ad-4 or ad-9 on model 15 eagle?

[white-eagle]

looks like an AD-4 to me, but the parts house says they haven't been used since late 80's.  mine is supposedly a 1991.  i just want to make sure i order the right part, so i only have to climb under their once?

never changed the dessicant before, which is why i'm changing it now.  as far as i know, no trouble, but i'd rather change it here than on the road.

anyone got a definitive answer, or do i have to get under it and wipe off the grease just to read the label?

yes, ACE, i am lazy and don't like to get dirty 

[SmoothJazz]

The Eagle parts books show that it was an AD-4.

[luvrbus]

Tom,if it is a factory install on the passengers side lower corner in the engine compartment it is a AD-4 good luck and have you found the stop light problem yet

[white-eagle]

luvrbus, you're gettin to be the answer man, although not quite as quick as smoothjazz.  thanks for the answers.
my manual is a cd from coach info, which is supposed to be model 10/15 and it shows ad2 which i knew was not right.

i'll order the dessicant kit.

no, i have not found the light problem yet.  need time to get under the bus and listen to all the possible noises then start it up.  don't think i have leaks that are too bad, but something is causing the park brake relay to turn the light on, which lights the brake lights on the back all the time. on occasion, they do go out, but i have not figured out what wire is loose?

[Busted Knuckle]

most parts guys don't know squat about what was or is used when or how on buses! They might about trucks sometimes. But truck an buses are different animals even though they are somewhat similar appearing! FWIW !   BK 

[niles500]

AD-4's have been in use at LEAST to 1992 and I believe a lot longer - FWIW

[SmoothJazz]

Eagle used the AD-4 air dryer as late as 1994 and probably for some time thereafter.