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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Stormcloud on September 25, 2008, 06:03:06 PM

Title: BENDIX AIR DRYER
Post by: Stormcloud on September 25, 2008, 06:03:06 PM
Hi,all:

I'm going to have an air dryer installed on my MCI7...the mechanic said it likely came equipped with one when built, (he never saw one without an installed dryer) but was removed somewhere along the way.

He suggests a Bendix AD-9 dryer.

I havent used this mechanic before. He seems to know his stuff, and he maintains a small fleet of (at the moment) Prevosts, but he says he likely has more time on MCIs than he wants to admit:)

Is an AD-9 my best choice? What parts of an air dryer are 'consumable'? Do I need to carry replacement valve/filter?
Thanks for all suggestions.

Mark
Title: Re: BENDIX AIR DRYER
Post by: luvrbus on September 25, 2008, 06:12:08 PM
That is a good dryer and no need to carry parts  just service it, some say I do mine to often I do it once a year and never have problems
Title: Re: BENDIX AIR DRYER
Post by: Ncbob on September 25, 2008, 06:15:54 PM
Hi Mark,

I have an AD9 on my 40 year old MC5A and am perfectly happy with it. I also carry a spare element for it but haven't found the need for it after 2 years.

Based on my installation, which will probably be endorsed by the pillars of our community, you should install it before the 'ping tank' in the rear engine compartment as possible. The purpose of the air dryer is to remove excess moisture before it gets to the first tank. Manual tank pulls, to drain the 'wet' tank are ideal too.

With that advice I'll leave the rest to the experts.

cordially,

NCbob
Title: Re: BENDIX AIR DRYER
Post by: Dreamscape on September 25, 2008, 06:43:22 PM
I have an AD9 also, just not installed yet. ;D

I know, I know, it's on the list OK! ;)

Let me know how you come out.


Paul
Title: Re: BENDIX AIR DRYER
Post by: niles500 on September 26, 2008, 02:33:30 AM
AD-9 is the current "state of the art"- best to go with the most current - longest sevice life - FWIW
Title: Re: BENDIX AIR DRYER
Post by: JackConrad on September 26, 2008, 05:09:34 AM
I would install it after the ping tank and before the wet tank. The pink tank also traps oil vapors that are in the air leaving the compressor (this is why the ping tank is to be drained daily).  You want the oil vapor out of the air before it goes to the drier.  Jack
Title: Re: BENDIX AIR DRYER
Post by: Busted Knuckle on September 26, 2008, 06:04:25 AM
Quote from: JackConrad on September 26, 2008, 05:09:34 AM
I would install it after the ping tank and before the wet tank. The pink tank also traps oil vapors that are in the air leaving the compressor (this is why the ping tank is to be drained daily).  You want the oil vapor out of the air before it goes to the drier.  Jack

I agree with Jack 100%!  Also FWIW on all MCI's I have ever worked on the air dryer is usually mounted at the front behind the front axle. Which means the air goes from the compressor - to the ping tank- to the dryer at the front- then is plumbed back to the respective areas.

An AD-9 is a quite capable and common dryer.

FWIW ;D  BK  ;D
Title: Re: BENDIX AIR DRYER
Post by: TomC on September 26, 2008, 07:29:19 AM
AD-9 is still available to this day on Freightliners.  Another is the AD-IP which has a spin on desiccant filter that needs to be replaced once a year.  I have the AD-4 on my Kenworth truck, which has to be rebuilt about every 200,000 miles.  But-it tells you when to rebuild it because it starts spitting often.  Good Luck, TomC
Title: Re: BENDIX AIR DRYER
Post by: Dreamscape on September 26, 2008, 08:17:26 AM
I was studying my manuals for my Eagle last night and saw that they call it a "Pink Tank"...... ??? :o ;)

Spell Check was not available back then...Hee hee

Paul
Title: Re: BENDIX AIR DRYER
Post by: buswarrior on September 26, 2008, 06:01:25 PM
I concur, an AD9 is a fine choice and well supported by parts vendors everywhere.

Be sure that your mechanic knows the mileage of pipe required between the air drier and the compressor if he is installing it in the engine room.

Remember, mechanics usually work on existing installs, they don't "design" and may not understand all the requirments.

If he is installing up front in the traditional location, the pipe length takes care of itself.

Check for empty mounts up front, the job may be easier than originally thought!

happy coaching!
buswarrior
Title: Re: BENDIX AIR DRYER
Post by: Dreamscape on October 11, 2008, 06:04:08 AM
Quote from: JackConrad on September 26, 2008, 05:09:34 AM
I would install it after the ping tank and before the wet tank. The pink tank also traps oil vapors that are in the air leaving the compressor (this is why the ping tank is to be drained daily).  You want the oil vapor out of the air before it goes to the drier.  Jack

I had not thought of this untill I read your comment Jack!

When I do my rear brakes I am going to install the AD 9 at that time.

My question is this, what type of hose do I use after the ping to the dryer back to the wet tank?

I will be installing the dryer in the LH corner by the electrical panel in the rear of our Eagle. So the hose length won't be too bad.

Thanks,

Paul
Title: Re: BENDIX AIR DRYER
Post by: JackConrad on October 11, 2008, 06:22:15 AM
I can only tell you what is on our bus (was on it when we purchased it). The hose from the compressor to the ping tank has a braided SS jacket abd crimped on fittings. From the ping tank to the dryer is a rubber hose with crimped on fittings. From dryer to wet tank (only a few inches) is a metal line with compression type fittings.  Jack
Title: Re: BENDIX AIR DRYER
Post by: Dreamscape on October 11, 2008, 06:32:09 AM
Thanks Jack,

The Bendix site does not specify any type, only minimum size of 3/16" IS dia.

I was thinking that 1/2" rubber would work.

Title: Re: BENDIX AIR DRYER
Post by: JackConrad on October 11, 2008, 07:15:52 AM
Just looking at the outside diameter, I would say our air line from compressor to ping tank and from ping tank to air dryer is 5/8" inside diameter. Metal line from dryer to wet tank also appears to be 5/8",  Jack
Title: Re: BENDIX AIR DRYER
Post by: luvrbus on October 11, 2008, 07:17:34 AM
Paul, use DOT approved poly tubing will last longer than rubber and cheaper
Title: Re: BENDIX AIR DRYER
Post by: Dreamscape on October 11, 2008, 08:33:48 AM
Quote from: luvrbus on October 11, 2008, 07:17:34 AM
Paul, use DOT approved poly tubing will last longer than rubber and cheaper

I like that word....cheaper.... ;D

I'll check my local NAPA and see what they have, I'll take the dryer and match the fittings too.

Is this the push lok type? Or is it used with a compression fittings with ferrule?

Title: Re: BENDIX AIR DRYER
Post by: John316 on October 11, 2008, 10:36:47 AM
Just make sure that the dryer is relatively accessible. MCI (on the DL3, I can't speak for other models) puts theirs in front of the axle on the front wall. There is some room to work and to change the cartridge. We replace our cartridge before every winter, since that is when you most need to prevent water in the lines. Also make sure that if your bus is 24 volt, the dryer is 24 volt. We had a shop install a new dryer on ours one time and they installed a typical truck dryer , which was 12 volt, and the heater instantly blew up when the bus was started ;). So verify that the heater is 24 volt. That heater will save you a lot of headaches.

Just my .0002

HTH

God Bless,

John
Title: Re: BENDIX AIR DRYER
Post by: Dreamscape on October 11, 2008, 10:49:14 AM
John316,

Thanks for those words of wisdom.

I am installing the dryer in the old A/C condenser bay on our 01 Eagle, it's empty, lots of room. I wanted to put it where the 05's have it but not enough room. The plumbing would be better there anyway as I have to tie the control hose to the unloader side of the governor, then plumb the in from the ping tank, out to the wet tank.

It is 12v like the coach, so I'm good to go.  ;)

Paul
Title: Re: BENDIX AIR DRYER
Post by: John316 on October 11, 2008, 11:07:48 AM
Wow Paul, you have a great place for your dryer!!! I wish ours was where you are putting yours. You should at least put a lot of things in your way and stand on your head when you service the dryer so you can experience our pain that we go through to service ours. LOL

God bless,

John
Title: Re: BENDIX AIR DRYER
Post by: JackConrad on October 11, 2008, 04:35:20 PM
I would check DOT tubing temerature ratings before using it from compressor to ping tank, that section get to hot to touch.  Jack
Title: Re: BENDIX AIR DRYER
Post by: luvrbus on October 11, 2008, 04:54:34 PM
I am still looking for the ping tank everybody talks about,mine comes from the compressor with a stainless hose to a cooling loop then to the dryer with metal tubing and from the dryer to the wet tank with DOT Poly this is they way Eagle did it  good luck
Title: Re: BENDIX AIR DRYER
Post by: Busted Knuckle on October 11, 2008, 06:11:08 PM
Clifford on MCI and some others there is a small tank that looks like about a 6-8" piece of pipe with a end cap that has a drain tap in the bottom. Which has a line running from it going to the curb side access door for daily draining! ;D  BK  ;D
Title: Re: BENDIX AIR DRYER
Post by: Dreamscape on October 11, 2008, 06:56:27 PM
The ping tank on our Eagle 01 is located in front of the tag on a bulkhead. Braided hose comes from the compressor to the bottom, then a rubber hose from the top to the wet tank. It has a small valve on the bottom for draining. I can barely reach mine from outside the coach. It's only about 8" tall.

Actually our 01 never did have a dryer, at least I have not seen any remnants or any mounts. My manual does not call out one either. Maybe on your 05 Clifford, they suspended the ping tank and put the drier in it's place. Just a wild guess.

Most of the tubing I have come across in doing a search today was rated at 150 F.

Title: Re: BENDIX AIR DRYER
Post by: luvrbus on October 11, 2008, 07:10:51 PM
Paul, I found on the Bendix site that is a option for the system but can not find out the purpose of it.In my manuals for the 05,10,15 and the model 20 there is no reference to one in any schematic I have for Eagles also I could not find any reference to one in the H 41 Prevost manuals, but I would still like to know the purpose of it. 

good luck
Title: Re: BENDIX AIR DRYER
Post by: Dallas on October 11, 2008, 07:16:16 PM
the ping tank is also called the compressor muffler among other things, if that helps.

DF
Title: Re: BENDIX AIR DRYER
Post by: Dreamscape on October 11, 2008, 08:45:27 PM
Clifford,

My guess, and it's only a guess, is this small device collects not only moisture but any oil. There is nothing to take apart and clean from what I see. I'm sure it also cools down the air after the compressor.

(A few posts back I said the hose from the compressor came into the bottom of the ping tank, that is incorrect, it comes in the side and line to the wet tank is on top). :-[

You pose a very interesting question.
Title: Re: BENDIX AIR DRYER
Post by: jackhartjr on October 11, 2008, 08:58:33 PM
NCBob, you said, "With that advice I'll leave the rest to the experts."

If we took a poll here on this board I think everyone would count you among the Experts here too! ;D

Jack
Title: Re: BENDIX AIR DRYER
Post by: Busted Knuckle on October 12, 2008, 12:12:12 AM
Quote from: jackhartjr on October 11, 2008, 08:58:33 PM
NCBob, you said, "With that advice I'll leave the rest to the experts."

If we took a poll here on this board I think everyone would count you among the Experts here too! ;D

Jack


At least one of the most "experienced"! LOL! ;D   BK  ;D