This may be an awesome idea, or the craziest/dumbest thing you ever heard... Here goes.

I'm wanting to design an air suspension for the rear based on that of a semi. I'll add some pictures in a bit.

What i'm wanting to do is use 2"x3"x1/4" wall tubing to come back from the front hanger and drop behind the axle, leaving room for the air bag. One side will also have a mount for the panhard bar.

The leveling valve will mount wherever is convenient. The air will be provided by my York compressor.

What do you all think of this? Where are the weak points, and what is overkill? Help me fine tune this please! (If it is feasible in the first place...)

 

This shape of beam:

^This suspention setup is rated for 20k an axle...
So is this \/
But the bag mounted like this:

 

2 link basically. its the same setup they have on the newer tahoe's except they use 4 links total. the biggest issue with that, is as the air bag goes up and down, it changes your pinion angle radically. thats why 4 links are used now. they used setups like that on pre 71 chevy pickups. coil over though. why not just build a 4 link? thats next on my list.

 

I'm not sure i'm capable of building a 4 link... I was thinking if this system has worked for semis for millions of miles, it would work for me. And actually, the distance between the axle and the front hanger would be greater on my truck, so i think the angle would change less.

 

I'm going with a similar system on my F250, basically I am going to replicate the Chevy system with a few alterations- I am going to run arms forward to just behind the center support bearing, about 18" apart at that point, and back to the original perches in the rear, with airbags behind the axle. The panhard rod is the easy part, a pair of heim joints and a piece of tube. Make it close to the length you think you'll need, and then adjust it to be right at the proper ride height.
As far as airbags and the leveling valve, you can get that stuff at any truck dealership or online. Most dealerships have a Firestone catalog so you can select the exact airbags you need for your application. The leveling valves aren't cheap, but not too expensive either, $60-$100 typically.
You will need a swaybar as well, especially if you are towing.
Make sure you gusset the welds on the mounting tubes, there will be a lot of stress there and it would kind of suck to have it fail.

 

Just remeber to bolt all the hardware to the frame, no welding. The steel has been treated and welding on it will change the hardness etc. Ever notice how the frames are rivoted not welded. This is due to the fact that rivots or bolts will handle the constant flew of the truck welding will not.

 

Check out this website:

Road Tamer Air Suspension System by Air Lift

they make kits like what you're wanting, just not for our years, gives you some good ideas though if you wanted to make it, looks pretty straight forward.

 

Yep, I planned on making little triangle gussets. We have leveling valves laying around at work. I didn't think about the sway bar... I'll have to find something...
Another little trick i was going to add was a dump valve to make loading the bed easier.


Planned on it. But thanks for mentioning it. I can't weld cast iron, but would it be ok to weld on the steel axle tubes? I don't think i'll need to, but just in case...

(The dumba** previous owner welded the rear bumper and a hitch to the frame. I'm going to have to grind it back down. I'm also going to make a custom hitch to bolt on the rear)
I've heard of that before. Expensive as anything... Even if they did offer them for our years, i want to build this.

 

Welding to the axle tubes would be fine. Just remember they are thicker than the metal you will be welding to them and you wil want to preheat them a little so you get good penetration and not over heat the thinner material.

 

That really depends what i'm welding to it...

Question: Is 1/4 plate good for hangers and mounts? Overkill? Underkill?

 

that should be good. Most of the lift kits etc. out there all brag on useing 3/16" for their hardware lol. Just make sure to gusset every thing to prevent side loading.

 

you need to join PSN just for this project
The user me2 has done extensive research and testing on this.
Problem with air ride suspension... sort of... long - Powerstroke Nation this is the link to his thread there.
Good luck! have fun BE SAFE IN YOUR TESTING.

 

Thanks djanzen!

 

also just a reminder even tho the axle tubes are thick, try not to lay full beads and get the tube too hot because even the smallest warp will over time, ruin the axle

 

Been reading that thread that djanzen posted, and i think i'm going to try and mimic me2's rear suspension. I just need to do a lot of reading about 4 links....