So today I was at my work picking up a pickle bucket to wash my truck, and me my manager, and a co worker were standing around my 2000 ZR2 Blazer talking and my manager randomly opens the gas cap cover and notices a little air valve looking thing coming through the inside metal plate surrounding the gas cap itself. It looks like the air valve in which you would inflate your tires, but i have never noticed it before today. my co worker said it may be for air shocks or something like that. i just bought this truck a few months ago from a high school kid who did not know much about it when he sold it. i just wanted to see if i could find out exactly what it was before i go messing with it. thanks in advance for any help

 

Go to the back side and see where it leads to!

 

More than likely a previous owner install air shocks. Pretty easy to find out by just looking at the rear shock and see if they do indeed have an air line. Air shocks can be great and also a PITA. If you do have air shocks, I'd recommend carrying a portable compressor to add air when needed.

I had an old Camaro that had them. Loved them as I could adjust as needed but I didn't have a compressor. When you have a load, you add air. When you don't have a load, let some air out. Worked great except when I added two bodies to the back seats and then had to go to a filling station to add air.

 

Shocks

 

Thanks everyone! It is indeed air shocks thats neat to have! I fond something new every day about this truck!