The driver's side air bag on my 1986 El Camino had a leak. You can see some small rips where the air was leaking out. The big one close the the seam was the culprit. The old bag conforms to the spring after a while.
I just put the car up in the air with my scissor jack, unbolt the lower bolt of the shock, and support a few pounds of weight from the tire with my floor jack, slide the bolt out, and lower the trailing arm. The spring just wiggles out, and then wrestle and cuss at the old air bag. Squeeze it down, and cap off the nipple with a plug. Remove the old bag, and slide the new one in. It starts off life as a cylinder. It takes the shape of the spring pretty fast I bet.
Jack up the wheel to get the shock bolt to go in, torque to spec, lower the car and add in 10 PSI. The two airbags are on separate lines, so I can load level as needed. I run with 8 to 10 PSI in them most of the timebut I can go to 20 PIS if I need to raise the rear end for a load.
I am the worlds slowest mechanic, and the airbag replacement only took me 40 minutes from going the the garage to coming in mission accomplished.