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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: WEC4104 on February 06, 2007, 10:27:00 AM

Title: Frozen air lines ?
Post by: WEC4104 on February 06, 2007, 10:27:00 AM
Although our recent blast of artic air in Pennsylvania may seem like nothing to our friends in the great white north, hitting single digits (Fahrenheit) nightly is sure plenty cold for me.  ...and it brings with it some other interesting issues.

Over the weekend I decided to wake my 4104 from hibernation and take her out for some exercise. An engine block heater with a freshly inframed 6-71 is a wonderful thing. At 18F degreees, she fired right up without even a hint of smoke. (grin)

So there I sit in the driver's seat waiting for the air pressure to come up.  wait .... wait.... wait... Soon, it became apparent that my air pressure needle wasn't moving off zero, nor did it have any intention of doing so.  (disappearing grin)  A few more minutes of idling, and it was time to face the facts: I'm not going anywhere, and I turn the ENGINE RUN switch to OFF.   Duh. Without air pressure she keeps purring right along.  Put her in gear, let the clutch out, intentional stall.

Fortunately, I was at home with no immediate need to go anywhere. Just an aborted joy ride. But now looking back on things, I seemed to recall that it did the exact same thing once last winter.

My guess is I have ice in my compressed air lines somewhere, which brings me to a bunch of questions

Is this a problem others have encountered?

I seem to remember finding a can of air line antifreeze stuff left in one of the bays by the previous owner.  Haven't ever used any in the 6 years I have owned her, though. Do you guys use the stuff, and exactly what do you do with it?  Somebody educate me, please.


Title: Re: Frozen air lines ?
Post by: Nick Badame Refrig/ACC on February 06, 2007, 10:50:11 AM
Hi Wayne,

I know my dad went through that a couple times with his 4104.   I remember that he would always bleed off the

moisture from the system through the storage tanks to keep that from happening. Unfortunatly, you may have

to wait until what is frozen, to thaugh out before you can solve the problem. And I beleve there is something that

goes into the system to help combat the low temps...?? not sure what it is called.   Ask Luke.

Good Luck

Title: Re: Frozen air lines ?
Post by: gumpy on February 06, 2007, 11:02:09 AM
Used to be pretty common. Then they invented air dryers.

Does your bus have an air dryer?  Has it been serviced lately?

If it doesn't have one, do you regularly drain your tanks?

I'm going to suggest you also learn how to manually shut down the engine using the fuel shutoff lever rather than stalling it in gear. I have to think putting that kind of torque on non-moving parts can't be good for them, especially when they get that cold.

Title: Re: Frozen air lines ?
Post by: WEC4104 on February 06, 2007, 12:48:02 PM
Thanks for the input Nick & Craig.  To answer some of the questions, I don't believe I have an air dryer or if I do, it is certainly well hidden somewhere.  I do have tank drains, and although I make a point of draining them periodically, I don't do it every trip.  I only ever get small amounts of liquid out, and if there is pressure in the tank when I drain it, what comes out is more like a mist than a stream.

I don't have the tanks in front of me at the moment, but if I recall correctly, the only fitting at the bottom of the tank is the drain. All other connections are higher up.  So even if I had a couple of tablespoons of water lying in the bottom of the tank, I'm not picturing how that would block the air flow and prevent filling of the tank.  Maybe water collects somewhere else?

If if ever does get above freezing, like maybe around May, I'll certainly make a point of draining them. In the meantime I'll keep checking this thread to see if anyone can provide any more info on the air line antifreeze stuff and how it gets put into the air system.  If the answers do not turn up here, I can place that call to Luke.

Title: Re: Frozen air lines ?
Post by: Busted Knuckle on February 06, 2007, 01:54:06 PM
Do you know where the fresh air intake is for your compressor?  ;D If so take the air line antifreeze you have , open the bottle and get it as close to the open air intake as possible. It should draw it in by suction, but sometimes you have to form a funnel or such and pour it in to get it in! Once it goes into the compessor it'll be forced thru the lines and clear a path where ever the blockage is!
BK  ;D

Title: Re: Frozen air lines ?
Post by: Nick Badame Refrig/ACC on February 06, 2007, 02:03:35 PM
Hay Wayne,

Here is a link to info on a Bendix  air dryer for you to read up on.



Title: Re: Frozen air lines ?
Post by: D+C4106 on February 06, 2007, 03:33:56 PM
An interesting subject,  would anyone have an idea of the cost to add this to a 4106 ?  or is this too large to get into the engine compartment?   Does an air dryer solve all moisture concerns in the air system?    Denis

Title: Re: Frozen air lines ?
Post by: JimC on February 06, 2007, 03:39:39 PM
The air dryer in my 4106 is located in the bay under the drivers seat. seems to work fine from that location. If you have one, you would know it, it pops off occasionally when it hits its limit.

Title: Re: Frozen air lines ?
Post by: D+C4106 on February 06, 2007, 03:43:30 PM
Hey Jim,  Is yours the size of the Bendix shown below?  How well does that fit the compartment?  At the front tank,   is it connected to the entire air system?     Denis

Title: Re: Frozen air lines ?
Post by: NJT 5573 on February 06, 2007, 05:31:49 PM
WEC, When you drain the air tanks, they need to drain until the mist is gone not just the water you can see. I will leave my valve cracked open and drive for a couple hours before winter sets in. The bottle of air brake alcohol is to be used in a couple of different ways. Before the cold weather sets in take the line off the compressor that goes to the wet tank. (its the only pressure line there) Hold the line up in the air and pour half the bottle of alcohol into the line. Make sure the tank valve is closed so you don't pour the alcohol on the ground. It will run into the wet tank and work its way thru out the air system. Use the wipers brakes etc. and after 8+ hrs you can drain the system. If you do that once or twice before winter comes, you won,t have a freeze problem all winter, just keep the tanks drained at the end of each use. The other use for that alcohol is in an emergency. It goes in the same place, (pressure line to tanks) Put it in now and it will thaw the lines out, and you should be fine Wa

Title: Re: Frozen air lines ?
Post by: Dallas on February 06, 2007, 06:19:15 PM

Here's a thought, since you have a 4104,

It probably still has the aircompressor muffler on it. It should be found close to the compressor on the main air line from the compressor. It should also have a petcock on the bottom of it.
It is there to quiet down the compressor pulses and also capture some of the water/oil stuff on the way to the wet tank. If you haven't drained it, it is most likely full of crud and is probably frozen solid. If it is, it won't let ANY air from the compressor to the tanks.
Try heating it up with a propane torch and open the petcock to drain the crap out of it.

Who knows, you may get lucky!

Or not.


Title: Re: Frozen air lines ?
Post by: jeepme on February 06, 2007, 06:53:48 PM
My 4104 has a plastic bottle mounted next to the air compressor that you pour the air line antifreeze in. It slowly sucks it in. The previous owner put a label on the dash that instructs you to check it every 2000 miles. I've only been putting it in during the winter.

Jason Whitaker
'59 4104

Title: Re: Frozen air lines ?
Post by: Fredward on February 06, 2007, 08:01:03 PM
I have an air chuck between the muffler (after the compressor) before the wet tank on my MC-5 that I use for airing up the system before startup and to connect my emergency electric compressor. This fall, I drained all four tanks and then dumped a bottle of air brake alcohol into a portable air tank; pumped it up to 100 psi, turned it upside down and plugged it into the air chuck thereby forcing alcohol into the wet tank and throughout the system. Then fired up the Detroit and took her for a ride to distribute the alcohol through the system. Haven't really used it in the cold more than once so I'm not sure it helped but it sure seemed like a great idea to me  :)

Another guy told me not to use that alcohol because it dries out the seals and airbags etc. etc. Has anyone heard that?


Title: Re: Frozen air lines ?
Post by: gus on February 06, 2007, 08:27:19 PM

You could have aired up the system with shop air, preferably at the front aux tank under the driver.


I'm not positive but I think alcohol will dry seals. One thing I do know for sure is it will cause a lot of rust.

Title: Re: Frozen air lines ?
Post by: Beatenbo on February 06, 2007, 09:25:28 PM
Years ago I had several GMs 4106 2 4107s that didn't have air dryer like my MCIs. There used to be a contraption that fit in engine compartment that went inline in air system with an alcohol container that evaporated the moisture .  Used to work pretty good, don't know if they are still available.

Title: Re: Frozen air lines ?
Post by: tekebird on February 07, 2007, 03:12:30 PM
Luke has Alcohol Evaporators in Stock last I checked.  Stone Age simple and every truck stop sells the stuff.

No Maint just refilling

Title: Re: Frozen air lines ?
Post by: LUKE at US COACH on February 07, 2007, 04:59:31 PM
Hi Wayne & Folks:

When I was operating buses, most of which were older GM's not equipped with air driers, we installed the alcohol evaporator kits as described by JEEPME, BEATENBO & TEKEBIRD.

Here in N.J. about the first of Octber we would fill the container in the engine compartment.  We would perform a regular draining of the wet tank, along with the "ping tank", (which a writer described), and is at the end of the air compressor discharge hose, mounted on the right side of the engine bulkhead (when the coach was built).  I say "when the coach was built", as some of these buses have been through a bunch of hands and there is no telling what is original and what has been modified!!!

How does the kit work??  Every time the compressor cycles, it quirts a small amount of alcohol into the air system. It collects water &sludge and routes it to the wet tank.

The addition of an alcohol evaporator is substantially less expensive than the addition of an air drier and requires "no maintenance", just filling, whereas an air drier has to be maintained in order to be effective. And yes we do have the alchohol kits in stock.

I Hope this HELPS!!!!

Happy & SAFE!!! Bussin' to ALL.


Title: Re: Frozen air lines ?
Post by: WEC4104 on February 07, 2007, 08:38:00 PM
Thanks to all that have responded. As always, lots of good information to chew on.

I don't think I will take the step to add the big air dryer unit. Sounds like it would be nice to have, but I'd have trouble justifying it.  On the other hand, the alcohol canister approach certainly sounds like it is my best (and simplest)  long term solution. I have been thinking more about cold weather uses for the bus, similar to Jerry H's post a few weeks ago about a ski trip to the Pocono Mountains.

Short term, I probably am going to wait out some of this weather. It isn't supposed to be above freezing here until the start of next week (and then only barely).  Much as it would solve my problem, I don't see myself out freezing my butt off installing the canister system if I have no immediate need to go anywhere. When it gets a tad warmer, I will redrain the tanks and also see if Dallas' suggestion helps me.

FWIW, I did a few minutes of research on air brake antifreeze on-line.  I found there are two types of alcohol used Methanol and Isopropyl.  Methanol is better at lowering the freezing point, but is more prone to dry out seals. Isopropyl is less affective at really cold temps, but is easier of seals.  I think both are offered with rust inhibitor additives.

Luke: I want to keep the canister system in mind as either a DIY project for me, or for the next time my 4104 visits your shop. By the way, the rebuild your shop did is running real well.