f350 frame, what to do?

[MUDKICKR]

i have a frame im wanting to redo for a f350 project i have. its a 1990 f350 crew cab long bed frame, and its a factory dually, so its 2wd. i have already installed frt leaf spring brackets on it for the 4x4 swap, but im thinking about boxing in the complete frame while i have it tore down. im wanting to use it under a daily driver/tow rig. trk will be used for long distance driving and daily driver use. 4wd will only be used when needed. basically what the trk will be used for is to and from work daily (when not riding the motorcycle) and when needed tow a trailer out of state and in state, and as a family vehicle. i plan to keep the truck as long as i can, and to understand what i mean by that i have owned my current trk since 1998, and still drive it but i really need more room.
main concern is ride quality, would it help or would it hurt it? also concerned in the cab, if i use poly bushings would it crack the cab cause the frame doesnt flew enough? or would it last longer due to not flexing as much?

 

[junk]

My crewcab would flex a lot when running through an off camber area. The bed would flex compared to the cab in ways that don't seem right. I would be afraid the fully boxed frame would not flex and crack over time. I wouldn't go through the extra work. I would just leave it as is.

 

[MUDKICKR]

any body else have any real world experience?

 

[freebird01]

id have to agree with junk.... ive seen my extended cab do the same thing when pulling in and out of fields through drainage ditches....the frames are made to flex.

i plan on doing poly bushings on my ext cab... but the frame will be staying as is.

 

[sassyrel]

dont box that frame in!!! thats for street only vehicles......as they said,,it has to flex.....

 

[GOOSE]

I see no reason to box it. These things take a beating and come back for more. I've had 3400lbs in the bed and have had it grossed at 28,000lbs pulling a back hoe on a 9 ton trailer. A good sand blasting and epoxy paint should be all that frame really needs.

 

[MUDKICKR]

i understand that a frame does need to flex, and even boxed in it will still flex, but not as much as factory, but the suspension also is designed to flex, so why would making it not flex be the worst thing to do?
but after doing some other research i believe i wont be boxing it in completely, but i will be boxing in the frame at some places along the frame, and i will be building me another type of transmission crossmember, which will be boxed at that point.

 

[justinray]

i understand that a frame does need to flex, and even boxed in it will still flex, but not as much as factory, but the suspension also is designed to flex, so why would making it not flex be the worst thing to do?
but after doing some other research i believe i wont be boxing it in completely, but i will be boxing in the frame at some places along the frame, and i will be building me another type of transmission crossmember, which will be boxed at that point.

Have you ever seen a leaf or ball joint or tie rod that 'overflexed'? No imagine that on a frame. Best case scenario is you just snap your welds. But it WILL put extra stress on most suspension.

 

[oldmisterbill]

I pulled loads of tractors 2-3 at a time in and out of old farms - fields (couldn't be fussy) never a frame or actually a spring problem. I've seen the frame flex like crazy -kept all wheels on the road . Suspension neede the give to allow the flex also. I think if a stronger frame is necessary you need a superduty. The F350 crew is a tough truck. Experience tells me so.

 

[Dieselcrawler]

Cracked a frame in 2 spots from my wheeling I do. Now that I added a cage, my frame is stiffer than before. Time will tell on this one

 

[MIDNIGHT RIDER]

Regardless of the stiffness/flex factor, a boxed frame will rot out in short order.

Many smaller trucks and SUVs have boxed frames and, after a couple years, you can poke a screw-driver through them just about anywhere you try.

Being in the tire-shop business, I am under all makes/models of vehicles every day and, regardless of make, I see rotted-out boxed frames several a day.

The mud and crap gets in and just can't get out; I think manufacturers know this and purposefully box them to shorten the life.

 

[chvycmnslvr68]

i understand that a frame does need to flex, and even boxed in it will still flex, but not as much as factory, but the suspension also is designed to flex, so why would making it not flex be the worst thing to do?
but after doing some other research i believe i wont be boxing it in completely, but i will be boxing in the frame at some places along the frame, and i will be building me another type of transmission crossmember, which will be boxed at that point.

I can tell you from personal experience that if you go welding to the fram and making it stiffer in places than others that it will break somewhat clost to wherever you make it stiffer .... P?U frames are designed to flex and that fles has to carry out for the length of the stressed area and be gradually released .. if you stiffen any given area it will not be able to carry the flex through that point and will cause the areas close to the stiffened area to do more flexing .. therefore resulting in a broken frame ... I would leave it alone ... FORD spent miollions designing the frame and testing it and unless you have a very high degree in mechanical engineering you wont be able to out smart the team that designed these frames ...