[Richard]

Jon,

I think you may have the true root cause, in that the airbags are near capacity. On both tag axle coaches I have experience with it takes about 80 to 90 psi to " float" the coach. When you said you were seeing air bag pressures at 110 and 120 then that was a big clue. If you ever replace the bags some research may be in order to see if a slightly larger diameter bag would fit.

Not that any of you need this explanation but here is the math behind the air bag. The air bag lifting force is directly related to it's diameter and the air bag pressure. So if the air bag diameter is 6 inches, that results in a pi®squared. Or (6/2)squared X pi = 28.27 square inches. Now multiply 28.27 sq inches times 100 pounds per square inch to give a lifting force in this example of 2800 pounds . Of course this is just an example. But to illustrate just how sensitive the force is to diameter, let's make the bag 1/2 inch larger in diameter. 6.5/2 squared X pi = 33.18 sq inches. At the same air pressure of 100 pounds the lifting force is increased to 3300 pounds just by increasing the diameter of the bag by 1/2 inch.

Sorry for the lecture, the point is that when replacing air bags it is important that they are the same size or you can create suspension imbalance issues.

I don't know why the radius arm bushings do not have zerk fittings on them, but it's something to think about. I might try that before I would pull the bushings out.