About 34 years ago when money was tight raising a family, I wanted a trailer to tow an old VW dune buggy to the desert. A friend gave me a pair of VW bus front spindles, hubs with drums and an old VW bug rear torsion member. I use a piece of 2” square ¼ wall tubing between the two hubs. I just clamped the tube in a vice and leveled it with a carpenter’s level. I, drilled holes to line up with the lower hole in the hub and used a big bolt to put the two together. Because the axle was level in the vice, I use the lever to level the rim vertical to the tube (after adjusting for rim run out), and measured and adjusted the tow in. When everything was perfect, I started the old buzz box welder and glued the spindle to the tube. I then cut gussets and welded them upright along the sides of the hub. I widened the torsion tube to line up with the gussets that I had drilled to match the torsion plates and put a piece of tubing between the torsion member to make it wide enough for the axle. I made new mount plates for the ends of the torsion member and bolted the torsion member to the sides of a couple of landing mats that were scrapped from the local military field. I welded a ¼ by 5 inch piece of metal to the landing mat on the outside edge. I used a section of Pontiac frame rail across the landing mat to form the front cross member and a piece of 3 inch pipe as a tongue with a gusset on each side and on top. I used another 3 inch pipe for the rear cross member. I used a piece of pipe from the axle on one side to the trailer on the other side as a sway bar. Never got around to put shocks on it and was always going to put a surge brake setup on it, just never got around to doing it. It worked great to haul the buggy.
As time went on, I built a second axle and torsion member to make it a tandem trailer. It is now over 34 years old, has a million miles on it, and has been from Canada to the tip of Baja, from San Diego to New York more than once. I have hauled buggies, garden tractors, pickups, my minivan, corvette, my CJ5 Jeep, building materials (sand, rock, cement) and on one occasion, crossed the scale at the dump with over 6000 pounds of tree stumps. (See attachment). The trailer is in my back yard now with over 4800 hundred pounds of vinyl fencing on it.
This might not be the most heavy duty trailer and I don’t recommend overloading one like it for long trips. I drive very cautiously when it is overloaded but have never felt it to be dangerous in any way unless it was the stopping power with a heavy overload. It is totally quiet behind the tow vehicle, and normally, you can not feel it behind you. In fact, I make a wide light bar so I could see it behind my motorhome so I would know “where it was”.
I have built several using the front spindles from cars/trucks to match the tow vehicle for friends. I bolt the spindle to the square tube to line up the camber and toe in and use it up side down for a lot of axle drop or right side up for a high clearance trailer. It works great for me and the torsion suspension setup works great. I built one three axle trailer using the VW bus rear torsion tube for some guys that had an off road race truck along with the 1 ton front truck spindles and a surge brake system.. They love it.
Sorry for the long post, but though it might be interesting.