Quote Originally Posted by gmcbuffalo View Post
I have been replacing the air bags in the rear of my bus and I have the bus up on Jon's stands. The other day I was working under it sit behind the differential when the for some reason I heard and felt air coming out of the one Norgren (I think the top one) and all three bags on the drivers side went empty. PANIC. But the bus didn't drop because of the stands. You never know what may cause the suspension to drop.

I could understand why the tags would dump air if the pressure got low, but all three bags on one side? The passenger side three bags were still rock hard. The bus is level on the stands so I don't think it has anything to do with the road leveling controls. Level selector was in Drive and the key was off.
Very interesting!

If you heard air escaping from one of the five port Norgren mounted on the forward bulkhead, in front of the differential, during this deflation of the airbags, then the Norgren either intermittently failed or the pilot valve in the pneumatic cabinet failed or gave the signal to the Norgren to dump the air. I am one that believes the Norgren valves used in our busses are very high integrity valves. If you look up the specification, the number of cycles are rated in the thousands (can't remember the exact number). Far greater than the usual RV owner will ever cycle the valves. The biggest issue I have found is that after many years of operation in the hostile environment under the bus, the o'rings will shrink and leaks will occur.

Concerning the leak, if your Prevost is of the vintage that when low aux pressure results in a tag axle release, then their will be a momentary lose of air pressure. But it should not have deflated the air bags completely?

The best thing is you had you bus sitting on Jon's jack stands. I use mine anytime I crawl under the bus, every time! I carry mine in the rig. Of all the tools I have acquired for the rig, the jack stands are rated at the top of the list. Jon should get the POG "Safety Award", if we have one, at Austin.

Thanks Jon for taking the time and effort to build the Jack Stands!!!

Hector