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So spring is just around the corner and I'm itching to get Truck Norris out of the garage. That means finishing the 7004 swap and fuel injection. But one of the goals for the truck is to be able to tow my CJ around the flatlands. Having 1/2 ton springs, I know that it's going to sag a bunch in the back when I get the trailer loaded up and a bed full of camping gear and assorted parts. I want to add air bags to supplement the leaf springs. I know modern trucks have kits available to bolt in but good luck finding anything for a J10 running J20 axles and a lift kit. So I'm going to have to make my own kit.
As far as complexity, I know I can just put bags in with a fill valve all the way to a fully automated self leveling system. I want to end up somewhere in the middle. I'll be setting it up so I have on board air available and I bet I could find a decent control panel to run from the cab so I can manually add and remove air pressure when I want. But does anyone have any experience with the air bags themselves? Would it be better to mount the bags outboard on top of the springs and have a bracket bolted or welded to the frame? What about between the frame and the axle? Or even in board?
Anyone ever done this who can offer useful advice?
I am real close to doing this with my 89 Waggy. Close as in - the stuff is sitting in the garage. I bought the AIR LIFT 59507 Ride Control Rear Air Spring Kit. BJs has this one. I also bought the Air Lift 25852 Load Controller Dual Standard Duty Compressor to control them. I liked the fact that you could inflate each bag separately to help with drivers side lean. I believe these will mount outward on the frame. I think there was a pretty cool post on install in another full size jeep website that I won't mention here . I think it was in the tech archives which are still accessible (for now). Looking forward to see what you come up with.
derf wrote:I've seen that kit but I'm not sure how well it will work on a lifted J10. Maybe I can invert the top bracket and have it closer to being a bolt in.
Yeah - maybe you can. I kinda figured out half way through typing that your's was a truck and lifted. I kinda just went with it.
I'm running the AirLift kit on my 89 waggy. I like it and recommend it. Pretty basic install. Directions were good. The bags mount outboard the frame , on top of the springs. Its alittle close to the tire but it doesn't rub. If your truck is a wide track then you should have even more clearance. I think flipping the frame bracket would be work just fine due to your lift.
J-10s and 20s don't have much in the way of outboard space. Waggies and Cherokees have several inches of space, but the truck only have one or two inches, at the most.
derf wrote:Yep. The rear frame is quite a bit wider on the truck than it is on the wag. And I have oversize tires so that may squeeze the space even more.
But what about mounting the air springs in board of the frame? I could easily weld a spring perch on to the axle for the air bag to sit on...
I think I saw a kit on their site that did just that...
What about directly under the frame? Everything would probably end up shifted toward the inner side due to the spring perches but this would give you the most similar geometry to the leaves as possible. J-trucks tow so well due to just how far outside the frame the springs are, this gives them a lot of leverage between the frame and axle.
I've considered air bags for a long time, I would be very interested pics and continuing thread.
aa
1983 J-10 - 4.6L(MPFI)/CS130D/Hydroboost/NV3550/D300/44/44/3.54/Disc-Disc/32s/42 gallon 'burb tank
Cecil14 wrote:What about directly under the frame? Everything would probably end up shifted toward the inner side due to the spring perches but this would give you the most similar geometry to the leaves as possible. J-trucks tow so well due to just how far outside the frame the springs are, this gives them a lot of leverage between the frame and axle.
I've considered air bags for a long time, I would be very interested pics and continuing thread.
aa
Without having measured anything, my gut reaction is that there won't be enough room between the frame and the axle. Not only do you have to have room for the compressed air bag but also room for the air fitting at the top of the bag. And all of this has to fit at full compression. My gut tells me that I won't have enough room unless I run the air fitting through a hole in the frame...
Now wait a minute... Running the air line into the frame...
Yah I was just thinking the same thing...the fitting will have to go through a hole in the top of the bracket anyway. And if you're already lifted you should have a bit more room than stock. Not sure how much that works out to, but if you can do it straight to the axle tube instead of the spring perch that will be even a little more room. How tall are the bags compressed?
aa
1983 J-10 - 4.6L(MPFI)/CS130D/Hydroboost/NV3550/D300/44/44/3.54/Disc-Disc/32s/42 gallon 'burb tank
The minimum compressed height is 2.2" and the maximum extension is 10.5". I read that the other day and I was thinking it was taller than that. I'm going to have to get under the truck and do some measuring this weekend.
There are thousands of different airbags available. Also if you have to modify a kit it might be easier just to get some universal brackets and set it up that way.
I think the automatic valve would be a great addition to the system. They're pretty simple devices. The valve bolts to the frame and a pushrod connects it to the axle housing. It would make the system completely hands-off. Unloaded, the bag would be empty and the ride would be normal. Loaded, the bag would fill and the ride would be normal. Even brand new the valves aren't expensive. But if budget is a concern you could always find one at a big rig salvage yard.
I think the valve also serves as the dump valve for the suspension. Throw a switch and the valve ignores the pushrod position and vents the bag to the atmosphere. That could be handy when flex was important.
I'm sure the valve is designed for that. I don't think it dumps all the way to the bump stops. But the dump feature is an option anyhow. I'd still run the valve if I was planning to use airbags. Just because it's a lot cheaper and easier than the fancy systems and more consistent than manually inflating/deflating.
It occurs to me that the bump stop for the rear axle is on the bottom of the frame. If I put my air bag between the axle and the frame there won't be a bump stop and that can be "bad". With the lift I probably need to extend the bump stop a bit anyway.
I think I'm going to end up with the extended bump stops and I'll put the air bags in board of the frame.
I don't remember if the frame is fully boxed back there. If not, it's a good excuse to box the frame to add some strength to a point that wasn't intended to hold extra weight and then weld the upper bracket to the plate I weld in to box the frame.
I talked to Air-lift abut this possibility. They gave me what measurements they would need to try to match a kit up to my frame / axle / height. There were a number of measurements but they were quite helpful.