School me on airbag systems

[Proxy]

Yesterday, I test drove a used truck (2007 1/2 ton GMC Z71 4x4) and noticed that it was very harsh on bumps. My naivety led me to believe it was just a crappy suspension.

Well, fast forward about 20 minutes when I'm leaving the dealer and I noticed it has a rear airbag system for towing. My guess is the dealer has no idea it is there.

I'm kind of indifferent on whether this is good or bad since the truck only has 51k on it, but I would like to figure out how to let the air out so I can do that if I go back to the dealer.

Are all of these systems automatic with a switch to a compressor somewhere or could there be a Schrader valve hiding somewhere to let the air out of the bags?

[gasjob2500hd]

they make both being i dont belive chevy ever had made any pickups with air ride? correct me if im wrong

everyone i know has aftermarket bags i know people with both on board compressors so they can adjust at the flick of a switch and i know friends with the schrader valves sticking out the back where they have to manually make adjustments

it depends on the kit i myself want to get air bags but im going to have to customize the mounts cause i have blocks the on board air is nice but alot more money

[Proxy]

Originally Posted by gasjob2500hd

...and i know friends with the schrader valves sticking out the back where they have to manually make adjustments

Aha! I'm glad you mentioned that. I noticed a few things sticking out the back of the truck, right next to the wire harness adapter. I bet that's what those were.

I was about to ask the sales lady what they were and she starting talking about something else and I forgot to ask.

[gasjob2500hd]

the coolest thing ive seen is a few people stick them out where the bolts go to hold on ur license plate and screw small nuts on the shcraders to hold on the plate i think thats pretty cool

[Proxy]

Originally Posted by gasjob2500hd

the coolest thing ive seen is a few people stick them out where the bolts go to hold on ur license plate and screw small nuts on the shcraders to hold on the plate i think thats pretty cool

Now that's slick.

I can see it now... someone passing by saying to themselves "I wonder why he's airing up his license plate?"

[Proxy]

BTW, is there any chance that having the bags at too low a PSI would cause a rough ride while towing nothing? I had the dealership check out the bags and they said they were UNDER-inflated, causing the rough ride. That doesn't make sense to me.

[bored&stroked]

These are helper springs right? If so then being under inflated would just mean you'd be riding on the stock leafs without help.

[gasjob2500hd]

x2

[sledgarage]

I have airbags in my 08. When I'm not hauling anything I keep the bags around 5-10 psi and the truck rides fine. I have also have the compressor and IMO, that's the only way to go. I can adjust the pressure from inside the truck as I drive.

[sledgarage]

Originally Posted by Proxy

BTW, is there any chance that having the bags at too low a PSI would cause a rough ride while towing nothing? I had the dealership check out the bags and they said they were UNDER-inflated, causing the rough ride. That doesn't make sense to me.

Your dealer is an idiot. If the airbags don't have any pressure in them you're just riding on the stock leaf springs.

[leveldowen]

Are we sure we're talking about air springs and not air-adjustable shocks? If they are in fact airbags (springs), the factory leaf packs may have been modified for some reason, requiring air in the bags to ride properly. Or the springs are just so worn from being overloaded that they ride on the factory overloads if the airsprings aren't inflated.

[Proxy]

This is exactly what the truck has: http://www.fsip.com/riderite/

Fortunately, the previous owner left the instruction booklet in the glove box. The dealership was indeed wrong. Without any weight in/on the truck, bags should be around 5 psi. At that pressure, it rides perfect.