Tag Axle Valve?

[ajhaig]

We've been parked at a camp ground (Fort McDowell just outside of Scottsdale, AZ - nice place) for a little over a day. Tonight I was standing next to the bus when suddenly I heard a loud air sound coming from the rear of the bus. It was the same sound that I hear when I raise the tag axle. The bus didn't seem to move noticeably.

In thinking about the sound, I've noticed that when I start the bus after it's been parked for a few days the tag axle indicator light on the dashboard comes on. The light goes off as the bus airs up.

Could I have some sort of faulty valve?

Thanks again.

AJ

P.S. This guy joined us for breakfast!

[Jerry Winchester]

AJ,

Not to hijack your tag axle post (when the air gets too low the tag axle dumps), I am headed to Phoenix the day after Christmas and have been pondering about a place to park for a few days. We are going to the bowl game on New Years Eve in Tempe, but for all the gazillion parks in the Phoenix area, most seem like snow bird places and very few seem to be set up for folks to come hang out for a few days and move on.

Any suggestions would be appreciated.

[ajhaig]

Jerry,

We are in Eagle View RV Resort, Fort McDowell (I think there may be several RV parks in Fort McDowell). I would recommend this place, it's quiet, clean and relatively new. It is on an Indian reservation and connected with a casino (the casino is about a mile or so away). I think it is in Big Rigs. We did the ride to Tempe today, it's a straight shot down route 87.

The place seems pretty empty now, but they told us that they get very busy after the holidays.

There is an slim chance that we will still be here through Christmas.

AJ

[Joe Cannarozzi]

You have an air leak. Right before the pressure drops to the threshold of activating that valve the valve itself will begin to exhaust and the sound of air will get more prevalent and loud. Around 40 psi or so.

[Jon Wehrenberg]

AJ.....some coaches of an earlier vintage had a system design that required a specific auxiliary air system pressure to hold some valves closed. Typically if the pressure dropped below that required to hold the valve closed against the spring plunger pressure (somewhere around 30, but Joe may have the more accurate number) the valve would open and air in the rear would dump, usually allowing the bus to settle down.

I don't know what year Prevost redesigned the system, but I think your bus precedes that design change.

It is only a problem if the aux air system loses pressure, or if you have system air leaks, even minor ones. Prevost was aware of the glitch that showed up as the coaches began to age, and there was a change that they could make at the service centers to eliminate that design error. I may not have it completely correct because a lot of owners had the upgrade done and that was a long time ago and my memory has faded.

[Ray Davis]

My '93 did the exact same when the aux system got low enough. There is a retrofit kit from Prevost, however it's very expensive. My recollection was that it was somewhere in the $2000-$2500 region.

I chose to live with it.


Ray