trimster

Got it. Thanks. Brain fart...or old fart brain.

And I have a respirator for that....

Behind the bumper is this 4x4 tube that runs through the bumper mount, to both sides of the frame extension. It also supports the receiver hitch. I have to guess the fabricator put it in because it might be required? for rear impact. I forgot to ask. Can it be cut off, more or less, flush? It would allow me to put in a bigger storage box behind the wheels.

So, second draft of the bed design...without the beaver tail. Looks like it's do'able with the hitch height. I can always raise the hitch if needs be. This gives taller rear storage cabinets. I'm thinking 2 roll-out drawers on the passengers side. The drivers side will have the generator on a rollout. These cabinets are 30" deep, close to 30" tall and 20" roughly, wide. Going to check if I can have them power coated black on the outside. Painted white on the inside. Still working on a way to allow for most of the bed to be removed in one piece should that be needed. The ramp boxes cut through the bedframe and the outside bed rail, so there's no continuous piece of steel front-to-rear. With 3 D-ring pairs spaced down the bed It could allow for weight bearing points that would take the stress off the weaker points. Still noodling. When I have the bed mostly framed up, I'm taking it to the fabricator for them to build and put in the ramp boxes, rear tool boxes, and possible skirting around the tires. They'll also cut the top deck plates. I'm screwing those down so they can be removed if needs-be. With the weather hovering around the 40's (on a sunny day), ya, welding and drilling just ain't in the cards. But I'm building brackets and such in the shop. I need to fabricate a wiring harness for the 'chicken' lights that will go down both side and the read of the bed railing, power to possible lights in the tool boxes, and heavy lines back to the cab from the generator for an inverter, etc. Oh, where do I look for wheel chalks? Suggestions.

What's the bed height?

In the HDT resources area (pinned on the first page) is a checklist you might want to look at. I downloaded it and made changes (made it more readable, added stuff that was important to me, etc.). It's 8+ pages. It took me several hrs to go over the truck with this checklist. I missed one (or rather ignored one) of the line items and it cost me several hundred dollars. When checking the tires, I did not check the load rating on the steers. One was G and the other was H. When I had the state inspection done on the truck, I got gigged (failed until fixed) on this. Hence, a perfectly good tire had to be replaced on my dime. Here's a link to the updated version of this checklist. Hope it is helpful. Check list here Bob

Steve from So Cal mentioned putting braces under a few cross members to help with flex. Engineering wise, how strong are the 2 x 2 ribs? From the point where they connect to the frame-rails, to the outer edge of the bed will be 30". Would it be stronger to use 1x2 C-channel or stick with the 2x2 thick wall tubing? The outer bed rail will be 2x4 C-channel. Haven't purchased the materials yet. Thought it might be a good time to rethink some up-coming decisions. Bob

I paid for an independent, better-than-DOT inspection ($230 as I recall). It included pulling the engine computer codes. Found some things that needed addressing by the seller (dealer in my case). The big problem was front brake shoes that were badly fractured. Well worth the money spent. If nothing else, trained eyes gave peace of mind. Bob

I've been looking at these. Not sure if they are replacement covers or 'slip-covers'. The latter would not work for me. https://www.raneystruckparts.com/volvo-vnl-vnm-2004-2018-premium-factory-seat-cover/?gclid=CjwKCAiAoOz-BRBdEiwAyuvA6yetN-lvkCELnnRGDhF9IuFC5MQopCyRjISEEv20rPDVLu_Tu06yzxoCClQQAvD_BwE In my truck, the passangers seat is in good shape. The drivers...660k butt-miles. Serviceable but the butt foam is ready for replacement. I have worked out a process for motorcycle seats (that makes them 12hr ride comfortable) that I'm going to try on the truck. I need to dig in and see what's under the cover. Bob

Ahhh. New Mexico. Poster child for crappy roads.

So when completed, the mud flaps will be tucked between the tires and a box behind them. Maybe a couple of inches clearance. The box should keep them from sailing yo much. At least that's the plan.

Understand about the rectangular tubing. I was figuring that a 20" span of thick wall 1x4 would be fine between the cross members and there's a plenty of them. The angle would be cheaper and less welding. I'm not sure I can put struts from some kinda frame drop structure to the underside of the x-members. Maybe one between the front 1/4 fender and the fuel tank and another at the back of the frame. No way can I get one between the tires/axles unless I cut huck bolts to get access to the truck frame. I understand the reason or desirability to put in the struts, not sure I have seen them on most beds I have looked at. Maybe I missed them. I did consider making the cross members 1x2 C channel. It's just a lot of work if you need to put in a piece joining the space between the cross members. Square tubing is easier...for me to deal with. I would like to see photos of a bed installed with the struts. Ya, the deck could be built in 2 section breaking right after the front ramp box. I'd just double up the 2x2 at the joint and bolt through them.

"Removable" That means they would be bolted to the bed frame rail and just rest on the truck frame rails? Or maybe bold to those as well? Wonder if it's worth all the drilling, welding in tabs, etc. Great idea however. I'm going to noodle on this one.

As you get your head wrapped around the rig and figure stuff out like how it drives, what you have to do to feel comfortable moving down the road, I might suggest some mirrors on the hood. Ours came with them and they are key to seeing idiots in the blind spots. Just when you think you are clear to move over, I've glanced at those and found a small car or motorcycle that would cause things to end badly with the lane change. Didn't have them on our MDT. Would not be without them now. Enjoy the rig.... and all the beer-can-in-hand rubber necking when you pull into the campground.

The cross supports where the weight of the vehicle will set is a good idea. I added them to the drawing. They are 1x4 tubing. The reason for the tubing over angle as you did...I am screwing the deck plate down. That way I can remove it to service stuff below a bit easier. The front (right most in the drawing) ramp box is directly over the existing steps to the back of the truck. The other side of the car/trike wheels will ride on the cross member just to the right of the middle ramp box. In fact, it will be right on the cross member.

Ya, I need to match the C-channel thickness so it will look seamless when welded, ground flat, and painted. The place where I get my steel is good about helping us newbees with stuff like this. I bring in drawings and explain, and they make-it-so (as Picard would say).

Question to you welding/design pros. Looking at the drawings I put up in the first post, and specifically the edges of the bed where the ramp storage boxes are. The bed frame outside rail is 2x4- C channel. The ramp boxes cut into this rail leaving 1" across the top, of the original 2x4 steel. I don't have a way of cutting this kinda notch (3"x 22"). So I am thinking about creating what you see in the drawing. The C channel gap is joined with 1"x2" angle to crate the top edge, and then backed with 1"x4" rectangle box. The angle and box are welded to the 2x2 ribs running across the bed. Will this construction support a Smart car driving up on the bed? I will have the aluminum ramp support brackets on the edge of the bed, which will help distribute the load a bit more, across the welded seams. Thoughts on this are appreciated.

So, there were two mfgs of this style of spring/suspension units. The ones on my hitch went out of business...at least they do not offer them anymore. The folks at Sumo have on their self in their R&D area, the springs in my hitch. Well, not mine, but they got a few to see what the competition was up to. They are the same technology. The Sumo folks have a pretty cool kit for trailer suspension as well. And kits for the front axles on our HDTs. What I will be doing is buying a kit for a Ford 450 front suspension. It has a bonded mounting plate on the bottom that I need to remove and then bore a 1" dia. hole into the bottom of the spring, which sets on an alignment block in the hitch. The spring dia. and height are workable in the hitch. They have several similar springs with different weights (resistance specs). The ones in the hitch now are about 1500# each. But that 'resistance' spec is kinda fluid. It's not linear like a traditional steel spring. And the spec/rating is at 50% compression. So the pair I am looking are rated at 4000#...as a pair....not individually. My roughly 2800# pin weight will compress these about 30% or a bit more. This will give the hitch more bottoming-room which I lack now. Not sure when I will get these. It's on the list. Building the bed comes first.

Ya, that's kinda what I did. I raised the adjustments of the hitch and dropped the pin box down. It now pulls level. Putting riser-blocks under the hitch, to elevate it seems like a good plan. I just corresponded with the folks who produce Sumo Springs and they have these style suspension springs in densities higher than what's offered with the hitch. The next step up is 4000# at 50% crush. I'm thinking 2 of those placed in the outside positions might mitigate how much the hitch squats. It would give me load head-room if needed. Right now, the hitch when loaded, has 1.5" of downward travel. All that against a suspension (the springs) that are very close to full compression, appearing to be a solid to the movement. I need to get range of motion back. I also plan on adding vertical plates between the sides to stiffen those.

Trailer is level on the Volvo. I had to lower (extend down) the pin box as far it would go and raise the hitch by one increment. The hitch can be raised another 2.5". There's bolts on the side of the side-plates that hold the lower spring tray in place. Moving those up would be the same as putting a block under the tray. On the MDT (shown in the photos), I had to have the hitch in its lowest position to get the trailer level The issue with these springs is that when the trailer is hooked up and running down the road (earlier photo) the springs are at about 70% compression. Should be closer to 60%. At 80% they start to appear to the load as a solid object. That's why I am going to get 2 stiffer springs for the outside positions. The 'relief' is 2" over the run of the pin box arm. The pin height, when running level, 45".

Here's the only nearly-side-on photo I have. This shows it with no load on the hitch...springs fully extended.

Absolutely. I'm getting two new springs that are stiffer. Should be more like a progressive load-spring arrangement.

Noteven: So I kinda did that 'line projection' activity and found that unloaded, the hitch is 2" above the planned bed height. My concern is when loaded, it squats 2"+. The suspension, as seen in an earlier photo, is not air driven so pumping it up to maintain ride height is not an option. The photo below shows it on the road when mounted to the MDT we had. But I do have 2 options and one is not a good plan due to the design (or lack thereof) of the hitch. I can raise the suspension several inches by adjusting the tray that holds the suspension 'air springs'. This increases the side-to-side forces through leverage. The side plates on this hitch are already marginal. So I hesitate to move the load-point up. The second, better, plan would be adding box tubing under the hitch. Thru-bolt it to the base mounting plate. If I raised the overall hitch height 3", the top of the hitch would be flush if not a tad higher than the deck under full load. I'd feel a lot better about that scenario. Would it then be to high to allow for a hitch hole cover to fit when the head is removed? Should (nebulous word). I can figure that out easily.

Interesting. But can I leave it as-is, build a flat deck and still have everything clear when doing sharp turns?

This is really good to see and know. Thanks. Flat deck is easier to build. However, my hitch suspension squats 3" when the trailer is hooked up. Right now the top of the hitch is 2" above projected deck height . With the trailer on-hook, the top of the hitch will be below the top of the bed. Yes, the pinbox does slope up about 2" over its length. Maybe I am still concerned that the pinbox will not clear when jack-knifed. My shot backing into our yard, does require a near 80 degree backing turn. Maybe I am not visualizing this properly.