My "New" Willy's II Trailer Build

slimtwo

Adventurer
Howdy everyone! Well I'm getting ready to start a new trailer build. I planned on building this trailer 10 years ago, but as fate would have it, I stumbled across an old MBT Willy's military trailer that someone was selling, and I decided to take the easy way out and turn that into an adventure trailer. 10 years later, after modifying and using my current trailer, I have decided to get back on the ground up build. I am modeling my new trailer after the Patriot X1 camper. It will be approximately 11 feet, tongue to tale, and the width of my TJ (72 inches). It's gonna have independent airbag suspension, using an axle from a local trailer dealer, with electric brakes, and 5 on 4 1/2 hubs, and tires and wheels to match the Jeep. I've got the axle, and I have purchased all the steel to get started. I plan on posting pictures of my progress as I go, however, I sometimes get caught up and forget to take pic's.
Here is a diagram of the frame , although it is still evolving.
frame 3.png

I hope to get started in about a week or two.

Until then, happy trails everyone!!!
 

sycboi

New member
Very nice. I am doing something similar to tow behind my ‘97 TJ. Mine will be a little longer than yours and a bit more narrow. I look forward to seeing your pictures as you go along!
 

billiebob

Well-known member
72" is wider than a TJ, the TJ body is 60" plus flares is 67" 68".....

Me too, the theme of matching vehicle width works. Stock mirrors work. Backing up is simple. But 72" will defeat that goal.
You will need trailer mirror extensions. You will not have the advantage reversing.
I have 2 trailers, both 60" wide behind a TJ, 60" works.

Devil is in the details. Where you show 45" mine is 60". Where you show 72" mine is 78".
My trailer is 60" wide, the fenders add 9" per side. As long as the 72" is blow the mirrors right on. You'll get all the advantages.
Water tank is bang on. You are the first guy I have seen to set it long ways opposed to width ways.I agree, more stable on cross slopes.

On mine all 7 rims and tires are identical.

DSCN2864.jpeg
 
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slimtwo

Adventurer
The axle I bought is the same width as the jeep. Hub face to HF is 61". with the offset of my wheels, the overall width to each tire face is just over 72". So my trailer sides will be just inside the tire face. regarding the water tank, I can get away with the positioning because of the independent suspension. I won't know the exact space I have for the tank, until I get the suspension mocked up. I'm really hoping 25 gals will fit.

Happy trails!
 

slimtwo

Adventurer
So I have officially started this trailer build. I had cut the frame pieces a few weeks ago, and today, I set it up on stands, and tack welded the first section. I am going to start fabricating the suspension arms in the next week or so hopefully.

cut frame material.jpgtack welding frame A2.jpgtacking up the frame A1.jpg

Once the frame was tack welded, I sat the axle on the frame so I can start trying to figure out where to place it.

axle placement.jpgplacing axle on frame.jpg

More later.

Happy Trails!
 

slimtwo

Adventurer
So today I placed the axle in the location on the frame that made the most sense at this point. I have been thinking about the tongue weight, and based on the placement of the items that will affect it the most i.e., batteries, water tank, fridge, firewood, and cooking gear, I think it’s close. The box area of the frame is 72 inches, making the center 36 inches. So, I set up the axle at 40 inches, behind center measuring from the front. The other factor I need to consider, is that the fridge is located in front of the axle, and there needs to be room for it and the slide out, so it has to be at least that far back anyway.

The next thing I am working on are the suspension arm lengths, and the pivot points. I decided to go 24 inches long, for the brace that runs down the frame on the outside, and 27 inches for the inside. Now before I cut them out, I set the axle on blocks to give me a static ride height to simulate under a load, and give me a rough idea for the angle of the arms (remember, I’m doing this upside down).

suspension bush.jpg

For the pivot bushing placement, I am using a threaded rod, which is running through all four inner bushings, tabs, and one washer as a spacer, and nuts on each side. This is to ensure that the pivot bushings are straight, and exactly where they need to be. Once the tabs are welded, I can remove the rod and cut the arms. There will be a cross tube inline with the frame under the pivot brace, the pivot brace will be in two pieces, to allow the tongue to pass through. Everything will be welded in place.

Continuing, I welded the frame cross brace in the frame, and I cut the bushing cross tube in half so the tongue can pass through. That way it will be integrated with the cross brace. I tacked the bushing cross brace, and tack welded the bushing tabs in place and removed the threaded rod. I then I measured and cut the outside and inside suspension arms. Before I did any more with the suspension arms, I went ahead and welded the four corners of the frame to make sure it did not move when I welded the arms in place.

bushing tabs.jpg

Next, my goal is to notch the ends of the suspension arms (2 inch for the bushings and 2 1/2 inch for the axle end. Unfortunately, I did not get pictures of that. I set up a jig on the drill press, and used a hole saw. The outside arms were a straight cut, but the inside arms had a miter cut on the ends, then the radius. The test fit showed I needed to make some adjustments, but they were pretty close.

Susp Arms 1.jpgSusp Arms 2.jpg

The biggest challenge I had, was not having enough hands. Trying to weld the arms in place, took a little creativity. Clamps and jigs are your friends when you’re alone.

Well, I ran out of steam, so I will finish welding the axle end of the arms first, then the bushing side next time.
 
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slimtwo

Adventurer
is the axle welded solid to both swing arms ??
Yes it is. This is to keep the suspension arms and axle in perfect alignment while I am welding. once I have everything welded up, I will cut out the center section of the axle, allowing it to be independent.
 

slimtwo

Adventurer
Today I welded the axle side of the suspension arms on the inside where the bracing will cover it, then I cut out the stiffeners for the suspension arms. After test fitting and cleaning everything, I clamped them in place and tack welded them.

20210623_123749 (1).jpg

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Once the bracing was tacked in place really good, I removed the clamps and took the bushings out, so I could weld the ends in place. Taking the bushings out turned out to being a major production. My tacks apparently were slightly more than just tacks. The bushings were partly welded together. So, I had to use some persuasion to get them out.
I welded the bushing ends, welded the stiffeners, and I also finished welding the bushing tabs (I was waiting to do that once the A arms were removed). Now I am ready to cut the center section of the axle out, and then, I will have my independent suspension.

I was trying not to overheat the parts, so I was welding a couple inches at a time in a spot, then rotating around. however, my start and stops aren't very good. But it is solid none the less.
20210623_143431 (1).jpg

20210623_143640 (1).jpg

Of course, now, I have to take the grinder to some of the welds that didn’t come out as well as I would have liked, but that won’t take long.



The next thing I will start working on are the airbag mounting brackets, and the shock mounts. I know there are several companies that so airbag brackets, I just haven’t found one that will work with my set up. I more than likely will have too fab my own.
 

slimtwo

Adventurer
The other thing I need to do, is cut the tongue to length and weld it on. I have been holding off doing that to keep it out of the way. But I'm at a point now, where I need it in place to finish all the welding on the frame and suspension. I'm close to being in a position to flip the trailer over and consider the ride height. It will be towable very soon.

Happy Trails!
 

slimtwo

Adventurer
More progress on the trailer today. I had to clean up some welds that I didn’t like, so I got out the grinder, and did some clean up. Once I got the touch up done, I continued with my progress.

Time to bite the bullet! Marked on the axle where I plan to make the cut… and I cut it.

0628214.jpg

I used my friend’s new plasma cutter.

0628217.jpg 0628216.jpg

The plasma cutter worked great! It’s easy to use. The problem was all on the operator. That thing cuts in fine detail. All my little movements, shakes, and tremors, were nicely transferred to the axle I was trying to cut. I had envisioned nice straight lines, and even spacing. Nope, not even close. A gator would have been thrilled to have teeth like that. Got it done though, but had some grinding to do, to even it up.

0628215.jpg

So, a big grinding job, calls for braking out the “big boy” grinder. Makes quick work of any rough spots.

0628213.jpg

Well, once all that was done, what is left, is independent suspension!!! Yah buddy!

0628211.jpg 0628212.jpg

I put the bushing back in, and reinstalled the “axles” to ensure they fit, and we’re golden.

That’s all for today. The temp crept up a little faster today, so I knocked off at noon (I’m retired, so I can leave any time I want too). Back at the shop tomorrow. I’m gonna get the tongue cut to size, and mounted, and work on the mounting for the airbags.

Happy Trails!
 

slimtwo

Adventurer
Today, I made up some caps to cover the holes where I cut the center section of the axle tube. I started off with some scrap ¼-inch plate, but that was just too thick to work with, and it doesn’t need to be bullet proof anyway. I found some 1/8-inch scrap (much easier to work with), cut them to size, and welded them in place. After cleaning the welds up, it almost looks like a professional did it.

06292101.jpg 06292102.jpg

Next, I removed the swing arms, so I could stand the frame up to weld the tops and bottoms where the frame pieces connect, and the bushing pivot supports (I don’t like welding on my back).

06292103.jpg 06292104.jpg

While I had it lite, I cleaned up the top welds where the box will eventually sit.

Back in the shop tomorrow.
 

slimtwo

Adventurer
So today I set the frame back on the stands, and reinstalled the swing arms to work on the placement and mounts for the airbags. I pondered on that for a while, because truthfully, I wasn’t sure how to proceed. So, I knew about where I wanted the ride height to be, and I knew that with 33-inch tires on the trailer, that would be about 16 ½ inches from the hub center to the top of the tire. So, I took a section of tubing and measured 12-inches up to 17-inches, in 1-inch increments, then I clamped the indexed tubing to the frame to support the swing arm at the prescribed height.

06302101.jpg 06302102.jpg

Then my friend and I took one of the airbags and compressed it as far as it would go, and measured it (2 ½-inches). Then we carefully filled it with air to get the full height of the bag (8 ½-inches +/-) at least as close as we could. We figured approximately 5 ½-inches of travel. These are firestone airbags, rated at 2500 psi each, meaning that we can mount them in front of the axles, taking advantage of the leverage, to increase their travel.

06302104.jpg

With that pretty much figured out, I moved on to fabricating the top mounting plates. I prepared myself for round two with the plasma cutter, hoping it would go better than with cutting the axle tube. This time I used a straight edge, and believe it or not, a used, worn out horse shoe, to help with the radius. And it worked.

06302103.jpg

A few holes later, and a lot of grinding, and I have the top plates ready to mount.

06302105.jpg

I went by my metal supply house and picked up some 8 x 8, and 4 x 4-inch gusset material in 3/16-inch to use for bracing the top plates, and the bottom plates. The material was there for me to use; however, it would mean that I had to cut it out and clean it up, and I decided not to do that.

Done for the day, so I will be back to work on it in a few days.



Happy Trails!
 

slimtwo

Adventurer
Today I worked on the air bag mounts. I started the top plates yesterday, and today, I worked on the bottom pates and gussets.

07012101.jpg

I spent more time pondering the angles for the airbags, and came up with the angle I figured was the right one. It looked good at any rate. For the angle, I cut a piece of 1” by 3/16” by 2” steel flat bar, and welded it on one side of the top plate.

07012102.jpg

Once I had everything ready, I measured and tacked the lower mounts in place on the swing arms. Then I took the AB, with the top mount installed on the bag, and mounted it to the bottom mounts on the swing arms. With the swing arms propped up at the determined height, the top mount rested on the frame in position, and I tacked it in place.

07012103.jpg 07012104.jpg

After checking everything again, I repeated the process on the other side. Once satisfied, I tacked the frame gussets in place on both axles, then welded everything in place.

07012105.jpg

Next time, I will look at the shock mount locations.

All for now.

Happy Trails!
 

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