Air bag anatomy picture

[Ivan K]

So, out of curiosity I dissected an airbag that got a tiny pinhole in its middle section, not where I would have expected it. The inside is looking pretty good still, being original since 2000 and approaching 200K. It gave me some more confidence, eventhough I have a spare and equipment on board to replace one anywhere. It's almost 1/4 inch thick, pretty solid and tough to cut. One day I may get proactive but not today.

[JDCrow]

Awesome! Thanks for insight. How’s your Sig coming along? 

[Cubflyer]

Nice work Ivan!

I have been wondering what was inside one of those "bags".... especially like seeing that there is an internal "stop" that 'limits' the total collapse.....

Wonder if injecting "Slime" into one with a pin hole would seal it up...??

Ken

[Trinidaddave]

Have you posted the process used to replace your air bags? Did you follow someones procedure.

I would like to do the work, but want to make sure I do not miss a step.

[Ivan K]

10 hours ago, JDCrow said:

Awesome! Thanks for insight. How’s your Sig coming along? 

Thanks for asking, JD. The Sig is doing pretty great. Just the usual maintenance and wear repairs such as this one.

 

1 hour ago, Cubflyer said:

Nice work Ivan!

I have been wondering what was inside one of those "bags".... especially like seeing that there is an internal "stop" that 'limits' the total collapse.....

Wonder if injecting "Slime" into one with a pin hole would seal it up...??

Ken

Ken, it crossed my mind too, as a lazy fix and knowing how well it works for the lawn moving equipment but how to teach the slime to climb inside walls without removing the bag. Once removed, you have pretty much won the battle. This one was a bear to reach, being between the front tire and stairwell. The drive axle fronts won't be any better but really not that bad with the right tools. I think a tire plug would have worked well in my respective case if in a pinch.

[Ivan K]

3 hours ago, Trinidaddave said:

Have you posted the process used to replace your air bags? Did you follow someones procedure.

I would like to do the work, but want to make sure I do not miss a step.

David, I learned from a number of posts over the years (recently from Jacwjames) and while every coach is different, the principle remains the same. Unless you have flip-up fenders, access to some bags is a bear. I can only talk to my coach, with air leveling. I aired the suspension way up to place 4x4 at a good spot between the h-frame and frame rails in all 4 corners. There are much better ways than a 4x4 but it works for me. Then I deflated bags on that axle. There still will be some minor pressure because that's how HWH works but that's not a problem. That part would be different with hydraulic jacks. We only have 4 nuts (3/4") to deal with plus the air line (7/16" for the reducer fitting). I cut the airline flush with the fitting but made sure there is enough slack first. That shortens the line by almost an inch so make sure there's plenty slack, otherwise you have to fight the fitting. Wire brush the long stud threads. The bottom nuts are easy. At the top, that's where a skinny air gun became handy to make it a 5 seconds affair. My regular gun would not fit. I first tried with a regular wrech, not possible to break it loose. No access and no leverage. Just be safe. Here is all i needed to get it done:

[Guest Ray Davis]

2 hours ago, Ivan K said:

I think a tire plug would have worked well in my respective case if in a pinch.

Seems like it should, but a fella on IRV2 said he did that and it held ok until they got on the road.  His leak may have been in a bad spot though.

Thanks for posting the pictures and your description of replacing the bag.

[Trinidaddave]

Ivan, thanks for the detailed information.    I am not sure if I would tackle this job, but if I do I don’t want to cut any corners.

[Gary Cole]

Learned something new. I did not suspect that the bag sidewall was 1/4" thick. A large diameter coarse thread sheet metal screw would do to stop a leak temporarily on the road. Wouldn't hurt if it leaked a little as the air compressor could keep up with it. I haven't been leak free since 2005. One more leak probably wouldn't make much difference.

[jacwjames]

Different application and much more severe duty but we used these types of air bags on vibrating feeders in the mining and milling industry.  Different attachment setup as they used these to support the whole feeder, an I'm talking lots of weight.  The vibration action has to be pretty aggressive to get the crushed/broken rock to flow, they used large motors with an off balance type weight on the shaft, usually variable speed so the feeder can be adjusted for flow rate.   These would run 24/7 for weeks on end in some applications.   The airbags would last for years unless damaged by spillage and or extreme weight on the feeder and a poor operator. 

 

So with that in mind I have confidence in my +20 year old air bags that have probably seen the equivalent of a week of duty in the mines.  I inspected my bags closely last year, spraying them down with soapy water, good light, phone/camera.  Did not find any leaks and only minor external cracking. 

So I used a similar approach as Ivan,  I opted to buy 2 spares to carry and the tools to repair if needed.   Hope I never need them but available if I do.