[Wally Arntzen]

I really don't know what valves are activated when I flip the tag switch on the dash, but I do know that the air is depleted from the bags when I do it.
You can tell the difference of the empty bags when backing up with sharp turns. My friend at a bus repair garage informed me that you should always deplete the bags when backing up if making any turns which will allow you to get into a spot eaiser and also saves wear on the tag tires.
On the older coaches there is a lateral arm shock above the tag and on mine when I got the shock was bad and we had to replace it. My friend informed me that it was from long time backing without fliping the tag switch when using reverse.
The Prevost coaches have a tag system that lifts up the wheels when activated and the Newells dropping the air serves the same purpose.