BENDIX AIR DRYER AD-4

[johns4104s]

Would this dryer do the job if I installed it on my 1981 MCI 9? Somehow the bus does not have one?.

Thanks

John

[Dreamscape]

Hey John,

Are you sure? It's normally mounted in the front on an MCI.

I'd go with an AD-9 if I were you. Easier to maintain from what I've heard. I installed one on our Eagle and haven't had to do anything yet, so I'm just passing along what I've learned. We didn't have a drier, it was an option in 1968.

Paul

[Tom Y]

John, Not sure but that may be what was on there when new. I see a AD-4 and a 9 on Ebay. I think my 5 has a AD-2 but would have to look.  Tom Y

[NewbeeMC9]

Would this dryer do the job if I installed it on my 1981 MCI 9? Somehow the bus does not have one?.

Thanks

John

Look between the front wheels on the forward bulkhead,  Mine has an AD-9 now and it is a lot quieter than the old one(AD3 IIRC).     Check prices and parts availability also.

[belfert]

I was over at a truck parts place last Saturday and they had new AD-9s for $180.  I thought that seemed like a good price.  I didn't get a chance to ask if it could be optained in a 24 volt version.  (For the heater in the purge valve.)  I would go with the Ad-9 if adding an air dryer.  They are very standard and everybody sells parts plus a mechanic could fix one in his sleep.

I see the going price on Ebay for an AD-9 is right around $170 or a little less for an aftermarket unit.  There is a used one bidding at $15, but you'll need to rebuild the purge valve and replace the cartridge at minimum.  You'll also need to buy or make a mounting bracket.  I see there is even an aftermarket model for $130 new.  The seller claims he is overstocked.

I also see a new 24 volt purge valve for $25 I might grab as a spare.  They are a lot more than that at the truck parts place.  I like how the seller claims it is for Freightliner, Mack, Volvo when they use 12 volt.

[NewbeeMC9]

The the only electric is the heater and you can get 12v or 24v.  HTH

[luvrbus]

John, check with Doyle he paid 35.00 for a AD-9  it looked new but I forgot where he bought it,any model will work for you the old AD-2 is a hard one to beat


good luck

[TexasBorderDude]

Yepo John, I got it from Gary B in Vegas.  The desiccant cartridge was about $20... Sonny helped me install it (actually he did it!)  put it after the ping tank and at least 6' to 8'  away from the compressor to dissipate the heat.  Get the best bargain you can find regardless of model and make sure you can get the cartridge.

dg

[Paso One]

Would this dryer do the job if I installed it on my 1981 MCI 9? Somehow the bus does not have one?.

Look between the front wheels on the forward bulkhead,  Mine has an AD-9 now and it is a lot quieter than the old one(AD3 IIRC).     

Someone posted awhile back on re-locating the air dryer to a more conveinant spot for servicing.

Under the bus on the bulkhead or in the middle somewhere is fine when you have access to a pit,  but for the average guy thats not always available.

The person mentioned above relocated it to somewhere near the back.

There was also pictures posted by dezeldave on his 54 where I believe he mounted it in the engine compartment closer to the compresssor than recomended but easily serviced.

[Dreamscape]

This is where we installed one on our 01 Eagle. I know it's an MCI thread but it's still a drier install.

Not sure where in an MCI you can mount it, just food for thought.

The air line come out of the compressor, over to the ping tank on the opposite side then back the the drier. I installled a switch for the heater with an LED so I can see it if it's on, that is if I remember to look!

[luvrbus]

Eagle has always mounted the air dryer in the engine compartment without problems.
Mine is on the drivers side at the back on the 05 close to what Paul's setup is and easy to service.
Model 10 and 15 are in lower corner of the passeners side.



good luck

[belfert]

The the only electric is the heater and you can get 12v or 24v.  HTH

Correct that only the heater is 12 volt or 24 volt, but most of the new ones will be 12 volt and not 24 volt.  A lot of places may not stock the 24 volt version.  This might not matter if you never had a drier and can run a 12 volt line to it instead of 24 volt.  Most of the ones on Ebay seem to be 12 volt although some of the places selling new ones might have 24 volt models.

You don't even have to hook up the heater if you never intend to drive in freezing weather, but what happens when you have that mid winter emergency and have to make a drive into cold weather?

[belfert]

My AD-9 is in about the most inconvenient place possible for servicing.  It is up underneath the bus in a little space maybe 15 inches wide.  I had a heck of a time getting enough leverage with a wrench to remove the hoses going to it to remove it for servicing.  It is such a bad job I might pay someone with a hoist or pit to do it next time.

It doesn't appear the original owner had ever serviced the air dryer as all the bolts and stuff still had paint on them like they had never been disassembled for servicing.

[bevans6]

My MCI is wired so that the air dryer heater comes on when the coach heating fan is on, same switch.  Stud 49 in the front panel, and a 3 amp in-line fuse.

Brian

[belfert]

I thought the purge valve heaters are thermostatic?  Don't they typically get power all the time when the vehicle is running?

On an MC5 the air dryer could be a later add-on.