Moisture in brake system

[1944mb]

Getting ready to go into winter, and was curious your guys input regarding moisture/air brake antifreeze in a m35A2. Will the air brake line antifreeze bother the air pak? Is there a specific spot that it is best added? Working formerly as a mechanic I've rebuilt quite a few heavy truck air dryers. After rebuilding and changing the descicant I always added air line antifreeze to the system. The results of not doing that in northern areas is diastrous...I cant seem to find the pic, but had a pic of a semi's trailer where the brake cans wouldn't release cause they froze-his last axle's tires were shaved almost to the rims! Just wanted to insure trouble free operation in the winter months. Thought/advice??

 

[rustystud]

Getting ready to go into winter, and was curious your guys input regarding moisture/air brake antifreeze in a m35A2. Will the air brake line antifreeze bother the air pak? Is there a specific spot that it is best added? Working formerly as a mechanic I've rebuilt quite a few heavy truck air dryers. After rebuilding and changing the descicant I always added air line antifreeze to the system. The results of not doing that in northern areas is diastrous...I cant seem to find the pic, but had a pic of a semi's trailer where the brake cans wouldn't release cause they froze-his last axle's tires were shaved almost to the rims! Just wanted to insure trouble free operation in the winter months. Thought/advice??

The deuce doesn't need any air-line anti-freeze if you drain the tanks like the TM says to do. I would not add any "ethylene" based fluid in the air system period. In fact most all manufactures have totally gone away from air-line anti-freezes due to the caustic effects it has on the air valves. If your in a really cold place and your concerned about freezing then get a good air-dryer with a heater unit like the "Bendix AD-9" .

 

[tommys2patrick]

What are your thoughts about the alcohol bottle hooked to the compressor on a deuce? Not worth getting back to working condition? I drain my tanks and the fluid is usually clear, sometimes a tiny amount of black fluid included. Hardly enough to stain the driveway.

 

[rustystud]

What are your thoughts about the alcohol bottle hooked to the compressor on a deuce? Not worth getting back to working condition? I drain my tanks and the fluid is usually clear, sometimes a tiny amount of black fluid included. Hardly enough to stain the driveway.

I wouldn't do it. My old 1954 REO's had them but like I said you would be better served with a air-dryer. At the transit agency in the early 1990's we would run "ethylene alcohol" in some of the buses (those built in the 1970's that did not have air-dryers on them) . Then a few months later we would replace half the air-valves. By 1995 all the buses had good air-dryers on them and we never used alcohol again.

 

[tommys2patrick]

Thanks Rustystud. Always value your opinion. Guess I will start checking into a modern airdryer upgrade. Air is pretty dry up here in the mountains so its probably not a giant problem so far.

 

[1944mb]

Thanks rusty stud. We serviced a fleet of buses, that were all modern(replaced on a schedule) and serviced the air dryers frequently, on a schedule. We however, when the mercury dropped to -20- -30F, always had problems with one or two. We also used to work on a lot of over the road trucks. I say used to, cause I no longer auto mechanic for a living. You could always tell who, didn't maintain their air dryers and brake system...Our issues from the buses, I'm not sure if its from short trips, but I guess most yellow buses have that issue. We never had any air valve issues that I'm aware of. At any rate on a true air brake system, its easy enough to back the brakes off on an axle and limp it home, but wanted to make sure on the a2. I guess if no one has had problems I can run it and see. I won't use it much in the winter I would imagine, but we will see. Thanks for your thoughts.

 

[rustystud]

Thanks rusty stud. We serviced a fleet of buses, that were all modern(replaced on a schedule) and serviced the air dryers frequently, on a schedule. We however, when the mercury dropped to -20- -30F, always had problems with one or two. We also used to work on a lot of over the road trucks. I say used to, cause I no longer auto mechanic for a living. You could always tell who, didn't maintain their air dryers and brake system...Our issues from the buses, I'm not sure if its from short trips, but I guess most yellow buses have that issue. We never had any air valve issues that I'm aware of. At any rate on a true air brake system, its easy enough to back the brakes off on an axle and limp it home, but wanted to make sure on the a2. I guess if no one has had problems I can run it and see. I won't use it much in the winter I would imagine, but we will see. Thanks for your thoughts.

What most people don't understand about the air-dryers desiccant is that it has a "shelf" life. It starts when it is first exposed to the atmosphere. You need to replace it every year if driven daily or the very least every three years even if it just sets. That is the major reason I went with the "Bendix AD-9" dryer instead of the military unit. The replacement desiccant is only $30.00 compared to $ 100.00 to $180.00 for the spin-on filter of the Haldex unit. They both need to be replaced on the same schedule so why pay more then you have to ?

 

[DDoyle]

A bigger concern is moisture in the hydraulic side of the system - especially if you are using silicone brake fluid. Water will not mix with the silicone (unlike older fluid), resulting in slugs of water - which can turn to plugs of water in severe cold.

Regards,
David Doyle
www.DavidDoyleBooks.com

 

[rustystud]

A bigger concern is moisture in the hydraulic side of the system - especially if you are using silicone brake fluid. Water will not mix with the silicone (unlike older fluid), resulting in slugs of water - which can turn to plugs of water in severe cold.

Regards,
David Doyle
www.DavidDoyleBooks.com

That is why you are suppose to bleed out the brakes every two years. I don't believe in completely draining all the fluid, but a little bit out of each wheel cylinder (and master cylinder and air-packs) is perfectly fine. This keeps the water from pooling there.

 

[st8drumz]

Sorry to bump this thread but do you not, then, advise driving a deuce with no air dryer in single-digit temps, even with purging the tanks religiously? What kind of brake failure is possible? Will they lock up or just not engage (or both?)

 

[rustystud]

OK let me see if I got your question right. Your saying you shouldn't run a deuce without an air-dryer in extreme cold conditions, correct ? You can run it fine a long as your up on the maintenance. Of course if there is some water in the system then it will freeze and can cause a lack of braking. So at start-up you need to really go over your truck as it is warming up and make sure "all" systems are working OK. For me having an air-dryer is just extra security and less worry.