Project "Autonomous" F-350

[pappawheely]

The first question that pops into my head is, will that U-Haul box stand up to all the twisting and flexing incurred when 4-Wheeling? Aluminum is somewhat brittle, and I believe that whole box is put together with pop rivets.

Other than that, your plan sounds fine.

You are correct about the al-u-mini-um. That's why you use spring mounts. The box is actually held together by sex bolts. New concept drawing. Don't laugh at my photoshop skills. :mixed-smiley-030:

 

[patoz]

Don't laugh at my photoshop skills. :mixed-smiley-030:

At least you 'have' photoshop skills! unk03:

 

[Healeyjet]

I agree with Patoz, at least you have photoshop skills.

Is the area in black going to be storage boxes built in to a flat deck type frame which will carry the u-Haul box? If the frame you built had very limited flex and was on a three point mount to release it from the truck frame you may eliminate a lot of twist to the box.

Ward

 

[njtacoma]

Have you taken the uhaul off road? I mean not really, but found a ditch or loading ramp, something just to try to flex it and see what happens? this would give a baseline or the flex you might experience. Not suspension flex, but frame and box flex.

I like the idea of changing to this chassis, the battery locker/storage locker seems like it would work, keep the weight centered.

Would you need to move the wheel wells in the box since you are sliding it back? will they even be necessary with the planned changes?

 

[pappawheely]

I agree with Patoz, at least you have photoshop skills.

Is the area in black going to be storage boxes built in to a flat deck type frame which will carry the u-Haul box? If the frame you built had very limited flex and was on a three point mount to release it from the truck frame you may eliminate a lot of twist to the box.

Ward

Yes. I have a grey water tank that will mount under there on one side and I'm sure other items will find space there.

Have you taken the uhaul off road? I mean not really, but found a ditch or loading ramp, something just to try to flex it and see what happens? this would give a baseline or the flex you might experience. Not suspension flex, but frame and box flex.

I like the idea of changing to this chassis, the battery locker/storage locker seems like it would work, keep the weight centered.

Would you need to move the wheel wells in the box since you are sliding it back? will they even be necessary with the planned changes?

Right now the box is solidly mounted to the frame and the suspension will be changing drastically so that would not be a valuable test. The wheels/tires do not protrude into the box and the openings on the side are just cut into a flat panel so I can locate the axle anywhere. The Uhaul wheelbase is shorter than the F350. I could move it out to match the F350; it's a trade off between a shorter wheelbase for turning or less overhang in the rear. In any design scenario it's always a matter of compromise and priorities. I have looked at the structure under the box and it's possible to extend part of that structure to include the new storage compartment into the box subframe. That means I only have to create a flexible seal between the cab and the storage compartment to create a pass through.

 

[njtacoma]

that's right I forgot about the spring mounts on the box. Not any real value to the flex test.

Tying the box to the compartment makes sense, keeps that portion all rigid.

 

[HMT]

I think I would keep the crew intact and search for another 4x4 donor and/or the parts to build the dream rig. Less (or no) downtime and you then have a backup with the crew or the crew could be sold intact to recover costs.

 

[rayra]

I think I'd rather press on with the original plan and beef up and add additional cab mounts. And keep the crew cab. An RV AC unit on the box, coupled with a rear-window pass-thru could even aid in the cab cooling. Electric fans on the AC condenser would be in order, if you don't have them already. And fabricating box mounts on the truck frame should be an easy job, set a new level and weld on the necessary square tube steel as spacers. You could even 'steal' a few inches in that process and gain more under-floor space for your tankage.

The big stiffer heavy frame might not be the thing to go for. That box is never going to hold the mass cargo weight originally intended as a U-Haul, thus the frame becomes overkill for your project. Re-consider what (if anything) you'll be losing by switching to the Uhaul as the chassis. Loss of the crew cab for starters.

Maybe reconsider the practicality of wheeling with that big box in the first place, and consider going with your bigger live-in rig as your on-site live/work space, but go with something light, nimble and towable as your scoot when you are leapfrogging around a course.

I guess what I'm trying to say is step way back and re-evaluate the whole project, rather than making a series of problem-solving decisions that take you astray from your original plans.

 

[pappawheely]

I think I'd rather press on with the original plan and beef up and add additional cab mounts. And keep the crew cab. An RV AC unit on the box, coupled with a rear-window pass-thru could even aid in the cab cooling. Electric fans on the AC condenser would be in order, if you don't have them already. And fabricating box mounts on the truck frame should be an easy job, set a new level and weld on the necessary square tube steel as spacers. You could even 'steal' a few inches in that process and gain more under-floor space for your tankage.

The big stiffer heavy frame might not be the thing to go for. That box is never going to hold the mass cargo weight originally intended as a U-Haul, thus the frame becomes overkill for your project. Re-consider what (if anything) you'll be losing by switching to the Uhaul as the chassis. Loss of the crew cab for starters.

Maybe reconsider the practicality of wheeling with that big box in the first place, and consider going with your bigger live-in rig as your on-site live/work space, but go with something light, nimble and towable as your scoot when you are leapfrogging around a course.

I guess what I'm trying to say is step way back and re-evaluate the whole project, rather than making a series of problem-solving decisions that take you astray from your original plans.

Trust me, I have over-thought everything on this project, :ylsmoke: Switching to the Uhaul IS my re-evaluation. We built a class 7 truck many years ago. We took the stock frame that was real flexey and added reinforcements to it. That thing just cracked and cracked. I want a stiffer frame. The wet noodle frame on the F350 is already tweaking the cab. Adding more mounts will not change that. I've been down that road before. Look at these two trucks. There is a reason why Earthroamer uses a 550 and not a 350.

 

[Sooper Camper]

To be fair, you're comparing an open c-channel frame designed before microprocessors to a hydro-formed and mostly boxed frame from the 21st century...

But you are correct, those frames are noodles. I think you are making the right decision, part of the reason I chose the 350 as my platform is that the 70's models use essentially the same frame as the u-hauls/Cab & chassis from the same era. In the 80s, they obviously streamlined and went to sharing a frame. I've heard the steel is thicker for the higher GVWs, but the cross section which is far more important stayed the same. Its amazing how many holes are drilled in those frames from the factory too. I spent an entire day welding up holes on my old Bronco after it had been through a few generations of lifts/solid axle swaps. If you can swing the standard cab, I think this is the smart choice. Less cab space, but more living space for the same (smaller?) overall foot print.

I saw the truck at KOH, it looks really good in person. I was working Sledge recovery on Friday, I drove the PolyP buggy. Didn't realize we were so close, but I was busy rock stacking for race cars lol.

 

[Korben]

FWIW I think you're setting yourself up for a lot of extra work, will miss the crew cab, and will find a lot of issues will pile up. Curious though, is that U-Haul F350 based or F-Superduty(F450) based, and which front suspension does it have, moonbeam leaf or TIB coil? I'm sure you've considered all the work of swapping everything and converting to 4WD but then there's a issues with it being a C&C frame. This will make nothing behind the cab swap with pickups. You've done all this planning and shopping based on the 37" pickup frame, going to a 34" C&C frame changes all that.
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I think a better way to go about it is to let it pivot, these frames are designed to flex(the U-Haul frame to) and it's a big part of your articulation, just let it happen, go with it. Solve the cab issues by changing the body mounts a bit. Do a short body lift and change the two rear corner mounts to one center mount, this will let the frame flex under the cab and not twist the cab. Then for the box, use the frame rails of the C&C frame it's mounted on now to make a pivot frame for the box IdaSHO style.

 

[pappawheely]

To be fair, you're comparing an open c-channel frame designed before microprocessors to a hydro-formed and mostly boxed frame from the 21st century...

But you are correct, those frames are noodles. I think you are making the right decision, part of the reason I chose the 350 as my platform is that the 70's models use essentially the same frame as the u-hauls/Cab & chassis from the same era. In the 80s, they obviously streamlined and went to sharing a frame. I've heard the steel is thicker for the higher GVWs, but the cross section which is far more important stayed the same. Its amazing how many holes are drilled in those frames from the factory too. I spent an entire day welding up holes on my old Bronco after it had been through a few generations of lifts/solid axle swaps. If you can swing the standard cab, I think this is the smart choice. Less cab space, but more living space for the same (smaller?) overall foot print.

I saw the truck at KOH, it looks really good in person. I was working Sledge recovery on Friday, I drove the PolyP buggy. Didn't realize we were so close, but I was busy rock stacking for race cars lol.

What a mess on Sledge. Who would have thought that the waterfall would be easier than the rock pile around the corner? Sorry we did not meet up.

FWIW I think you're setting yourself up for a lot of extra work, will miss the crew cab, and will find a lot of issues will pile up. Curious though, is that U-Haul F350 based or F-Superduty(F450) based, and which front suspension does it have, moonbeam leaf or TIB coil? I'm sure you've considered all the work of swapping everything and converting to 4WD but then there's a issues with it being a C&C frame. This will make nothing behind the cab swap with pickups. You've done all this planning and shopping based on the 37" pickup frame, going to a 34" C&C frame changes all that.
.
I think a better way to go about it is to let it pivot, these frames are designed to flex(the U-Haul frame to) and it's a big part of your articulation, just let it happen, go with it. Solve the cab issues by changing the body mounts a bit. Do a short body lift and change the two rear corner mounts to one center mount, this will let the frame flex under the cab and not twist the cab. Then for the box, use the frame rails of the C&C frame it's mounted on now to make a pivot frame for the box IdaSHO style.

The frame profile behind the cab on the C&C is taller than the f350 and the rails are flat and straight. I don't have to do anything besides adding spring mounts to make it work. That saves me hours of design and fab work and I know it will work. The Uhaul is 2WD with TTB. Because I have a shackle reversal kit from SORD, my springs are mounted with brackets that bolt to the frame on each end. Mounting the front suspension onto the Uhaul will be a bolt-on affair. I may even swap the front crossmembers (replacing the rivets with bolts) so I don't have to spend hours drilling new holes. The truck is plenty tall already, The Uhaul frame allows the box to sit low, that's what I want. To put it on the F350 I have to raise the box. Raising the cab too just increases the height of everything. You guys may have forgot, the Uhaul gives me 1800 more pounds of GVW. I will need that.



In my opinion, I think the three point system creates load points in the front and rear allowing the frame to flex in the center. That is my theory on why Hadley's frame cracked the way it did. With the simpler spring mount method, the weight is distributed along a greater length of frame rail while still allowing flex and articulation. I really value everyone's input on my decision making. It reminds me of the design reviews I had to go through when I was a design engineer. I miss those. We always said, if your design cannot withstand scrutiny, it's not ready for manufacture.

 

[rayra]

Good, then, all that matters is that you've considered all the trade-offs. It's all a customized project anyway, whichever path. I'd thought you were further down the mod trail on the crew cab, so switching over to the UHaul chassis seemed like it would be more work.

 

[Wilbah]

As someone purely sitting on the sidelines and offering no help at all I really appreciate all the thoughtful commentary on these varied subjects. I am learning a ton. I just wish I had something to add...but thanks for the education to everyone adoing to this. And with all the great pics thrown in throughout the discussion this is a really great thread!!

 

[Seabass]

I've been thinking about your build. I'm not jealous of your situation. I can see arguments for both scenarios. On the one hand, the U-haul truck already sports the box, and you're right about bolting the 4x4 hardware to it. It probably won't be that bad of a job. I've considered buying a two wheel drive dually with a crew cab and ordering a SRK and using my spare Dana 60 from my donor truck to build a swanky OBS hauler. I've read about the conversion from two to four wheel drive a bunch. Once you have the parts it can be done in a day. I know your worried about having enough GVWR to be legal and the box truck is gonna really help that out since it's got a higher one. That might be all the reason you need to keep the box truck right there. However, the crew cab is already a capable off-road rig. The frame can be dealt with in several ways. I once put a flat bed on a early nineties dodge D-350. It did not have a flat frame either. My solution was to lay a 8' long piece of channel next to the frame and scribe out the shape of the frame onto the channel. Then I cut that out of the channel and welded it on top of the frame. This made a flat frame from the back of the cab to the end of the chassis. I put the lip up, so I had a nice shelf for the bed to ride on. I basically built a new top for the frame. It was no taller at its highest point than the highest part of the hump in the chassis over the rear axle. I welded every inch, inside and out of the channel to the chassis. It wasn't that big of a job. Added maybe half a day to the whole project. To this day that truck packs tractors and bulldozers up and down the road. That was 15 years ago. When I put the flat on my work truck I simply used the proper sized spacers to balance it on the chassis and straps to attach it, but I wasn't overly concerned with flex tearing it apart. So, you can overcome the crew cab chassis. If you create a flat chassis it'll also add some strength too. Granted it will still flex. And big rigs are C-channel front to back. And they flex TONS with no issue. We currently operates several big trucks in our feed business and we are off road a lot. We run full lockers in all axels so our trucks are extremely capable in tricky terrain. Most of these trucks use a single point mount in the rear of the cab and two at the floor pan. One on each side. While the front two are hinged and the rear is an air bag you could fairly easily change your crew cab to a single mount in the center of the cab. There's a lot of metal back there and it wouldn't take a lot of plating, or bracing to beef it up. With the bed off you can access the area fairly easily. This is a mount I fabricated for a Mack that I took the sleeper off of. This is a factory mount with a pan hard bar on an International 9200. And any time I see a big truck chassis I'm reminded of my old Ford trucks. They are a lot alike. I also think you probably won't be jumping and pounding the crap out of your old crew cab as much once you get the box on.....this could help a little ! I've packed 20,000 pounds plus with both of my crew cabs. I know several other guys that have too. The frames are stronger than the flexing and twisting would lead you to believe. I've also mounted really long tanks to some big trucks, like 20' long and used the plates and springs to allow for flex. It works. I've currently got a M-923 military 5-ton with a 14' flat and a two thousand gallon tank strapped on it. I'm pretty sure it uses bolts and springs too to hold the bed to the truck. All factory. And it REALLY flexes when I go off in the fields. I actually rolled this truck last summer, it's a 932. Very fun. Any way. I wouldn't want to have to make your decision. But for me personally, I'd probably put the box on the crew cab truck. However, you certainly ain't going wrong by keeping it on the reg cab and swapping the 4x4stuff either. At the end of the day you'll do what works best for you. None of us posting here have to drive it, or live with it. Good luck.