CTS2
Junior Member
Posts: 70 Likes: 27
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Post by CTS2 on Sept 10, 2022 14:35:31 GMT -6
I have recently seen an airbag that exploded under prime mover. It didn't look particularly old or perished. Upon further inspection, the arm of the level height valve had become disconnected. Would this have caused the system to over pressurise, causing the airbag to explode, or should the airbag be able to withstand maximum system air pressure anyway, meaning the failure was bound to happen anyway?
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Post by northernfarmer on Sept 10, 2022 19:57:39 GMT -6
That is a very good question, for sure to attain that maximum pressure without the load that required the pressure at stock ride height the bags could have hyper extended out as far as they are allowed if the arm on the level valve flopped to the fill the air bag position given it had a free for all once the rod was disconnected. The risk for having bags extend out beyond where they should travel could put stress on the bottom of the bag ( I am speculating on that ) but also its the shocks that would come to the end of their travel and ether rip off their mounts or pull off a shock eye etc. There is a reason why air in the trailer at least should be dumped when unloading a trailer fast at a grain terminal and for that matter the truck as well unless one is careful not to dump too fast. I just don't know the answer if max pressure is enough to blow a bag in good condition but will say that I've used trucks for years that come up to 105 pounds of pressure due to overload although driving slow but not the 125/130 psi that the truck could ultimately fill an airbag up to.
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Post by kevlar on Sept 10, 2022 21:26:56 GMT -6
I would suspect that the bag was getting old or had a fault in it, they should be able to hold system air pressure and then some without blowing up . If it was drove fully extended and at full pressure, driving over uneven terrain would put a lot of pressure on it.
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Post by Beerwiser on Sept 11, 2022 11:24:29 GMT -6
Were you unloading when it happened? I have seen them pop when unloading equipment off a trailer when guys forget to dump them, but usually doesn't happen for things like unloading grain. But if the air bag was already maxed out and unloading into a decent capacity auger the chance is there.
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Post by SWMan on Sept 11, 2022 19:30:37 GMT -6
Maybe on uneven ground and all the bags pressured up but one hit the end of it's stroke first?
Or just another example of "they don't make em like they used to".
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Post by kevlar on Sept 11, 2022 21:38:32 GMT -6
I was just thinking, have any of you actually seen an airbag burst from dumping a load without dumping the air first? In all my years I never have, haven’t even seen a bag blow ever. I worked in construction for several years and the trucks used to dump gravel all day long and never dumped the air on the trucks, and lots of those loads were dumped with clamshells in the matter of seconds. I’m kind of thinking that shouldn’t happen, the shocks should stop the bag from over extending and the rapid loss of load would actually be a sudden drop in air pressure, should it not?
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Post by meskie on Sept 11, 2022 21:54:48 GMT -6
One guy who worked at the elevator said he had seen a couple shocks blown out from not dumping the air but they likely weren’t good to start with. I’ve blown out a couple bags on our one tandem truck while loading it…..it makes a Big Bang. After that happened i like to change them when they start looking kinda worn.
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Post by Oatking on Sept 12, 2022 5:55:36 GMT -6
Any body know if double air bag axils are less prone to blow out than single.
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Post by meskie on Sept 12, 2022 9:28:59 GMT -6
Any body know if double air bag axils are less prone to blow out than single. Your talking a kenworth 8 bag? If they aren’t kept clean the mud builds up around them and they wear holes in the bag. On the older ones anyway
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Post by kevlar on Sept 12, 2022 15:50:23 GMT -6
Any body know if double air bag axils are less prone to blow out than single. Not sure if they are more prone or not, but they do offer a more exciting experience the first few loads when you put a grain box on top of them!
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CTS2
Junior Member
Posts: 70 Likes: 27
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Post by CTS2 on Sept 16, 2022 6:13:55 GMT -6
Were you unloading when it happened? I have seen them pop when unloading equipment off a trailer when guys forget to dump them, but usually doesn't happen for things like unloading grain. But if the air bag was already maxed out and unloading into a decent capacity auger the chance is there. It wasn't unloading. It had been driving a few minutes previously, but was parked stationary on flat ground when the airbag blew out. Normally if the level valve arm disconnected, the airbags would deflate. But in this case I think the vertical rod had caught on some air lines after it became disconnected, holding it in the pressurise position. We will never know how long it had been like this.
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Post by shmiffy on Oct 8, 2022 1:11:03 GMT -6
Any body know if double air bag axils are less prone to blow out than single. KW 8 bag with the big airlines last along time. 10 years on a truck before I think of changing them.
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Post by Beerwiser on Oct 8, 2022 23:02:36 GMT -6
Well, I managed to blow a airbag on the freightshaker. Bought a couple of dry vans a few years ago and had one sink down to the kingpin. Anyhow I was using the truck airbags and a chain around the kingpin to the fifth wheel plate to get it up enough to get a jack under. I disconnected the leveling valve so I didn't have to climb in and out of the cab to drop the air and to give me a bit extra lift. It took me about 8 times of raising and reblocking etc. to get a jack under. Got the jack under and called it the day. By time I walked 400 yards back to the house to grab a beer and wait for supper I hear a boom. Knew exactly what happened. The bag that went seemed in good shape and I really think they can not handle full system pressure.
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Post by badaltitude on Oct 9, 2022 8:19:09 GMT -6
I've noticed on some of the trucks I've owned that the air suspension gauges will show an icon of an exploding bag at 80 psi.
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Post by northernfarmer on Oct 9, 2022 9:26:16 GMT -6
Beerwiser, it would be interesting to see where the bag blew out when you get a chance to change it out, if it blew in the area that the bag normally runs at and is curled under and gets that constant flex or if it blew out at the bottom end. Then again there is always a possibility there was a damaged spot for some reason on the bag.
badaltitude, what brand of truck was this that had that marking on the gauge and what was its normal bag pressure with a maximum legal load on the bags ?
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