AD-9 Air Dryer rebuild, documentation, parts

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One of the more common items that require service in birds is the air dryer if so equipped. From the early 90's up to the last LX /I's the air dryer is typically an AD-9. Although the manual states every 2 years, experience has shown you could double that easily in an RV provided your entire air system is up to snuff. Here's a quick how to, the first time it took me 2 1/2 hours from start to finish and that included vehicle blocking to final air system testing. The air dryer is usually located forward of the drive axle, curb side up top near the frame rails.
1) BLOCK the bus BEFORE you go underneath. the HWH levelers ARE NOT acceptable ALONE. You need REDUNDANCY like hardwood under the frame rails, jack stands AND the levelers.see 3 systems.......you only have ONE life and you CANNOT make a mistake here! I use all three... Also CHOCK the wheels, the brake is only on the DRIVE axle, DO NOT lift it off the ground!!!!!!!! You can usually get underneath without taking all the wheels off the ground.
2) Once the system is blocked and chocked, you can air it down, and go have coffee while it completes
3) Once it is aired down utilize the attached service data manual and follow the step by step procedure..pretty straight forward.
4) Once you are completed, fire up the bus and air it up, LEAVE the redundant blocking and chocking system in place, then you can inspect your work for leaks, etc. Remove the blocking and chocking system ONLY after your final inspection.

TIPs:
1) I source all my maintenance parts usually from these sites:
http://www.anythingtruck.com/category/ht...o2000.html
http://www.fleetoilandtrucksupply.com/5007/dept
http://www.ryderfleetproducts.com/ryder/...tDetail.do
Order online, ship to the house, DONE! If you have a favorite go to truck parts supply house, they will also either stock or get you what you need as these are pretty common parts on large RV''s and class 8 trucks.
2) The first time I did this, I purchased a NEW purge valve, so I would have a spare. I rebuilt the old one and threw it in my spare parts draw. Then I rotate them. I also have a spare in case a fellow member is at a rally and in need! Worth at least a replacement in the mail AND a few ADULT beverages! :-)
3) Pay particular attention to what the manual states about separating the air dryer cartridge from air dryer base plate once you removed the air dryer from the bus and separate the base plate and cartridge from the canister cover. How to secure the base plate PROPERLY so you can remove the cartridge on the base plate. If you do not do this properly you could break the base plate in a table vice, etc., then more $$$$$$$........... I use a standard Strap wrench to remove and install the cartridge once I separate the canister from the base plate.

Good luck and PLEASE exercise EXTREME caution when working under the bus!