Air Dryer Rebuild

My coach has a Bendix AD-9 air dryer. It requires periodic maintenance in order to keep the air system dry. This maintenance will help in assuring that your air system is not contaminated with moisture. This project required removing the passenger side rear duals to gain access. Remember Country Coach places their OTR air conditioning condenser in an area that would normally be open, so off with the tires.

I am sharing this with the members to show that the dryer can be easily rebuilt, but a new dryer assembly can be purchased instead. As I recall, you can rebuild the dryer for appox. 1/2 the cost of new.

Attachment 3800
This is what the air dryer looks like when first removed from bus. Coated with miles of road grit and oil.

Attachment 3799
After cleaning the air dryer, I removed all the parts to replaced. This photo shows the new Bendix Dryer Cartridge in place and ready to replace the air dryer cover.

Attachment 3804
This is the soft seat that was removed from the purge valve. As you can see, a groove had worn into the rubber. It needed replacement,

Attachment 3803
For my nickel, replacing the check valve is a great maintenance item to assure pneumatic system integrity. The check valve assures that the air does not 'back flow' from the raw air tank. This leak could be viewed as a aux air system leak. Since no check valves are present in the raw air tank which sources the aux air tank, any leak here would depressure the aux tank also.

Attachment 3801

Here is the air dryer, cleaned, rebuilt and ready for installation.

Rebuilding the air dryer is a good maintenance exercise. The hardest part was removing the duals for access. As I recall, Bendix states that using their air dryer cartridge will give good service for three years. The way our coaches are used, changing on Bendix three year recommendation is more than adequate.

I hope this help others that might want to do this project.

Hector