Answer:
Improve
My advice would be to convert to a passive system. Most air suspensions have a life expectency of 5-7 years before you start running into trouble. Getting the conversion kit is a permanent fix to any problems you may be having with the air system. I recently got a conversion kit from Strutmasters. You should check out their website, www.strutmasters.com. They were very helpful and made sure I got the right product!
I have a 98 Ford Expedition and bought a conversion kit from Strumaters and would recommend this to everyone. I really enjoy the ride and I do not have to keep pouring money into my vehicle with Air problems. So check them out and see what they have for you. The customer service team was really informative and helped with the entire process.
The Complete Solution of Your Ford Expedition Suspension : http://www.strutmasters.com/ford-expedition-suspension-parts-s/76.htm