Suspension Air Bags

Just had our four air bags replaced at FCCC in Gaffney on our 2004 National Tropical. $400 labor and about $1300 total.

I just replaced the rear air bag (springs) on my coach. We did the fronts last November and the rear a few weeks ago. We also replaced the front air bags on the Gilling chassis with solid axle. We had a pit available to us. I am not sure we could have done it without the pit. The front was independent suspension. Most of the work was done from the top after we remove the wheels, but we need to pull more air line to reconnect the air bags, that required releasing some clamps from underneath. We spent a day on each side and that included the parts run. Second side was faster. Air lines were what took a lot of time until we figure out it out.

On the rear we removed the wheels to get to the air bag mounting bolts. We worked from both the pit and wheel well to get the air bags out and in. There were 2 on each side. Again it took a day for each side.

What we learned:
Getting the air line off the fitting was impossible. There is a stainless nipple on the inside of the fitting that is sort of pressed in to the fitting, the ferrule crimps the air line to the nipple and we could not get it off the fitting. We cut the air line at the fitting nut, and then removed the fitting. The fitting had to come off to get the mounting nut off. Once the fitting was off we were able to cut the ferrule off the air line and remove it, then it was cleaned up so it could be reused on the new air bag.

We spent a lot of time installing the air lines on the front. The trick we found that worked the best was assembling the fitting with a short piece of air line and tighting the nut until the ferrule can't move, then slide short piece of air line out and the air line in then tighten the nut to crimp the ferrule. We bought new ferrules, nuts, splices and air line at the truck store. With all that being said I would consider using DOT approved Push/Pull fitting. (Google "dot push to connect air fittings ") Theses fitting have O-ring to seal the air line. You simply push the clean air line in and it locks in place. On Gillings chassis the air fitting on the air bag were difficult to get to so we found an easier location and spliced the air line using the Push/Pull fittings. On my coach the air lines were 1/2 inch in the front and 3/8 inch in the rear. The Gilling's front were 1/4 inch. We went to get parts after we had one of the new air bag installed.

On the rear we did one side at a time by jacking one side at a time. It would have worked better to jack both sides. That would have allowed the axle to drop farther and the air bags would have come out and gone back in easier.

We were able to collapse the air bag, (remove the plastic cap) then put the plastic cap back on and it would stay collapse for a few minutes. This helped during installation.

The replacement of the air bags on the Gilling chassis was more interesting. The air bags are mounted to plates. The upper mounting plates were not a problem but lower mounting plates were a little convoluted. Two of the air bag mounting bolts are covered by the axle. It looked like you could unbolt the mounting plate from the axle perch and the air bag would come out. But that didn't work. The mounting plate has slots in it to prevent the axle mounting bolts from turning while they are tightened. But during the factory assembly, they tack welded one axle mounting bolt to the plate. We had to drop the axle to get to all the air bag mounting bolts.

My coach has front and rear Ridewell suspensions. We found the manufactures label plates and emailed Ridewell that information. They provide the part numbers for the airbags.

FWIW, those "air bags" are really called "Air Springs", although most of us here typically refer to them as "air bags".

The fronts are not that difficult to change of you're good with a wrench and have decent mechanical skills.

VERY IMPORTANT NOTE: Anytime you're working on the air suspension system, you must have your have your MH supported not only with your leveling system jacks by also with good heavy duty jack stands! (You can get a pair of 12 Ton Jack Stands at Harbor Freight for just a little over $100.)

zweible wrote:
My bad... new to this DP stuff. Someone told me it was a workhorse chassis. Should look in the manuals before asking questions. It is a freightliner chassis. Typical 2000 Bounder 36S. My apologies for my misinformation. Dang noobs! hehe

Now you're finally on track and even though I haven't done so, I would think that changing the air bags on a chassis such as this wouldn't be so bad and probably a whole lot easier, than if it was a P30 gasser, with the air bags inside the coil springs.
Just depends on you and with some, it could be major vs what's a piece of cake for others.

Give Freightliner (the factory in Gaffney) a call with your VIN. They can give you the PN.

Freightliner 800 385-4357

My bad... new to this DP stuff. Someone told me it was a workhorse chassis. Should look in the manuals before asking questions. It is a freightliner chassis. Typical 2000 Bounder 36S. My apologies for my misinformation. Dang noobs! hehe

Yup, saw the Workhorse diesel pusher chassis prototype summer of 2008 at a Caterpillar RV Engine Owners Club Rally in Bloomington, IL (just east of Caterpillar HQ in Peoria, IL).

Workhorse did not make a diesel until 2010. Either the mfg. date is wrong or it is not a workhorse.

Sorry, got me confused.

Was not aware that Workhorse produced any DP chassis in 2000. Yes, am aware that they did some later.

So, if Workhorse, contact Workhorse for the PN's.

Freightliner was the large chassis manufacturer of DP chassis at that time.

These are the suspension air bags in a 36 foot diesel pusher with air suspension. There are no springs or coils, the air bags are the main suspension. After looking at them, I think it would be better left to a professional to change them out. Thanks all for trying to help!

Dan