FlashHole's M416 trailer Build

Flashole

Adventurer
I was lucky enough to find a M416 trailer on Craig's list. It was pretty rough, but solid enough to be well worth the $400 the guy was asking. I called about ten minutes after he posted the and wet to see it immediately. Good thing because the guy said about five people called right after me and offered to buy it sight unseen. He was a stand up guy and gave me first option to buy.

I've been looking at a lot of build threads posted here and some of you guys are amazing fabricators. My trailer build won't be that elaborate, but it will be done right and will be a nice trailer when I'm done.

I've been meaning to post this for a while, so the build is pretty far along. I'll try to update it as I proceed.

Here's how she looked when I bought her.
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As you can see, the tailight is broken. Bummer because I was hoping to re-use them. Oh well, I'm not trying to do a restoration anyway.
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All broken down ready to go to the sand blaster and then powder coating. I was surprised just how solid the frame was. Aside from some rust pitting on the tongue arms, there was no other real damage.
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Fast foward a few weeks and its back, and I have to say, it looks brand new. Looks a lot better than I was expecting.
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Now that the frame parts are looking good, the tube and fenders are off to the sandblaster and it's time to start putting the frame back together.
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I was planning on re-using the spring shackles, but the rubber bushings were toast and I couldn't find replacements. Plus, the grease nipples were pretty clogged and weren't replaceable. Morris 4x4 had new shackles for fairly cheap, so I just ordered new ones. The inserts were in good shape, so no need to fight that battle.
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The U-bolts that go around the tongue arms and connect the tub and parking brake were toast. The threads were rusted pretty bad. So off to the internet to find replacements, but after an exhaustive search, it appears that they are un-obtanium. Apparently, 7/16ths rod is not a common for U-bolts. Who knew?
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So now what? After much searching, I found a local shop that specializes in truck springs and they were able to bend a couple up for me. Cost me $12 bucks I think.
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While I was painting the freshly bent U-bolts, I went ahead and painted all the washers. I purchased all new hardware, but being the cheapskate that I am, I didn't spring for new washers. Stupid, I know, but a dollar is a dollar.

All painted up.
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Now for the Axle decisions. The old axle was in decent shape, but lik everyone else, I wanted to run the same size tires and wheels that are on my Jeep. That means either adapters, or a new axle. Since the hand brake was already missing and I wasn't doing an accurate restoration anyway, a new axle was a no brainer. For what it would have cost me to replace the hand brake mechanism, rebuild the brakes and bearings, I was able to purchaes a whole new axle with electric brakes. A quick call to Red Neck trailer supply and a 4 day wait I have a brand new axle with a 5 on 4.5 lug pattern and electric brakes.

Came with a crappy paint job, so I stripped it down, primed and rattle canned it. Had I had it sooner, I would have had them powder coat it. But, I'm making this up as you go along, so it is what it is.
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New axle U-Bolts meant that the old plates with the shock mounts no longer fit. I decided that instead of modifying the old plates, it would be quicker to just cut the old shock mounts off the old plates and weld them to the new plates. Easy enough.
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Picked up a couple new wheels from a local supplier. Posted an ad on the local jeep club's forum looking for a set of used tires. A guy actually gave these to me. They are 33"x10" instead of 33"x12", but they were free and in great shape, so they got mounted and will ride for a while.
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The old wiring was shot, so I ran all new wires and connected up some cheap Harbor Freight tail lights. May still replace them with something a little better in the future.
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The frame is all but done, so a quick test run through the neighborhood was warranted. Seems to tow pretty well.
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Time for the hard work......Fixing the Tub. But, it's work I will actually enjoy. I enjoy fabricating, body work and painting, but I've never really enjoyed mechanic type work. I just don't get much pleasure un-bolting and re-bolting stuff.

The tub came back from the sandblaster with a coat of flat powder coat on it to keep it from rusting while it sits.
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The tub had 10 recessed tie-downs welded to the sides. I was worried about rust underneath, so I cut them off prior to going to the blaster. Sure enough, there was some pretty deep rust. I liked the idea of recessed tie-downs in the bed sides, but they were just plain ugly. Sucks that there are 10 4" holes in the tub, but they had to go.
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Flashole

Adventurer
I was hoping to be able to save the floor, but it came back from the blaster looking like swiss cheese, so it will have to go too.
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So, I broke out the plasma cutter and 10 minutes later, the floor was gone. I learned early in life to buy lots of tools and always keep them. The plasma cutter was worth it's weight in gold today.
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The floor was still pretty solid, but just had to many pin holes to warrant spending the time trying to weld them all up. Since is was generally solid, I was able to leave a lip all the way around to lay the new floor on.
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Made careful measurements and had a local sheet metal company cut me a sheet of 12 gauge sheet metal to fit. Luckily, it dropped right in and fit like a glove. Made sure the tub was still square and welded it in. I'm a lousy welder, so I spot welded the top every inch or so, and on the bottom, I spot welded it every 2 inches or so.
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Then I flipped it over, laid downs a few coats of self etching primer and seam sealed around the joint.
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I had planned on using Raptor Liner, but the local place that stocks it said that they hadn't re-ordered because they changed the formula for the hardener and were having problems with it. Don't know how true that is, but that's what they told me. They did have a product called Armor Liner which they said was just as good and possibly better. It was about $5 cheaper, so i thought what the heck, I'll give it a try on the bottom. If it doesn't perform, I'll use something different for the interior of the tub.
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Hard to tell, but it laid down well, and went on really thick. It's dried hard as a rock too. I suspect that this is pretty good stuff.
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On to the patching up the holes from the recessed the tie-downs.

Cut all the holes to square and made them big enough to eliminate the rust.
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Cut patches from 16 gauge steel and welded them in. Also welded up all the reflector holes and the holes from the data plate as well as any pin holes I found while I was at it. The last thing I will do is go back around and do final welding of any pin holes that I may have missed.

Don't make fun of my welds. Welding has to be one of the most un-natural things I've ever tried to do. Basically, I suck at welding, but have mad grinding skills, so all will be well.
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On to the tailgate.

I spent a lot of time considering just how I was going to do this. In the end, I decided to just start welding and cutting and see how it came out.
Started with a piece of 1"x1" thin walled tube and welded it across the bottom.
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Then, framed up the rough opening.
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Also welded in some braces on the inside. Am worried about losing strength in the tub when I cut out the opening for the tailgate.
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Next, I welded in the framework for the actual tailgate.
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Once I did that, I used a Sawzall to cut in between the framed opening and the tailgate frame. Removed the tailgate and cut the excess sheet metal away.
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Welded on some small barrel hinges that I picked up from a local steel supplier. Again, don't laugh at my welds. They are ugly, but they aren't coming apart any time soon.
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That's as far as I've gotten so far.

Things still to do:

Locking latch system for the tailgate.
Final welding and grinding
Final body work
Prime and line the the interior of the bed
Exterior paint
Tongue box/inverter/battery/plug-ins etc..
lid
Any other modifications to carry fuel cans, propane tanks, generator, water etc.... Don't know how carried away I will get?? I guess time will tell.

If you guys have suggestions or critique, I'd love to here it. And I will try to update any future improvements.
 

Mark Harley

Expedition Leader
Great work,
"Your welds look better than my bird poop lines"

The frame turned out well.
Will you be extending the tongue?
 

Flashole

Adventurer
Great job and well done! :beer:

Just one question: why do you keep the tub?

Good question. Seemed easier in the beginning, but in hindsight, it might have been quicker and better to just fabricate something. But in reality, what I should have done was to spring for a new one. I think I saw them for $950 somewhere. If shipping is reasonable, that might be the way to go if you like the look of the M416, which I do.


Great work,
"Your welds look better than my bird poop lines"

The frame turned out well.
Will you be extending the tongue?

Maybe in the future. I definitely see the advantage to having a longer tongue. I think it will boil down to whether or not I hate the Pintle hood style hitch. If I do, I will probably go with something like the max coupler and at that point I think it would be wise to just extend the tongue while I was at it. It will also depend on how I end up using the trailer. Hopefully it will see some time off road, but I suspect that it will see more use as a utility trailer than anything else. Or, I may just sell the thing when I'm done. We'll see.
 

JKJenn

Adventurer
Great job! How are you planning to implement the lock? I am looking to install a lock on my m416 tailgate, too.
 

Arlo

Adventurer
Seemed easier in the beginning, but in hindsight, it might have been quicker and better to just fabricate something. But in reality, what I should have done was to spring for a new one. I think I saw them for $950 somewhere. If shipping is reasonable, that might be the way to go if you like the look of the M416, which I do.

The M416 design is way cool, unique and well known!
But following the function, it might be serious to change the form. And the material!

I prefere aluminum. Glued and riveted.

Just like this:

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Maybe it's just a Jeep thing to keek the old style? :coffee:
 

Flashole

Adventurer
Great job! How are you planning to implement the lock? I am looking to install a lock on my m416 tailgate, too.

I've been putting a lot of though into it and I think for the latch, I am going to order a couple of these weld on slam latches. I think the style fits the trailer really well, and they should be rugged enough to handle abuse. Plus, I like the idea of being able to close the tailgate with one hand.

As for the lock, I think tabs and a padlock will have to do.

Edit....I guess it would help if I added the pic of the latch.
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Last edited:

Flashole

Adventurer
I decided that I needed to patch the ends of the square tubes and top rail that I cut to make the tailgate. Pretty simple project.

Used a circle template to trace the right size circle onto a piece of sheet metal. Then just used the bench grinder and a pair of vice grips to grind it to fit.
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Then it was just a matter of welding them up and grinding it down.
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The square tubes were even easier.
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Now that pretty much all the welding is done, it was time to grind all the welds down from all the patches. Man I hate grinding! It's just not a fun thing to do. No pics of the grinding process. I'm sure you all can imagine.

Now, the big question. How straight do I make the body? I had to patch ten holes, so at the very least I will need to straighten those areas. My plan all along has been to do as little as possible. But the thing is, the difference between a fairly straight tub and one that looks like it's been through a war(which I believe this one has) is time and about $30 worth of additional supplies. I really hate to spend all this time, effort and money only to screw up the end game by being lazy. So, I've been spending quite a bit of time this week making it fairly straight. It will never be perfect, but it's going to be a lot straighter than when I started.

Here's a little tutorial for those that have never worked with body filler.

The panels that had the recessed tie downs are pretty warped up. Not sure if it was from the previous use of the tie-downs, or the panels just warped up when i welded in the patches. Either way, they are pretty warped up. First, I straightened them up the best I could with a body hammer and dolly. Then I grinded the entire area down, so the filler would have something to stick to.
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Then I mixed the filler. I use Evercoat brand filler. Always mix more than you will need. I'll tell you why later.
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I put a really thin coat on first pressing really hard to squish the filler down into the grinding cuts. Then, I put it on really thick and as straight as possible. I don't worry about putting it on thick because most of it just comes right back off. The first coat or two are when you make it straight. The rest are just filling of scratches.

First coat
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Once the filler sets up to about the consistency of cheddar cheese, you can grate it off with one of these. I have no ideal what it's called, but I've always called it a cheese grater because that's pretty much what it is. You just grate the filler off as straight as you can. This is when you can tell where the low spots and high spots are.

You can already start to see where the low spots are.
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All grated off.
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Here are a couple of high spots(eye brows). Normally, I would tap down the high areas with a body hammer and then do it again until the panel is completely straight. This particular area is under the fender, so i'm not getting carried away.
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Another couple areas.
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After the panels are as straight as I'm going to make them, I will do another thin coat of filler and block it down with 80 grit paper. Up until now, I've been mostly using the cheese grater and a block with 36 grit paper. After that, I will will use a light weight polyester paste to fill the final sanding scratches and block it again with 180 grit paper. Finally, I will prime it and once that's dry, I will block it down again with water and 240 grit. After that, it will finally be ready to seal and paint.

I mentioned earlier that you should always mix more filler than you need. Here is why.
Always bury your spreader in the left-over filler.
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Because when you pop it out, it's clean. Other wise, you have to scrape the filler off and it will quickly ruin it.
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TheJosh

Explorer
Beautiful job so far!! Love how you did the tailgate and I look forward to seeing how you will incorporate the locking pins

Sent from my Nexus 4
 

TheJosh

Explorer
For the tailgate, are you planning on putting some sheet metal on the exterior to box it in and to clean up the look of the gate?

Sent from my Nexus 4
 

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