Air Dryer Question

NJT5047 · May 24, 2011, 06:08:00 PM

Thanks Brian, I replaced an AD-4 with an AD-9, the whole dryer unit. That's why the heater plug is different. The AD-4 had a single terminal heater without a thermostat, although AD-4s came in thermo and non-thermo applications. On my MC9 it worked with the PAX heat control. Turn on the PAX heat and the dryer heater was powered up.
I needed the plug for the new dryer. Steve ID'd the plug design, I found it as a retail item on Aircraft Spruce. Used on aircraft wiring. Not too expensive.

Cary, the dryer can be repaired without removing the can. Just drop the base out and replace the filter/separator and rebuild the base which includes the purge valve. If you're not getting water or oil from the air tank drains, it's working (albeit and leaking). As you say, if it's really old, it may be corroded, but likely that only the purge or check valve is failing.
I have an AD-2 filter/separator, "O" rings, and a purge valve repair kit that I bought thinking that I had an AD-2. Wrong. I'm going list them on Ebay one of these days unless someone wants them. FYI, I'll post a pix in the event you haven't seen an AD-2 filter assembly.
JR

Cary and Don · May 24, 2011, 07:04:30 PM

How much do you want for them? We are trying to catch up on the maitenance on everything.

Don and Cary
1973 Eagle 05
GMC 4107
Neoplan AN340

belfert · May 24, 2011, 07:15:52 PM

Serviceability in place depends on the dryer model and how the dryer is installed. I have to remove my AD-9 to service it because the bolts that hold the cover on also attach it to the bus. The space is so narrow I don't know how I would service it even if the mounting bolts weren't an issue.

luvrbus · May 24, 2011, 07:33:55 PM

The Ad 2 on a Eagle is a snap to service 3 bolts and a snap ring you do it standing up

luvrbus · May 25, 2011, 08:24:43 AM

Jr, found the wiring diagram for replacing the AD 4 with the AD 9 1 wire from the ignition with a 5 amp fuse (for 24 v) the other to a chassis ground the harness can be bought from Ryder Fleet or any truck supply

good luck

NJT5047 · May 25, 2011, 07:55:13 PM

Thanks much! Reckon I could wire it into the old system which would input 24V whenever the coach heat is on? That would defeat the thermostat, but it should work....? With the location of the dryer, tapping into an ignition switched wouldn't be difficult. The worst part of the job would be pulling the #%&* spare tire back out. I just put it back in.
I'd like to have an Alcoa for a spare, but got steels on the inner duals and don't think the studs are long enough to run two Alcoas...bummer. Aluminum is so much easier to work with.
I'd bet a dryer harness gets frequently damaged or worn from dinking with it. Have to check with Fleet Service locally. I'll add that going into a truck repair shop and saying the word "bus" often isn't greeted with joy and smiles. Part of my problem is that I do my own work and they know it.
For S&Gs, does this look like the plug Steve indentified. The two pin plug looks the same...and I'd guess that the "wht2" is a short for White WPT-2?

JR

NJT5047 · May 25, 2011, 07:58:46 PM

Quote from: Cary and Don on May 24, 2011, 07:04:30 PM
How much do you want for them? We are trying to catch up on the maitenance on everything.

$50 bucks?

Where are you guys located?

JR

Cary and Don · May 26, 2011, 08:12:34 PM

Sent private email. We are in California.

Don and Cary
1973 Eagle 05
GMC 4107
Neoplan AN340

NJT5047 · June 07, 2011, 06:38:40 PM

FWIW, the replacement air dryer solved the fizz problem. 300 miles on the bus last week and all went perfect...including both ACs! The temps were near 100* and NO shade where we were, other than under the awning...and had a good crowd under there!
It's amazing how well the 20 plus year old bus runs and drives. I gripe about working on it, but I doubt the bus is anywhere near as problematic as are most large S&S motorhomes.

JR