you are using.

 

Sorry, I can't tell you without checking with my son. He got 'em for me from where he works. He's big into welding and metal working, so I trust his judgement, I just don't know what stainless he used. I do know whatever it was hasn't budged in almost a year now. I'm pulling a Prowler fiver, 30 foot. And I love this 6.0. I have to keep checking the rear view to see if I still have the trailer behind me!!

 

Am I missing something here?

Or are all you guys talking about putting in a 5er hitch rails without putting in the brackets that go to the frame from the underside of the truck box under the hich rails?

 

Some hitches have rails running across the bed, i.e. at right angles to the
truck body frame rails, while some others run parallel to the frame rails.
Ones that run across typically use just 4 bolts attached via brackets to the
truck body frame, but ones that run parallel can of course utilize more
positions for attaching to the truck frame.

I use a DSP hitch (parallel rails), and I use three 1/2" Grade 5 bolts thru
the bed on each side attached to 3/8" thick brackets on the truck body
frame. This allows a broad bolt placement pattern, with two near the center
line of the rear axle, two forward of it and also two behind it (for the hitch
in total), which makes it very solid on hard acceleration, braking and side
stresses.

Typical automotive 1/2" Grade 5's have a yield strength of 92000 psi, and
Grade 8's have a yield strength of 130000 psi. Most (if not all) recreational
5th wheel trailers have GVWR's well below the ratings on just 1 of these
bolts (although I wouldn't advise pulling with just 1 bolt :-).

FYI, here's some useful info on bolt grades and strengths:

<a href="http://www.sizes.com/tools/bolts_SAEtork.htm">SAE Standards for Bolts</a>
and
<a href="http://www.americanfastener.com/technical/grade_markings_steel.asp">American Fastener - ASTM, SAE, and ISO Grade Markings</a>

 

I would dread drilling my king ranch too! They are too pretty to hack on.

And yes,yes grade 5 bolts. If you like gold bolts then have your grade 5's powdercoated or dipped. Grade 8's are over kill and can cause some real problems.

Remember grade fives have 3 hash marks on the head. 3.

Peace