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Another Air Bag Question
So I ordered air bags when they where on sale. Started with the tag. Well the tag had two different bags on it. One is the same # as the drive bags. the other one is a 630259. This matches what prevost sent me. Thought all was good. But when I set the old next to the new one it is about 3.5″ taller than the old one. (the same part # top of the bag and the side) Well thought I would try it anyway. Went in ok and aired it up all good. But when I lifted the tag it folded up like a dish rag. See pics. Now has anyone heard of a bad batch of bags from goodyear? My coach is a 05 40ft. Shouldn’t it have the same tag bags as a 45ft? I know the 45s in that year is using a 630151. I do not think the bag is going to last long folding over when I lift the tag.
Any advice would be greatly appreciated
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11 Replies
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The plot thickens.
Brock, the air bags should have an industry trade number molded into the side of the rubber somewhere.
I doubt the same trade number is on both bags which if I am correct suggests Prevost’s problem with the bags may in part be caused by someone mislabeling them at Prevost.
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I just checked. Both the old and new bags have the same #566-22-3-079 molded into them. Only thing different is the date code. Am I correct in assuming the bag should not wrinkle up like that?
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566-22-3-079 identifies just the bellows. According to Goodyear, those bellows are only used on the 1R11-244, so that matches. Other bellows are used on more than one spring assembly. I attached a screen shot from the Goodyear catalog below. None of this explains your oddball situation. If the one on the right is fully extended and unmodified, Jon may be on to something with a possible error at the manufacturer. Good luck. 🙂
edit: I just noticed in your first picture that the base plate with the air fittings seems wider on the spring to the left, at least relative to the diameter of the bellows. If the plates are different diameters, that also supports the mislabeling theory.
1984 96" with 8V92TA
(remodeled Liberty Coach)
Greenwood, MO -
Here are the dimensions for your air spring, also from the Goodyear catalog:
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So a little update. Spoke with Prevost Nashville. They looked at my picks and said they could not explain why it is wrinkling up but the bag measured in correct. They think when I get some miles on the bag it will expand an stop wrinkling.
They told me they are using this bag on all tag axles. #630259 (45’and 40’XLII MTH)
I thought that I had read some of you guys are using the 630151 on your tags?
Could someone tell me what you have put on the tag?
Also the top and bottom plates do measure the same.
I now have a email out to Goodyear tech to see what they think.
Thanks
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Brock,
There was a time when I pissed off a whole lot of Prevost people regarding their use of both the 259 and 260 air bags. When the wrong air bag ends up on an axle it screws up the level low system because usually the bus will not raise to the extent previously possible, and that is what alerted me and I started digging.
It turned out some how in the Prevost system numbers got transposed in bills of material or air springs got mislabeled with the wrong Prevost part number, but since that happened more than 10 years ago it seemed like we all got past the issue.
However your photos show two different air bags with the same Prevost part number, and more confusing the same trade numbers. The change in height is an obvious reason why some coaches are not going to be able to get the full range of motion the level low system is supposed to provide.
But the issue goes beyond that, maybe not in this case, but the potential exists and it concerns me. Our axle weights are established based on the planned allowable weight limits. From those limits the engineers balance everything by selecting air bag sizes and brake chamber sizes. If those sizes are changed from the originals the potential exists to have an axle carry more or less weight than planned, and that affects the brakes that have to have more or less force applied so all braking forces are balanced. An axle with too little weight could have premature brake lock up (or ABS engagement) or not enough braking force applied.
Over the years our brake chamber sizes and friction material surface area have changed to maintain that delicate balance between axle weights and braking forces needed. The wrong air bags can upset that balance.
If anyone suggests air bags stretch or grow or shrink after being used a while have no clue. I’m so far out of it now I don’t know what is really required but when I see two totally different air bags side to side with the same part number I know something is wrong. Seriously wrong.
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Jon
I totally agree with you something seems very wrong. May I ask what bags you have on your tag? The tech in Nashville said it should be a 630259 for all Motorhomes
The other thing that seems strange to me is the 630259 has a travel of 8.5 to 22 percent inches. The 8.5 seems correct this stops the lifting arm just before it hits the housing. But the 22″ seems like way to much. That’s almost 14″ of travel. The axle will be hanging on the shock long before the bag is extended. And this is just a guess but I would think the airbag and the weight of axle combined would win that battle. If it could happen. Like when shop lifts the coach from the drive axle to change a tag tire. I have seen it done. -
I’ll go check my logs and give you part numbers.
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45 foot, 2005 chassis, XLII, 2 slides, 18,000# steer axle. I provided that because what might be acceptable for my coach might not work on others.
Steer axle…….630239
Drive axle…….630104
Tag axle……….630151
The air bags were not obtained without a great deal of difficulty. 2 of the three were wrong on the initial order, with all problems related to the size of the threaded air fitting not fitting in the hole in the top plate, or the orientation of the threaded studs, 90 degrees from where they should have been.
The numbers above are what is now on the coach and they work.
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Mine is 104’s on drive and 259’s on both steer and tag. Straight front axle on mine not IFS. 40XL
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Frt- 630259
Drive- 630260
Tag-630259
XLII 45 foot
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