In case anyone cares: I just replaced my now-10yrs+-of-age compressed air dryer. I disassembled the old one and found -sure enough- it probably needed replacing. Easy: One bolt removes the entire thing and one electrical plug plus tubing connections sets it free. Rumor has it the electrical heating element (external, exposed to elements and road mist) gets crudded up and becomes faulty, but mine was okay. If you have the original dryer, think about replacing it even though you have (surely!) replaced the two filters regularly. Bought it from Spartan, BTW.