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Firestone Helper Airbags- 1991 Chevy Suburban (air springs)

Discussion in 'Towing & Trailer Tech' started by Crawdaddy, Jul 7, 2012.

  1. Crawdaddy

    Crawdaddy Moderator Staff Member Platinum Contributor 1000 Posts

    I just finished installing a pair of Firestone helper airbags on my 91 Chevy Suburban tow rig/road trip truck. These airbags, or air springs as Firestone calls them, are designed to help level the truck under load. They make many kits that fit most trucks and SUVs. The kit that fits 73-91 Suburban 1500 and 2500 trucks which includes me is kit #2100. Firestone claims that they do not increase the maximum capacity of the truck, and legally, they don't. But, I am using them on my truck to help offset the lower weight capacity of my 1/2-ton springs; my axle is more than up to the task of the additional load since it is a 1-ton 14-bolt axle with 4.10 gears.

    For my particular application, I had to drill 3 bolts holes in the frame rail for the upper bracket and enlarge an existing hole. I first enlarged the existing hole, then used a large C-clamp to hold it while I leveled the bracket and drilled the other 3:
    IMG_0363.jpg

    Then I pulled the upper bracket off the frame rail and assembled the upper bracket, air bag, lower bracket, and air fitting. After assembling the setup, I bolted it back to the upper frame rail and using the carriage bolts and lower bracket brace, secured the lower bracket to the spring pack. I had to shift the bracket slightly to make sure the bag was vertical.
    IMG_0364.jpg IMG_0365.jpg

    Then I hooked up the airline to the bag, and routed it to the air chuck fitting. I placed the air chuck fitting in an existing hole in the body that was slightly behind the tire, but still accessible with the tire on:
    IMG_0387.jpg

    Then, it was time to air the bags up. I aired them up in steps to illustrate the lift generated by the bags. First, with no air:
    IMG_0372.jpg

    Then I stepped it up to 25 psi:
    IMG_0373.jpg

    Then upped it to 75:
    IMG_0375.jpg

    With no real weight, the bags were ballooned out pretty good:
    IMG_0377.jpg

    With the bags aired up to 75psi, we took it out for a quick test drive. The ride really wasn't rough like I was expecting it to be, but it was obvious the suspension was stiff because the rearend felt like it was skipping and not keeping good contact with the road.

    Here's what it looked like sitting on the tires with 75 psi. The rear's pretty darn high with all that air in the bags:
    IMG_0378.jpg

    And here's what it looked like with around 10 psi; much more reasonable:
    IMG_0380.jpg

    Since I just got them installed, I haven't done a load test with them. I may hook the camper up to see what it looks like with the bags installed and inflated. I should be able to level out the rear quite nicely with them. I'll update the thread once I get some driving time in with the bags both loaded and unloaded.

    Questions, comments, and otherwise are always welcomed.
    Last edited: Sep 9, 2012
  2. Grizzly Guy

    Grizzly Guy New Member

    done the same airbag setup on a 1993 Chev 1/2T 4x4 I had,worked very well ,but never ever did I put 75 PSI in,even to see what it would look like,nice job by the way.
  3. Coach24

    Coach24 New Member 1000 Posts

    My company vehicle is a 2002 E450 wih a 30' motorhome box on it. With the Firesone bags I try to run 80 PSI and it helps with the leveling and stops the huge amount of sway when they are deflated. Sadly mine leak and the company doesn't want to repair them , because other trucks don't have them and they do just fine. ???? Other truck have different suspensions as most are F550 chassis.

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