Air bag rear suspension

[Herman_Bolger]

We have a '93 dually 4x4. we just installed an ss diesel 4" exhaust, slipped right in, job went great. Now we are looking at removing the stiff rear springs and replaceing them with an air suspension. Has anybody done this? We are removing the the springs completely, not just adding supplement bags. Any advice comments?

[Barry Nave]

I went with www.truckspring.com (http://www.truckspring.com)
You can also do an internet search and fine may others
I went with the Firestone Air Spring on my C3500.Being a work truck with heavy tool loads that stay on the truck,only the front over load leaf was touching and the rear leaf was 1/2" from hitting the stop. Any little bump on the road would hammer the rear leaf. The airbag brought the truck up and off of the over load stops. Truck ride is like riding on air.
Also I can change PSI in the bags for different loads keeping truck level and steering stright with out the front being light.

[Cowracer]

Air Ride suspensions makes a "Air-over-Leaf" setup. It retains the top leaf of the spring to locate the rear axle and then airbags to support the weight. That is the cheap setup.

The High $$$ setup is the AirBar. It uses a 4-link with panhard bar that completely replaces the stock springs. It is bolt in, but costs around $1800

Tim

[Herman_Bolger]

Thanks, We have been looking on the net for heavy duty rear air kits and found most of them are an overload type system. The truck spring site has the system that we would like, the "primary air" type. But cannot justify that much money. I think we will be building our own set up.I am sure that we can fab our own trailing arms, and go to the truck parts store and find a proper size air spring. That was the other thing i noticed most of the "kits" only use 2500 lb air springs. Our trailer has a pin wieght of about 3000 lbs plus it still has to hold up the rest of the truck. Thanks again, if anyones interested i'll keep you posted.

Herman

[a5150nut]

Herman

I remember seeing a setup in Trailer LIfe Mag. they used 2x3 or 2x4 tubing in place of the rear leaf spring. They located the air bags just behind the axel. Used front spring mount for front mount of tubing. Traction bar looking setup. Also used a Panhard bar to locate axel in frame. IIRC they mounted hard to axel houseing. If I were to do this I think I would have some sort of longitudal pivot at axel conection to allow for twisting without stressins axel housing.

[Herman_Bolger]

5150,

That's what i was thinking, 3x2x 1/4" tubing,press a new leaf spring bushing into the front of the new trailing arm, panhard bar etc. I'm sure we can figure this out.

[JoeyD]

I would just remove the rea spring hangers and start with clean frame rails. i would beef the frame up by boxing it and then just fab up a 5 link system.
Very possible to just use a sytem like Ford uses on the front of the 05 Superdutys with 1 arm to locate the axle on each side and then a track bar. Big rigs use a similar set up.

[a5150nut]

Herman,

I was looking for something else and ran accros this site AirLift Suspension (http://www.airliftcompany.com/PrimaryAirWeb/index.htm) . This is what I had seen in the Trailer Life Mag. I had talked to one of their engineers asking how this worked off road. He said it was designed for highway use only. But the picture is good for ideas.......... :eek:

[Herman_Bolger]

We did see the air lift site and we are planning on making a very similar set up. They have the bags behind the axle, we are looking at mounting ours on top. There is a small pad there already that we are going to enlarge then make an uppper pad at the frame and intall the bag in between. This should keep everything nice and neat and less chance of later damage. The truck is under reconstruction right now but we are quite busy in the shop right now so things are moving a little slow. I will let you know when i post some pics up on our site, if your interested. Spring is only 6 weeks away have to get this done soon.

[Herman_Bolger]

Well it's been a couple of weeks, we made the trailing arms out of 4x2x3/16 box tubing,welded a heavy tube at the front to fit the factory rubber bushing, so we could use the factory front mount. Ended up puting the firestone air spring behind the axel, like the other guys kits, why reinvent the wheel? Used a air spring from an air ride trailer has about 6500lb capacity, each. Had to remove the tail pipe for now, was to close to air spring, will modify and put back on. just working on the panhard bar now. Should be "rolling" shortly. Since we are going through all this, We lowered the frt torsion bar 1" and dropped the rear about 3.5" should have a level look when its back together. I will try to get a link to some pics,soon. still have to paint the whole truck yet also. To many projects, not enough time. Speaking of which, look for my new thread, put a 6.5td into a boat. not enough time, whats one more project.

[96ccdd]

I know you are working on it,but you may want to check this out http://www.keldermanmfg.com/category.php?id=23

[Herman_Bolger]

Mark, checked out that site, nice stuff. their pricing is pretty good also. Well its to late for ours now were already into it to far to change now. It did give a good idea about side to side load level control, thats nice.I will post a link when i can to our set up.I dont like to pay for stuff anyway, why take the easy way, even though sometimes it's cheaper and leave more skin on the knuckles, were's the fun in that!!!
Herman