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Old 07-04-2015, 09:47 PM   #1
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Draining Air brakes

I was reading through manuals and videos etc.

Is it necessary/suggested to drain air brake storage tanks when you don't be driving for a while? If so is there a tutorial?

Asking before I start opening valves all willy nilly.
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Old 07-04-2015, 10:32 PM   #2
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When you compress the outside air, any humidity in the air condenses as water. When you get water in your air tanks, there is danger of it getting into the lines to the wheels and freezing or causing other mischief.

It is a good practice every day to open the valves at the bottom of all the air tanks to spit out the water until there is just air coming out. Sometimes this is a petcock that takes a quarter turn, other times there is a cable you can reach and pull from the side of the truck, kind of like an overhead air horn cable.

I haven't heard of any reason to drain all the air when not running a vehicle for a while. I even worked on some Macks that would not stop the engine when turning the key off unless there is air pressure built up. The first time this got me was a surprise.

Apparently, the operator had shut down the engine and then gone underneath and left the air drain valve open on the truck that needed radio work. When I finished working on the truck, I discovered I had to go under the running truck, shut the petcock, and wait with the key off for the engine to stop.

So that story points both ways. Mack designed the truck to be shut down with pressure in the tanks, but the operator made a practice of draining them. Either way, make sure any water present spits all out when you open the valves to do your pre-trip checks.
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Old 07-04-2015, 10:34 PM   #3
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If your brake system doesn't have an air dryer, then yes, it is good to drain your system on a regular basis to release trapped water.
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Old 07-04-2015, 10:34 PM   #4
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Quote:
Originally Posted by Redbear View Post
When you compress the outside air, any humidity in the air condenses as water. When you get water in your air tanks, there is danger of it getting into the lines to the wheels and freezing or causing other mischief.

It is a good practice every day to open the valves at the bottom of all the air tanks to spit out the water until there is just air coming out. Sometimes this is a petcock that takes a quarter turn, other times there is a cable you can reach and pull from the side of the truck, kind of like an overhead air horn cable.

I haven't heard of any reason to drain all the air when not running a vehicle for a while. I even worked on some Macks that would not stop the engine when turning the key off unless there is air pressure built up. The first time this got me was a surprise.

Apparently, the operator had shut down the engine and then gone underneath and left the air drain valve open on the truck that needed radio work. When I finished working on the truck, I discovered I had to go under the running truck, shut the petcock, and wait with the key off for the engine to stop.

So that story points both ways. Mack designed the truck to be shut down with pressure in the tanks, but the operator made a practice of draining them. Either way, make sure any water present spits all out when you open the do your pre-trip checks.
Awesome. So leave air in it while sitting, but drain intermittently to remove water! Got it!
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Old 07-05-2015, 12:14 AM   #5
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In days of old (60's) the trucks I drove needed to be drained daily before driving. Fire them up, wait for the compressor to cycle, drain 'em, always got water. This was before we even needed commercial driver's licenses in the area I worked.
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Old 07-05-2015, 05:49 AM   #6
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My old squadron had hand receipted a pair of 93x 5 tons from the Army Guard, we drained the tanks regularly- same on the LMTVs the wing had on hand receipt. Army Guard likes to keep their trucks drained when in storage.
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Old 07-05-2015, 03:46 PM   #7
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Quote:
Originally Posted by crazycal View Post
If your brake system doesn't have an air dryer, then yes, it is good to drain your system on a regular basis to release trapped water.
Just my 2 cent but I was thinking about automatic drains just like we use on high capacity air compressors at work? No electricity! it works off of a float and powered by the air system it serves just like a steam trap or condensate pump. I don't have the make and model in my head but will tomorrow when I get to one of my jobs with one installed. If you are interested they look like little chrome eggs. Drain in the top,condensate out the bottom. Have been very dependable for many years ( sorry i do new construction ) and only have a 1-year warranty. I have not been back to work on 50 of these installed in the last 18- years but I have been back to work on the solenoid valve (electric type ) and replace with the egg and have never been back for that issue.
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Old 07-05-2015, 07:44 PM   #8
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Quote:
Originally Posted by Jolly Roger View Post
Just my 2 cent but I was thinking about automatic drains just like we use on high capacity air compressors at work? No electricity! it works off of a float and powered by the air system it serves just like a steam trap or condensate pump. I don't have the make and model in my head but will tomorrow when I get to one of my jobs with one installed. If you are interested they look like little chrome eggs. Drain in the top,condensate out the bottom. Have been very dependable for many years ( sorry i do new construction ) and only have a 1-year warranty. I have not been back to work on 50 of these installed in the last 18- years but I have been back to work on the solenoid valve (electric type ) and replace with the egg and have never been back for that issue.

Not sure if those are for truck applications but this is what I was talking about.

https://www.google.com/search?q=air+...iw=959&bih=673
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