I just had a random recollection here. When I was trucking with old trucks with no air dryers or a worn out compressor that blew snot real bad, draining tanks was a daily interesting experience. Then when time marched on to more modern trucks and stuff that was not so worn out, I don't think I ever got a drop of water or anything else out of them, and I would drain them when I thought of it, but nothing ever came out. I speculate that the air dryer was doing such a good job there was so little water that it would not condense in the tanks at all, but I always wondered if you in more humid climates still get water out of modern trucks with air dryers.
Dryers remove about about 85 to 90% of moisture when dryer has been serviced regularly. Spin-on AD-IS type dryers get serviced more simply because it's easier. The AD-9's not so much, we change out cartridges every fall and never have freeze-up's or other issues. Truck Shop
I'd say that air dryers only keep tanks relatively dry provdided they are serviced properly. My current location we are pretty keen on servicing dryers but even so the primary air tanks still accumulate a certain amount of water.
My area is fairly dry most of the year, with periods in the spring/fall that get some humidity, but nothing like where *real* humidity occurs. My formative years were on air systems with no dryers, and I've carried one habit with compressor systems, shop or truck - when you're finished for the day, open all the drain petcocks until you fire 'em for another day's work. Not a lot of air circulates in those tanks, but just some helps a lot. I too swap my AD-9's filter out every fall.
Is generally above 75% humidity here during summer with quite a few 85+% days, no air dryer and you will see tracks from anything that purges or exhausts, on the units with driers will see the moisture content discharged to hard surface pavement but generally only a hint of moisture in tank volumes over a weeks time.
Same here only the RH is usually in the teens, you will usually see a damp spot where the air dryer purged on the pavement. But I have never gotten anything out of the tank on a unit that has a properly functioning compressor (not blowing quarts of oil, etc.)
Your supposed to drain tanks and change filters lol All joking aside the only time I had moisture problems on an air system was changing tires in the rain and then I still didn't get much out when I drained the tank
We run all AD-9 dryers. Couple of the farm trucks have been neglected in the past, dryer doesn't get a second look until the purge valve fails, and they never have a drop of water in the tanks.
Biggest problem I have is winter salt spashing up... in one year a new one looks like hell.
Company truck is an ‘01 KW W900. Company is on top of servicing their equipment. I’ll tug on the drain cords every pretrip. Here in damp western Washington, I’ve never seen any buildup in any of the tanks. Darryl
So a little off topic but I still run some nice old junk with ad2 and ad4 dryers. Went to get a cartridge and kit for the ad4, not available. So $600 later I have a somewhat modern ad9. Anybody have the same experience?
Last AD4 I changed a cartridge on was 15 years ago. I thought it was a nicer design than the AD9 what with the 4 bolts instead of having to horse it out with a big ole strap wrench. Hard to imagine there are none for sale though.
Found a few on Fleabay, more on Find-It-Parts pages but I suspect are fast obsolescing where Bendix will not further service them, age factor and need to sell NEW patterns.
Around here, our truck parts guys have been known to take a Bendix dryer for core on a reman, on sale $179 exchange.
I just got a reman AD-9 priced about like shimmy1. $600 sounds awfully steep doyleX, is there some kind of California extra tax on that? I think the reman was only a little more than a dessicant cartridge, and a rebuild kit for the purge valve, check valve, and a new heater. For just a little more I didn't feel it was worth rebuilding mine. Pulled off the lines and just swapped the whole thing.
I just bought two AD-9 dryers for $142 apiece-reman, I think new was $265. Agree with CO 600 is way out of the park. Truck Shop
This was a a year or so ago. If I remember right they hit me hard for the core. Sad thing is I think its still on the shelf.