I am hashing out the suspension for the rear of my 28 RPU. The design so far has been based on parts I already own. The chassis is a home built with 2x3 box tubes. I don't want to build it dangerous though. Unfortunately I don't have a picture yet for this post so hopefully I can explain it clearly.

Picture this. 9" rear. I built a couple of suspension arms. The rear section which I will call my spring perch is a piece of 1" x 4" C channel steel about 10" long. I will cut out a half moon on each side of the 1" sides and this will ride on the top of the axle tube and welded in place.

The arms are some pretty thick 2" pipe. The pipe is welded to the spring perch. I split the pipe and flattened each side so that I could slide it onto the horizontal surface of the perch and weld it to each side.

The arms are about 36" long. I plan to weld in a bung and install Heim joints which will then be bolted through a crush sleeve through the frame. The arms will be very nearly parallel with the frame. Very typical from what I've seen.

My concerns...am I allowing enough flexibility in the suspension? Am I making the arms too rigid? Just trying to picture how the suspension will travel. Up and down are fine, but what about when the rear end twists side to side?I haven't welded these arms to the axle tubes yet.

I'll try to post/draw some pictures.

It won't. If you want it to you will need to look into a different type of suspension.