Originally Posted by wch1940
Anyone know how to service the air dryer (and where it is located)?
Well Sir, it's located in a couple of different places on various coaches. It's not always in the same spot for all. And, contrary to popular belief, they're NOT ALL THE SAME. Servicing some, can be a bit more intense than others. Many think it's a simple job on all. Not so. Different models require different kits or, filter assemblies.
The first thing you need to do is, (1) either find yours on your coach and get the model number off of it. Or, (2) look at or in your paperwork/manuals etc. that came with the coach and see if you have any build sheets or, component lists that might spec out what model you have. Or, (3) you maybe could call your coach maker customer service line and if, they, like Winnebago and or Freightliner, have lists of what was installed when the coach was built, that would work too.
I just serviced my air dryer and, it was not simple "spin off and spin on" type service. Mine was/is tucked up behind the rear axle on the drivers side. There are TWO filters in mine. A large spin on that sits upside down and, another one down in the cavity below that spin on one. That spin on one on mine sits up against a ton of wires and other paraphernalia and, even if I could spin it off while the unit was mounted, it would knock a ton of debris down into that other chamber.
And, on some, the relief valve faces the mounting bracket and, if that's the case, even the instructions for replacing it, tell you that you have to remove the unit and bench service it.
In any case, it's not all that hard to take it down and, work on it, on the bench anyways. A couple of air hoses, some fair sized wrenches and, an electrical plug and, four 3/8" x 1" bolts and mine was off. The kit part number for ours was the DQ6026 which, includes two filters, a gasket, a new purge spout, and a relief valve. I got lucky and got it off ebay, brand new for $63.00 but, they normally hover around $130.00 or more. It depends on which model you have. Good luck, and surely PM me if you need info on it.
P.S. Below are a couple of pics of mine, on the bench for service.