I'll acknowledge that this subject has been beaten to death, but all of the replies have to do with squeezing the new bags through the little hole in the bottom of the control arm. Has anyone simply removed the coil springs? I have done this on several cars - disconnect the lower balljoint and lower the control arm with a jack until there is no more tension on the spring. There is the possibility that the spring will fly out and remove your head from your shoulders, but so long as you stand clear it can be done. I've never had a spring fly out. Reinstallation is pretty much the same - you wedge the spring back in the pocket with a crowbar and jack the lower control arm up using the weight of the car (or RV) to compress it. Put the nut back on the lower ball joint and you're good to go.It seems to me that this is less time consuming, and less frustrating. Or am I missing something? Can you not safely remove the coil spring in the manner I described?

Brian in Michigan wrote:Something like thisI installed new henderson springs just like in the video. They don't come flying out at you. If your going to do all that work I would throw the bags and springs out and get the proper springs for the weight of the front end.

Brian in Michigan wrote:Something like thisYes! Exactly like that. Seems to be a lot less hassle than trying to squeeze a big bag through a little hole.With regard to springs versus bags, I've read conflicting opinions on it. Some say the original design (springs and bags) provides a better ride over stiffer springs. Dunno.

That's why you order the right springs.Ours rides great with super steer springs fromHendersons.

Doing it your way you should at least use coil spring compressors!How ever anyone does it make sure that you smooth down the sharp edge where the hole was punched in the A-Frame.I have used a die grinder with a stone wheel but a Dremel or even a drill with a stone wheel will work.

Front Air Bag Replacement - Chevy P30 Chassis | Good Sam Community

34 Replies

turbojimmy
Explorer
Jun 26, 2014
Welll...I didn't get a chance to put the bags in. Going on a 250-mile (round trip) trek this weekend so hopefully it won't shred the tires.

I had the propane tank filled (80 lbs.). It's mounted pretty much mid-way between the front and rear wheels on the left side. That brought the left control arm almost down to the snubber. It's no wonder, though - the weight is not distributed well on this thing at all. The generator, freshwater, black water and propane tanks are all mounted on the left side. There's hardly any weight on the right side (relatively speaking).

I may go the new spring route instead....
turbojimmy
Explorer
Jun 18, 2014
mike brez wrote:
Lots of info Here Page 18/19 I believe has the bump stop measurements

Yes! That's an awesome document. I printed it out when I found it a few weeks ago. Trouble is, the axle ratings start at 4,300 lbs. Mine says 3,900. I guess I can use the 4,300 specs.

EDIT: And according to the chart, I should have 2.5" clearance with the bags properly inflated. Would the bags give me an extra 1.5" at 50 PSI (the max recommended for a 4,300 lb axle)? Not likely.

I'm going to pop them in anyway. It can't hurt. And they are a b***h to fold in half. I left them in the sun for a bit to soften them up and, as people have said, it can be done.
mike_brez
Explorer
Jun 18, 2014
Lots of info Here Page 18/19 I believe has the bump stop measurements
turbojimmy
Explorer
Jun 18, 2014
Gjac wrote:
What is the weight rating on yours?

According to the sticker in the cab, the GAWR for the front axle is 3,900 lbs.

I'll probably get to it either Friday or over the weekend. I'm going on a 200-mile round-trip excursion at the end of the month so I'm feverishly buttoning up all the small stuff. I've never had it more than 10 miles from home since I got it running (I bought it with a bad engine).
Gjac
Explorer III
Jun 18, 2014
Jim I replace a leaking bag 10 years ago and I can't remember the specifics (I'm old). Depending on the weight of your chassis the ride height dimension is different for my 5500 lb front I needed between 1 1/2 -1 3/4 ins. What is the weight rating on yours? I would drive to a flat area and measure. If that is too difficult just reverse you MH in the driveway and see if the low dimension shifts to the other side. If I remember correctly fully inflated bags added about 1/2 in of ride height on mine, if you follow the procedure that I described in my previous post just air up the bags without using the jacks added about half that. The bags gave about 500 lbs more capacity each to the front end.Keep in mind any HD spring would replace the bag spring combo. Stengler Bros was cheaper. The puck as you call it on the bottom I believe is part of the bag and will come out.
turbojimmy
Explorer
Jun 18, 2014
Gjac wrote:
Jim, Then you are good. What does the clearance measure? What is your front axle spec weight? If you have at least an inch, inch and a half clearance, when you inflate the bags you will pick up even more. If you raise the jacks then inflate the bags and then lower the jacks, this will give you more ride height over just inflating the bags with the weight on them. The new bags are easy to install as I remember, I sucked all the air out lubed the bag and installed it through the jacked up coil spring opening. I would inflate it to the lowest inflation that will give you about 1 3/4 ins. I say this because the springs will get weak over time and the ride height will diminish affecting the front end alignment. As they get weaker you can always raise the ride height by adding pressure keeping the same ride height.

I took a couple of pics real quick. I couldn't find my tape measure, but it looks like I have a bit under an inch on the right and about half that on the left. The driveway does have a pitch to it, so that might have something to do with it.

Right side:

Left side:

They're a little blurry, but I hope you get the idea. Not sure which axle I have, but the GAWR tag says 3900 for the front.

This is the hole I have to work with:

I was confused by the puck in the bottom. Looks like that will come out?
dougrainer
Nomad
Jun 18, 2014
turbojimmy wrote:
Gjac wrote:
dougrainer wrote:
P-30 chassis with the front air bags in the coil springs. THIS IS NOT A RIDE HEIGHT BAG. IT IS A BAG REQUIRED FOR THE WEIGHT OF THE CHASSIS FRONT SUSPENSION. THE BAGS ARE REQUIRED TO BE INSTALLED AND AIRED TO AT LEAST 75 PSI TO GET THE FRONT END TO THE SPEC WEIGHT RATING and alignment and driveability. . Now, if the aftermarket Henderson kits address the increasing of the front end weight rating, then install that type kit. Doug
Doug if the A arm is resting on the stops with the bags fully inflated it will make for a rough ride. Mine had 1/4 in clearance and my friends P30 was resting on the stops at 90 psi, both were fixed with the Henderson SS. You need clearance for the spring to compress to absorb the bumps.

I know you were talking to Doug, but this is good to know. With no air in the bags I have plenty of clearance to the stoppers.

Chevy used the air bags to INCREASE the weight rating of the front end of the P-30 chassis and the Bags are required to be inflated to get that rating. Nothing else. You can adjust the pressure, but if I remember, 75 was the minimum. Doug
Gjac
Explorer III
Jun 17, 2014
turbojimmy wrote:
Gjac wrote:
dougrainer wrote:
P-30 chassis with the front air bags in the coil springs. THIS IS NOT A RIDE HEIGHT BAG. IT IS A BAG REQUIRED FOR THE WEIGHT OF THE CHASSIS FRONT SUSPENSION. THE BAGS ARE REQUIRED TO BE INSTALLED AND AIRED TO AT LEAST 75 PSI TO GET THE FRONT END TO THE SPEC WEIGHT RATING and alignment and driveability. . Now, if the aftermarket Henderson kits address the increasing of the front end weight rating, then install that type kit. Doug
Doug if the A arm is resting on the stops with the bags fully inflated it will make for a rough ride. Mine had 1/4 in clearance and my friends P30 was resting on the stops at 90 psi, both were fixed with the Henderson SS. You need clearance for the spring to compress to absorb the bumps.

I know you were talking to Doug, but this is good to know. With no air in the bags I have plenty of clearance to the stoppers.
Jim, Then you are good. What does the clearance measure? What is your front axle spec weight? If you have at least an inch, inch and a half clearance, when you inflate the bags you will pick up even more. If you raise the jacks then inflate the bags and then lower the jacks, this will give you more ride height over just inflating the bags with the weight on them. The new bags are easy to install as I remember, I sucked all the air out lubed the bag and installed it through the jacked up coil spring opening. I would inflate it to the lowest inflation that will give you about 1 3/4 ins. I say this because the springs will get weak over time and the ride height will diminish affecting the front end alignment. As they get weaker you can always raise the ride height by adding pressure keeping the same ride height.
turbojimmy
Explorer
Jun 17, 2014
Gjac wrote:
dougrainer wrote:
P-30 chassis with the front air bags in the coil springs. THIS IS NOT A RIDE HEIGHT BAG. IT IS A BAG REQUIRED FOR THE WEIGHT OF THE CHASSIS FRONT SUSPENSION. THE BAGS ARE REQUIRED TO BE INSTALLED AND AIRED TO AT LEAST 75 PSI TO GET THE FRONT END TO THE SPEC WEIGHT RATING and alignment and driveability. . Now, if the aftermarket Henderson kits address the increasing of the front end weight rating, then install that type kit. Doug
Doug if the A arm is resting on the stops with the bags fully inflated it will make for a rough ride. Mine had 1/4 in clearance and my friends P30 was resting on the stops at 90 psi, both were fixed with the Henderson SS. You need clearance for the spring to compress to absorb the bumps.

I know you were talking to Doug, but this is good to know. With no air in the bags I have plenty of clearance to the stoppers.
Gjac
Explorer III
Jun 17, 2014
dougrainer wrote:
P-30 chassis with the front air bags in the coil springs. THIS IS NOT A RIDE HEIGHT BAG. IT IS A BAG REQUIRED FOR THE WEIGHT OF THE CHASSIS FRONT SUSPENSION. THE BAGS ARE REQUIRED TO BE INSTALLED AND AIRED TO AT LEAST 75 PSI TO GET THE FRONT END TO THE SPEC WEIGHT RATING and alignment and driveability. . Now, if the aftermarket Henderson kits address the increasing of the front end weight rating, then install that type kit. Doug
Doug if the A arm is resting on the stops with the bags fully inflated it will make for a rough ride. Mine had 1/4 in clearance and my friends P30 was resting on the stops at 90 psi, both were fixed with the Henderson SS. You need clearance for the spring to compress to absorb the bumps.