Dean, below came from Engineer Mike's parts list.
"43) Front Air Bag Part #, 1998 Coach: Triangle: AS-8311, or Firestone: W01 358 9039, or Goodyear: 1R12-095, or Holland: 90557023. Ride Height control valves on front: Haldex 90054007. This is a common part and can be got at most truck parts suppliers. Rear Air Bag: for the AD-200-7 rear suspension used on early coaches is safholland (Neway) 90557161, Triangle 8492, Firestone W01-358-9482. For some reason not many distributors stock this. 2006 M.Y. Rear air bag part# 90557311, mfgr probably Holland."
Tim & Ruth
Alpine Coach 1999 40FDS, 350 ISC