09-17-2017, 12:28 PM
I found the same pattern that Bill is reporting in terms of variability. I'm also inclined to focus on the new air bag being somehow different now than the one on the other side (it could be the same part number and yet somehow stiffer of slightly different in shape).
If the when parked with the leveling off and the coach stays at the same height as when turned off then the air loss is not due to the new bag since it is holding air when isolated by the 6-pack valves. Likewise , if that corner of the coach drops when all the 6-pack valves are not energized, then the new bag installation probably is related to the air loss.
There is an instance in which in the travel mode you could have the front corner running low. If there was a leak in the air bag installation and there was a restriction in the flow of air between the HCV and the air bag via the TRAVEL solenoid valve then you could have the HCV unable to keep up until slightly low. This assumes the HCV progressively opens as it senses a low position - I do not know for sure if this is the case but I suspect it is. A quick test to see if a part of this scenario is happening is to do the leak test I mentioned above.
I have pondered long and hard regarding the weight carrying capability of an air bag and its relationship to ride height. What I've concluded is that weight on the individual front air bags has little influence on their respective heights at the shared air pressure coming from the HCV. The front air bags do not carry the same weight, there is a side to side disparity. For some coaches this difference is small and for others it is considerable and, yet, our coaches ride level in the travel mode. It seems to me that in the TRAVEL mode the rear ride height has a strong influence on the respective front heights, side to side. Given this, it also seems to me that if the bag can achieve close to the ride height of its opposite bag then it is unlikely to be the wrong size. I believe that raising that last inch is more a matter of increasing air volume than increasing air pressure. I admit that I've never tested this perspective with pressure gauges. I think in this case it's more likely that upon changing the air bag you started making measurements that you caused you to notice a situation you were previously unaware of and Bill's suggestion above could give you a more reliable understanding of what the case is. I'm convinced that something I said here is true, the problem is I'm not sure which part
If the when parked with the leveling off and the coach stays at the same height as when turned off then the air loss is not due to the new bag since it is holding air when isolated by the 6-pack valves. Likewise , if that corner of the coach drops when all the 6-pack valves are not energized, then the new bag installation probably is related to the air loss.
There is an instance in which in the travel mode you could have the front corner running low. If there was a leak in the air bag installation and there was a restriction in the flow of air between the HCV and the air bag via the TRAVEL solenoid valve then you could have the HCV unable to keep up until slightly low. This assumes the HCV progressively opens as it senses a low position - I do not know for sure if this is the case but I suspect it is. A quick test to see if a part of this scenario is happening is to do the leak test I mentioned above.
I have pondered long and hard regarding the weight carrying capability of an air bag and its relationship to ride height. What I've concluded is that weight on the individual front air bags has little influence on their respective heights at the shared air pressure coming from the HCV. The front air bags do not carry the same weight, there is a side to side disparity. For some coaches this difference is small and for others it is considerable and, yet, our coaches ride level in the travel mode. It seems to me that in the TRAVEL mode the rear ride height has a strong influence on the respective front heights, side to side. Given this, it also seems to me that if the bag can achieve close to the ride height of its opposite bag then it is unlikely to be the wrong size. I believe that raising that last inch is more a matter of increasing air volume than increasing air pressure. I admit that I've never tested this perspective with pressure gauges. I think in this case it's more likely that upon changing the air bag you started making measurements that you caused you to notice a situation you were previously unaware of and Bill's suggestion above could give you a more reliable understanding of what the case is. I'm convinced that something I said here is true, the problem is I'm not sure which part
Jon Kabbe
1993 coach 337 with Civic towed