The air bag is already full when loaded.  When you dump it is letting air out to maintain ride hieght, maybe not fast enough.  How is it going to "blow" when you are not putting air in it. 

 Can you over extend them.   I mean you could do that if one axle is coming up on the road and the other is alot lower than the front. and then you would compress the front bags and that would be over pressurized right?

I am not following you guys on why you dump your air.

None of our trucks have gauges, what do they run for psi,  80?