I'm starting to tackle some age related issues and general maintenance. Trying to spend my coach-bucks carefully and prioritize . I'm including some photos of what the original bags look like. Also wondering if this is a do it yourself project for a novice such as myself.
Rears look like they'd be easier then the fronts. Maybe I could at least tackle those myself. By the photos can you tell if these are looking good for another year or should be at the top of the fix now list
I would say they look good for a long time yet, but I have not replaced mine either so will be interested on others replies.
JohnH
I read one of the previous posts and somebody said they had "rubber flaking off" for a couple of years before changing.Why
don't you get one or 2 bags for spares and carry them,you'll use them at some point.
Carry at least one new airbag and the tools to change it with. One of your rear airbags will leak eventually, probably while parked in a campground. At that point change all four of the rear airbags if you have the time / money. Start saving money to replace all four front airbags within the next year or two. The main thing though is to have a new airbag and tools with you wherever you go. It's an easy job that can be done in a parking lot or campground. You don't need physical strength or technical skills. It's four bolts and an air hose fitting. On some of them you'll have to remove the fender, which is also easy. There are dozens of people on this forum who have changed airbags and they'll help you with the details when the time comes.
If I replace a couple rears or all four I can keep one as a spare. Good idea.
My airbags looked worse than yours before the first one started leaking. They cost about $155 each on the internet and you've got 8 of them. I'd order one and carry it with me at all times. You'll also need a set of wrenches and a heavy duty bottle jack that's short enough to fit in beside the airbag.
Unless the 99 U270 is easier than a 99 U320 The fronts are a bear to change without pulling fenders or making windows in the panels. I just did all 8 of my U320 and I would not have had enough tools onboard to do them and I carry a lot of tools.
I dunno, I've only done airbag replacements on my U300 and it was very straightforward. Half of the airbags required removing the fenders, which was no big deal. I probably could have done all 8 of them in the same day if I had to.
Pulling fenders was on my do not do list as I am not a body man and don't want to mess up the appearance of the coach. Others have done it I know but resealing and making the seam trim look good requires a good caulking person, I am not.
This thread prompted me to order a spare today from Foretravel - for my 1991 U300 - priced at $97.22 without Motorcade discount.
I now can see why a U300 would be easier than a U320. The U300 doesn't have to deal with the front entry step recess and there might be other big differences. I only can see pictures of U300's don't have any experience with them.
Here is a link with lots of info about replacing the air springs. What makes it hard is that the nut on the hollow bolt that admits air into the bag is a fine thread; requires many turns with a wrench to remove and install. Air Bags (http://www.beamalarm.com/Documents/air_bags.html)
Firestone Air Springs are tuff unless you encounter road (debris) damage.
I did have a nail go through one with my Glide Ride 45' trailer. Best riding trailer I ever owned BTW.
Unless you are having to deal with weather checking and then only if they are leaking, I would leave them alone.
I have never seen or heard of one blowing out. The air ride hitch on my 40' trailer as had Air Springs (two) for 15 years,
living out in the weather and over 400K without issue.
A qualified tech giving it a once over every few years is a good idea.
Find a bus repair shop and give it a once over.
I would not blame tires, something is out of spec. pc
Many (most ?) of the OLD ('73-'78) GMC motorhomes have the original air bags.
A few years ago I said that I was going to wait until I had an air bag fail, but changed my mind. When the rubber started falling off and cord was showing, I installed new air bags just so I didn't have to deal with it in some remote spot. Cord is what provides the strength for the bag and when the rubber is gone the cord can wear quickly, just like on a tire. With a leaking bag you may have difficulty raising the coach enough to get safety chocks in place to remove the bag.
Which is why many GMCs, if left sitting for a while, will get the "sag of the bag."
I was told by Bernd Ramspeck (the Nac mechanic guru) that the rubber formulation changed in the 90's. The reason was that the tire rubber formulation was changed to accommodate federal regulations to one that would degrade over time in a landfill, and that Firestone used the same formulation on the air springs. That was supposedly rectified some time in the 2000's... Don't know if it is true, but it is a good story. ::)
Don