AD2 air dryer

[Melbo]

How easy is it to change out an AD2 to an AD9.  My AD2 began to purge every second or so during the recharge cycle and when I asked about a rebuild / service package I was told that I would be better to replace the AD2 with the AD9.  I have serviced the 2 in the past with good  results.  Is it worth the trouble or is the 9 that much better?  If the function is the same why change. Why not just service what I have.  I hate to ask (do not want to open a can of worms) but what are the general opinions on the bus board.

thanks

Melbo

[bevans6]

My AD2 is plumbed with all hard lines that would have to be reconfigured to fit an AD9.  Probably cut off, re-terminated and use flexible lines to the AD9 ports.  I thought it would be a lousy hard job to do.  FWIW I just bought a brand new AD2 purge valve rebuild kit from Bendix for around $20.  Still available.

[jmblake]

I replaced mine with a AD9 drier only because the can rusted through, Like Brian said it was a pain getting the air lines re plumbed but other than that pretty easy.
Jason

[luvrbus]

Fix your AD-2 it is so easy to service vs the the AD-9 if you go with the AD-9 watch the knocks off they sell on the E place watch the the terms " replacement or style" buy a Bendix more dollars but a better dryer a older bus doesn't need the drying capability of a AD-9 the AD-2 is more than adequate  ,tell Billie hi for us

[chessie4905]

If you decide to upgrade, you can change all or some of the lines to DOT nylon and appropriate fittings. Would make things easier in future, even with old one. If old hard line goes too far to it's connection point, you can cut out a piece and splice to nylon. Also nice that AD-9 is shorter, although fatter. If old one is in excellent shape, probably makes sense to keep it.Parts for 2 are available and prices are still reasonable, so I guess 6 of one, half dozen of the other.

[brmax]

All great comments on the options for you. I wanted to further promote to anyone doing this work. That the DOT apporved fittings are the best option, and with the approved plastic type lines the connector fitting will have the stainless or brass insert for the line that needs to be used, thus strengthening the connection. Hth

Good day
Floyd

[luvrbus]

If I was doing a AD-9 on a MCI I would by pass the lines the lines going to the AD-2 and mount the AD-9 in a different location,on MCI's the location up front is a terrible place for a air dryer to service IMO 

[PP]

A long time ago I thought that if I ever had problems with my air dryer I would exchange it out for an Ad-9. But now that I'm having problems and getting ready to remedy them, I've decided it will be much simpler and easier just to service the Ad-2 that I have. Now I just have to sneak under the bus when management isn't watching  or push it one more trip to our next destination where I can do moderate work. I do have a towing policy...

[luvrbus]

I really liked the AD-9 for a replacement for the AD-2 at first till I serviced a few,to many bolts and o-rings on the AD-9,the AD-4 is even worse   

[TomC]

I just got a knock off AD-9 from Freightliner. About half the cost of the Bendix rebuilt and you don't need a core to turn in. I'll see how it works in the future. Good Luck, TomC

[Melbo]

Well it seems the consensus is to service what I have.  I will be doing that directly.  I have a place that I have gotten all the necessary supplies before and I have a way to get the bus up in the air so I can work on it.  I agree the dryer is in an awkward place but it will have to stay there.  Billie says thank you Clifford and hi back. 

Melbo

[PP]

BIG THANK YOU TO BRIAN (Bevans6) for the suggestion to pump my brake a few times and get the air dryer in the closed valve position before shutting down the diesel. I got an opportunity this AM to take the bus on a short hop and when I fired it up (didn't even have time to preheat-50° ambient temp) she fired right off and aired up with no issues. Still going to service the air dryer soon, but that little trick seemed to worked this time.
Thanks, Will

[PP]

Just a quick followup here. I pumped the brakes until I got the air down to 90PSI when I parked the bus 2 days ago and this morning I heard the brake caliper bang as I was getting out of bed, it just now dropped to less than 60PSI. She's never held air this long before and I've owned her 10 yrs now. I figure after I service the air dryer she'll probably hold air forever  All the times I've crawled around looking for air leaks, I never suspected the purge valve. My bad.
Will

[Jim Eh.]

Another option is to upgrade to an AD-IP or some other spin on replaceable cartridge style/make dryer. Bendix is not the only player in the market.
Then the desiccant can be service in <10 minutes.

[TomC]

I had an AD-2 on my first truck and was easy to rebuild. I now have an AD-9 and it was old enough where the rebuild kit didn't match up. That's why I just replaced the whole thing. Good Luck, TomC