Do I use my alcohol evaporator?

Debo · November 14, 2014, 08:07:04 AM

Hi all. I have the old metal canister type alcohol evaporator in my 1981 MC9, and I'm wondering if there's any benefit to using it. Here's my situation - I live in a warm, but humid climate, but it can get below freezing. When I drain my tanks after a days run, it usually only spits out a few ounces of water. I don't have an air dryer installed. Would it be beneficial to put some alcohol in there for preventive maintenance, and if so, what kind of alcohol does one put in it? I've had the bus for about 5 years and put anything in it, but if you guys think it's worth messing with, I might start. Thanks in advance for any answers.

Oonrahnjay · November 14, 2014, 08:10:53 AM

Quote from: Debo on November 14, 2014, 08:07:04 AMHi all. I have the old metal canister type alcohol evaporator in my 1981 MC9, and I'm wondering if there's any benefit to using it. Here's my situation - I live in a warm, but humid climate, but it can get below freezing. When I drain my tanks after a days run, it usually only spits out a few ounces of water. I don't have an air dryer installed. Would it be beneficial to put some alcohol in there for preventive maintenance, and if so, what kind of alcohol does one put in it? I've had the bus for about 5 years and put anything in it, but if you guys think it's worth messing with, I might start. Thanks in advance for any answers.

Hi, Debo - do you ever drive in below-freezing temperatures?

akroyaleagle · November 14, 2014, 10:08:04 AM

Debo,

Go to any truck supply or most truck stops and get some brake line alcohol. Fill the canister, screw it back on and drive the bus. Everytime you apply the brakes, alcohol will be ingested into the brake lines and tanks.

It is really used to prevent brake line freezeup in cold weather, but what the heck, fill it up a couple of times when you're going on a trip and pull the alcohol through the system. Probably will clean up a lot of things! It's also pretty cheap.

luvrbus · November 14, 2014, 10:35:05 AM

Your MCI probably has a air dryer up front between axle you don't use alcohol with a air dryer or with certain valves and compressors lol where are all the Bendix school guys my instructor was passionate about not using alcohol

mung · November 14, 2014, 12:19:58 PM

I plan to use alcohol when I am working on my brakes, oh wait, that probably isn't the same as what you guys are talking about.

Debo · November 14, 2014, 12:56:45 PM

Thanks guys for the great answers. It's about like I thought. I guess it couldn't hurt because I know for certain that I don't have an air dryer, and it may clean things out a little. Bruce, I don't intentionally drive in below-freezing temperatures, but I might someday so I just wanted to see how you guys felt about them. I'll probably do it a time or two for any cleaning benefit, then again at some point of I'm driving in cold weather. That's not the plan though. I'm a shorts and flip flops kinda guy.

Oonrahnjay · November 14, 2014, 02:16:13 PM

Quote from: Debo on November 14, 2014, 12:56:45 PMThanks guys for the great answers. It's about like I thought. I guess it couldn't hurt because I know for certain that I don't have an air dryer, and it may clean things out a little. Bruce, I don't intentionally drive in below-freezing temperatures, but I might someday so I just wanted to see how you guys felt about them. I'll probably do it a time or two for any cleaning benefit, then again at some point of I'm driving in cold weather. That's not the plan though. I'm a shorts and flip flops kinda guy.

That's why I asked about what you plan to do. I also was taught same as Clifford in Bendix school that alcohol is bad for brake systems if you don't have an air dryer and totally lethal for an air dryer. If your out on a trip and it's the only way to get 300 miles down the road before a total blizzard hits, you can do it but expect it to loosen up contaminants (technically known as "crap" by highly trained experts like Clifford and me) which can clog stuff up; also, the alcohol can have bad effects on rubber seals and gaskets or damage items like the highly machined bores in master cylinders and inversion valves, etc.
Having heard what I did from the Bendix guy, I'd say that alcohol can work but only as a last resort. FAR better to get water out of your system before it gets cold -- and if you don't intend to drive in genuinely cold weather without an air dryer, make your plans so that you won't. It's just better to avoid alcohol if it's practical to do so -- even though it "works". (And definitely stay AWAY from it if you have an air dryer).
And as an old NC boy, I know about the shorts and flip flops!

HB of CJ · November 14, 2014, 02:28:48 PM

My old Crown Supercoach ex schoolie had a big decal on the dashboard that said ... "Drain Air Tanks Daily". I asked my HD truck mechanic friend, (a good friend to have) and he suggested just installing an air dryer thingie. I think it has a replaceable cartridge, but I am not sure. He also put on a thing that spit air every so often. He told me SW Oregon humid air and water in the air system during hot and cold winter do not mix. Seemed to work just fine. HB of CH (old coot) I forgot what it $cost$.

luvrbus · November 14, 2014, 02:37:16 PM

I had to go back to 1994 to find anything on alcohol from Bendix the process starts 2 weeks before freezing temperatures and uses 1 to 2 ounces a compressor hr, the way I read the bulletin it won't do much good parked and you use only methanol alcohol or the Bendix stuff that was in 1994

TomC · November 14, 2014, 02:58:41 PM

If you don't have an air/water separator, it is the number one thing to install to keep all of your air system from freezing and contaminates out since it filters the air also. It is so effective, Freightliner and Western Star installs them as standard on big trucks. Good Luck, TomC

luvrbus · November 14, 2014, 03:09:57 PM

The older MCI's have the E filter to collect the contaminates in the air system very seldom do they get changed now filters are hard to find I just helped a buddy change his over to the newer Bendix AF-3 filter on his MCI

chessie4905 · November 14, 2014, 03:33:42 PM

GM coach service manuals advise to leave air tank drain/s open overnight to drain all oil and accumulated sludge if practicable.
Every year we have members with air line/component issues after temps drop below 32 degrees. Like was stated. Alcohol isn't of much help after freezup because it cant get through the system to reach component. Air drier is the preferred item to have and regularly serviced and,of course,a nice heated shop.

brmax · November 14, 2014, 03:34:53 PM

I believe they recommend having any alcohol after the dryer/desiccant if plumbing.

Debo · November 15, 2014, 02:38:28 AM

Interesting thread... Ok, well after reading all of this, I'll probably just leave well enough alone and only plan on using alcohol (in the bus anyway) if I get in a situation where it's below freezing and I absolutely have to get somewhere.

I've read a lot here about air dryers, and I can see how it would be a very good thing, but my bus wasn't equipped with one - although it looks like there may be wiring run for one. There's a pigtail that comes out between the front wheels in the normal place to mount one, but no evidence that one was ever there. Something for the long-term list of things to add perhaps.

I'm also going to investigate an air/water separator. That sounds like a little higher priority in my situation. Thanks again guys.

akroyaleagle · November 15, 2014, 11:59:39 AM

Mine came from Eagle with the alcohol injection system.

I've had it over 18 years. I don't normally drive it in extreme cold conditions. I have driven it in -40 though.

I do every few years run a cannister of brake alcohol or whatever it's called through it. Never had any leaking seals or problems. Can't understand the reluctance to use a product clearly labeled "DOT approved" for what it is intended to do. Why would that damage any seals or lines?

When I use it, it will cause the accumulator (or whatever it is called , water separater?) on driver side behind the battery tray to trap a lot of tar like residue. When I drain that, it comes out through the drain tube. I remoted the drain to the side where it is easy to reach and drain it probably less than 6 times since I've had the bus. I removed it once and took it apart and cleaned it. Yuck!

I do not have an air dryer and that is fine with me.

My compressor doesn't "pop off" either. That would drive me nuts.

I have auto drains and like them. If they give someone problems, it's probably because they are gunked up.

Auto slack adjusters are wonderful also. They just have to be operated correctly. Occassionally, stop the bus with the brakes released and apply the brakes 5 or 6 times. They will adjust. I suspect most never do that. I also suspect that few ever put any airline lube in their air wipers. They work much smoother if you do!