Datsun Truck Bed Trailer

[3rd_Degree_Adv]

I've been kicking around this idea for a while and stumbled across this little gem on FB marketplace. Picked it up for $200 & I have a lot planned for it. First off, rebuild and extend the tongue. Secondly, have a custom "raised" axle built to accommodate larger tires. Third, fab up a rack for a RTT. I'm also planning on applying bedliner over the entire bed, but that'll be after all the fab work gets done. Any advice along the way is greatly appreciated as this is my first trailer/overland project.

 

[Anak]

I would say you are on the right start with planning to rebuild that tongue. That arrangement doesn't look particularly strong. Those diagonals need to extend substantially farther back and tie into the frame in more than one place.

When it comes to a rack for a RTT I would consider some bracing for support. I would not trust those bedsides to support much weight. Those trucks were pretty light duty.

 

[3rd_Degree_Adv]

I would say you are on the right start with planning to rebuild that tongue. That arrangement doesn't look particularly strong. Those diagonals need to extend substantially farther back and tie into the frame in more than one place.

When it comes to a rack for a RTT I would consider some bracing for support. I would not trust those bedsides to support much weight. Those trucks were pretty light duty.

Yeah, the current tongue arrangement is terrible and already bent from overload. As for the RTT rack, I won't even try to tie into the sidewalls, it will be bolted through the truck bed and into the frame underneath.

 

[Jeremiah Johnson]

Mine was free! Ha Ha I have done this mod already and wouldn't mind sharing pics and notes. I've meant to make it a write-up but haven't had the time through the summer and fall. I reworked the tongue as it was cobbled together by some old farmer. I did an over-axle lift and that made plenty of room for 31" tires and lots of ground clearance. I don't think you'd want to go higher because I feel you'd be getting into unstable conditions. My trailer looked exactly like yours and with the over-axle lift and the bigger tires I probably gained 10" of lift at the bed, about 5" of clearance under the differential, and over a foot at the tongue after modifying that too.I've got a little patch of trees on my property and I was dragging the trailer out on the ground before all the modifications, now even with a very heavy load of oak firewood the trailer off-roads like a champ. I also gutted and light-weighted the axle, removing unnecessary items like the pinion shaft, ring gear, brakes, and some odds and ends welded to the frame. I can wheel it around by hand now, it's no wheelbarrow but it is very lightweight. I am going to put shocks on it, doing 55 in the mountains and going from one corner to the next with the trailer loaded I can see the trailer lean and just to satisfy my OCD (undiagnosed) I'd like some shocks to control that sway a bit. It tracks straight, doesn't wander, or wobble, but empty it will hop pretty good over rough road and speed bumps because it's so light.
This was a pretty good load but I've since hauled a much heavier load of oak that had the leaf springs just past flat, putting a slight recurve in them. This trailer seems to handle better when it's loaded down like that. I added the square tube from an old receiver hitch off of a 3/4 ton pickup so I could use the bike carrier. We've tied them on top of the load for a few years now and this is a lot nicer and requires much less head-scratching.

I didn't do anything to the body yet, had to abandon this project and get my summer chores done. It was a 72 Ford Courier, Mazda built the axles for them, same axle as the B-series pickups. The 6x5.5" lug pattern let me use any 6 lug Toyota wheel.

I worked in a platform for our big cooler with a big plate in the front and two on the side to keep the cooler situated and there are tie down points for two straps to go over the top and hold it down. This is the handiest thing about the trailer, access to cold water and snacks on the road, and you're not taking up walking room in camp because it stays on the tongue of the trailer.

 

[3rd_Degree_Adv]

Mine was free! Ha Ha I have done this mod already and wouldn't mind sharing pics and notes. I've meant to make it a write-up but haven't had the time through the summer and fall. I reworked the tongue as it was cobbled together by some old farmer. I did an over-axle lift and that made plenty of room for 31" tires and lots of ground clearance. I don't think you'd want to go higher because I feel you'd be getting into unstable conditions. My trailer looked exactly like yours and with the over-axle lift and the bigger tires I probably gained 10" of lift at the bed, about 5" of clearance under the differential, and over a foot at the tongue after modifying that too.I've got a little patch of trees on my property and I was dragging the trailer out on the ground before all the modifications, now even with a very heavy load of oak firewood the trailer off-roads like a champ. I also gutted and light-weighted the axle, removing unnecessary items like the pinion shaft, ring gear, brakes, and some odds and ends welded to the frame. I can wheel it around by hand now, it's no wheelbarrow but it is very lightweight. I am going to put shocks on it, doing 55 in the mountains and going from one corner to the next with the trailer loaded I can see the trailer lean and just to satisfy my OCD (undiagnosed) I'd like some shocks to control that sway a bit. It tracks straight, doesn't wander, or wobble, but empty it will hop pretty good over rough road and speed bumps because it's so light.View attachment 122336
This was a pretty good load but I've since hauled a much heavier load of oak that had the leaf springs just past flat, putting a slight recurve in them. This trailer seems to handle better when it's loaded down like that. I added the square tube from an old receiver hitch off of a 3/4 ton pickup so I could use the bike carrier. We've tied them on top of the load for a few years now and this is a lot nicer and requires much less head-scratching.
View attachment 122337
I didn't do anything to the body yet, had to abandon this project and get my summer chores done. It was a 72 Ford Courier, Mazda built the axles for them, same axle as the B-series pickups. The 6x5.5" lug pattern let me use any 6 lug Toyota wheel.
View attachment 122338
I worked in a platform for our big cooler with a big plate in the front and two on the side to keep the cooler situated and there are tie down points for two straps to go over the top and hold it down. This is the handiest thing about the trailer, access to cold water and snacks on the road, and you're not taking up walking room in camp because it stays on the tongue of the trailer.

Nice! Thanks for the info. I've been thinking a hitch on the back would be nice to have for hauling bikes or recovery.

 

[Jeremiah Johnson]

Nice! Thanks for the info. I've been thinking a hitch on the back would be nice to have for hauling bikes or recovery.

I have gobs of pictures of the fabrication and such if you want to know how I did anything, or what something's supposed to look like when you're putting it back together.

 

[3rd_Degree_Adv]

Here's my plan for the tongue frame. This should put my hitch point 48"-50" from the front of the toolbox. I want to be able to interchange the hitches (go from a 2" ball to a lock n' Roll easily) so I plan it incorporate a 2" receiver tube at the hitch. I've never done this before and I'm not an engineer, so please let me know if you see something that needs to be changed or if there is something else you would include. Thanks!

 

[Jeremiah Johnson]

The reach on my trailer is 1/4" wall 2x2" tubing and it's not flexing under load or anything. I really wanted to be able to turn past 90 degrees, so I left that reach long enough to do just that. My Brother says I'm an idiot and if I've gone 90 degrees it's time to stop! lol I use that turn radius all the time though, a small trailer is so damn handy, no sense hampering it with limitations.

 

[Jeremiah Johnson]

I would shorten up that 40.94" measurement by something like half for turning clearance, other than that it looks good.

*Also, if you could shove your new steel into the pickup frame it would make a more secure connection. If your frame is like mine, I had a beefy outer C-channel the factory boxed with a lighter guage C-channel on the inside. That inner C was hard to weld to for my skill level.

You'll probably want to begin frame modifications just immediately ahead of the front spring hanger. I didn't see any lift to be gained behind that point and figured I might as well leave those spring hangers alone.

 

[3rd_Degree_Adv]

Thanks for the input Jeremiah! I hadn't even thought about turning radius (especially on a trail). [emoji2357] So here (pink) is what the front tongue would look like with the angled pieces set at 24" of straight tongue out front. The more I think about it the more I like this design.

 

[Jeremiah Johnson]

Thanks for the input Jeremiah! I hadn't even thought about turning radius (especially on a trail). [emoji2357] So here (pink) is what the front tongue would look like with the angled pieces set at 24" of straight tongue out front. The more I think about it the more I like this design. View attachment 122365

That looks good to me, it gives you a bit more reach on the tongue. The way I made sure I could go past 90 degrees was measure from the ball hitch to the corner of the bumper and that distance is the length of my tongue forward of all supports.

 

[3rd_Degree_Adv]

That looks good to me, it gives you a bit more reach on the tongue. The way I made sure I could go past 90 degrees was measure from the ball hitch to the corner of the bumper and that distance is the length of my tongue forward of all supports.

That's exactly what I did. My jeep bumper is pretty narrow so 24" is just about right for 90°. I'm also planning on mounting a propane bottle on the center of the tongue, in front of the toolbox, so i don't want to bring those angled pieces back to far.

 

[Jeremiah Johnson]

That's exactly what I did. My jeep bumper is pretty narrow so 24" is just about right for 90°. I'm also planning on mounting a propane bottle on the center of the tongue, in front of the toolbox, so i don't want to bring those angled pieces back to far.

It's hard to tell in my last picture but I'm actually only 90 degrees there and have about 4 more inches before I touch. You can basically jack knife the trailer as far past 90 as your stinger is long. That's just a bit of peace of mind and makes it much easier to back up solo. I know I can go 90 and beyond so I can always tell if I'm about to cause damage rather than wonder and getting out to look every inch or two of movement.

 

[Anak]

Thanks for the input Jeremiah! I hadn't even thought about turning radius (especially on a trail). [emoji2357] So here (pink) is what the front tongue would look like with the angled pieces set at 24" of straight tongue out front. The more I think about it the more I like this design. View attachment 122365

I would consider changing the tongue design to be more like the design used in professionally built trailers (if my description doesn't make sense here, then you may want to simply go look at a few trailers, then you will understand what I am trying to say): Take that upside down "V" (either blue or pink) and rather than connect the ends of it to the very front of the trailer, instead extend it back to about where those two purple boxes are (one of them is next to the "I-4" on your drawing). Doing this will allow you to weld that upside down "V" in two places on each side: At the front crossbar and near those purple boxes. That will be substantially stronger.

On your current design I expect all the framing is on one plane, with the possible exception of the bar with the coupler on it.. If you switch to what I am describing then the rectangle of the frame will be in one plane, but the upside down "V" of the tongue will be in a lower plane, including the bar which has the coupler on it.

I hope that all makes sense. If you can't make heads or tails of it and can't find examples of it let me know. Worse comes to worse I can try to find some pictures for you.

 

[3rd_Degree_Adv]

I would consider changing the tongue design to be more like the design used in professionally built trailers (if my description doesn't make sense here, then you may want to simply go look at a few trailers, then you will understand what I am trying to say): Take that upside down "V" (either blue or pink) and rather than connect the ends of it to the very front of the trailer, instead extend it back to about where those two purple boxes are (one of them is next to the "I-4" on your drawing). Doing this will allow you to weld that upside down "V" in two places on each side: At the front crossbar and near those purple boxes. That will be substantially stronger.

On your current design I expect all the framing is on one plane, with the possible exception of the bar with the coupler on it.. If you switch to what I am describing then the rectangle of the frame will be in one plane, but the upside down "V" of the tongue will be in a lower plane, including the bar which has the coupler on it.

I hope that all makes sense. If you can't make heads or tails of it and can't find examples of it let me know. Worse comes to worse I can try to find some pictures for you.

Anak, that makes total sense to me and I thought about doing that for structural integrity of the tongue. However, there are 2 reasons I'm not doing that; 1) this trailer won't be loaded with enough weight to need that much structural rigidity & 2) primarily, that would lower my hitch to far (even with me raising the entire trailer with larger tires). If i keep the hitch centered in the framework (on 1 plane), that keeps the hitch higher and more level with the tow vehicle.

 

[Anak]

With those considerations I would then think about adding some triangular (more or less) steel plate gussets on the insides of those joints.

Keep in mind, weight is not your only consideration if you are planning to take this off-road. Every rock and bump is like a hammer strike on all the joints. Eventually those add up and take their toll.

 

[3rd_Degree_Adv]

With those considerations I would then think about adding some triangular (more or less) steel plate gussets on the insides of those joints.

Keep in mind, weight is not your only consideration if you are planning to take this off-road. Every rock and bump is like a hammer strike on all the joints. Eventually those add up and take their toll.

Yep, I was thinking about gusseting all the joint welds. Figured it might not be necessary, but going a little overstout definitely won't hurt anything.

 

[3rd_Degree_Adv]

Got a few things done today; 1) removed the bed. 2) cut off the old bent tongue. 3) cleaned up the welds from the old tongue. 4) started to fill in the holes from the old tongue.

Unfortunately I ran out of wire in my welder and I don't have the adapter for the 5# spool. So I'm going to have to hold off a few days before I can finish fixing these holes.

Also, I'm going have to wait till after payday before I can buy the steel to start extending the frame and building the new tongue. So going to be a week or so before any more updates unfortunately.

Unless I start wire brushing the bed and painting it...I could be doing that. LOL

 

[Jeremiah Johnson]

Are you thinking about lightweighting the axle as well?

 

[3rd_Degree_Adv]

Are you thinking about lightweighting the axle as well?

Yep! I'm having a 4 inch "raised" axle built by a local shop. Should drop roughly 100# off the weight and I can still use the stock suspension setup.