Why does everyones deuce leak air pressure?

[Shawn MacAnanny]

Ive watched many videos of cold start ups etc, and everyone has an air buzzer going off including my own when i start it up, its down to 30psi or so by morning. My question is WHY?! I know air leaks, its an old truck but where are these slight leaks commonly at? Is it from the air pack? The glad hand valves? The tank drain petcocks? Windsheild knob? Axle lock? It drives me crazy. None of my other trucks every dropped that much air pressure over night. Even in a few hours of sitting it will leak enough air to trigger the buzzer. Am i really going to have to go across every single air connection with a bottle of soapy water?

Does anyone have a deuce that doesnt leak any air?

 

[swbradley1]

I'm sure there are a few out there that don't run. They probably don't leak air.

 

[gimpyrobb]

While some "may" leak, you are supposed to drain the air tanks to purge them of water when you park it.

 

[DieselBob]

I know air leaks, its an old truck but where are these slight leaks commonly at? Is it from the air pack? The glad hand valves? The tank drain petcocks? Windsheild knob? Axle lock?

Yes

 

[RedbeardTheZombieHunter]

Note to self: Pick up a spray bottle and a bottle of Dawn dish soap.

 

[swbradley1]

And wash the windshields.

 

[Recovry4x4]

Ive watched many videos of cold start ups etc, and everyone has an air buzzer going off including my own when i start it up, its down to 30psi or so by morning. My question is WHY?! I know air leaks, its an old truck but where are these slight leaks commonly at? Is it from the air pack? The glad hand valves? The tank drain petcocks? Windsheild knob? Axle lock? It drives me crazy. None of my other trucks every dropped that much air pressure over night. Even in a few hours of sitting it will leak enough air to trigger the buzzer. Am i really going to have to go across every single air connection with a bottle of soapy water?

Does anyone have a deuce that doesnt leak any air?

Nature of the beast I suppose. My cargo will hold air a few days, my wrecker only a few minutes.

 

[doghead]

Just pour some Bars Stop Leak into the air intake.

 

[Heavysteven]

Yeah, I know right always air leaks. I am using soft set 5 to help reduce the leaks.

 

[Heavysteven]

Just pour some Bars Stop Leak into the air intake.

No issue with this product and the airpack or pressure relief valve?

 

[Shawn MacAnanny]

Haha air leaks to me are a serious problem, for DOT pre trip if your tanks leak more than 3 psi while standing on brakes for 1 minute with truck off it fails. i guess if its normal the it is what it is.

Yeah stop leak sounds like a good idea. I was able to port and polish my intake, and turbo by holding the high idle out and just dumping sand into the intake, it'd probably work about the same

 

[Shawn MacAnanny]

No issue with this product and the airpack or pressure relief valve?

Well it would have to go in the compressor and would never make it down the lines. compressors and anything liquid are very bad. I would never imagine that was a serious sugestion. It would also stick every needle valve in the system.

 

[saddamsnightmare]

February 20th, 2012.

Shawn McAneny:

If the air compressor makes up the leakage, you're good, don't worry about it! The truck was buildt with 1948 technology, so yes, the system is never going to be airtight unless you rebuild and replace everything in it.... Then when you start it up after the rebuild, it's gonna leak air. There isn't a piece of equipment man ever built that uses air that isn't gonna leak it somewhere sometime...it's the nature of the beast. The good news...God's making more then your truck is leaking, so you're golden.....

 

[Shawn MacAnanny]

Haha yeah i know the compressor does make it up but its just more moisture in the lines, wear on parts. I dunno i deal with chemical injection points of the worst chemicals in existence. It's my job to make things NOT leak so there is absoultely no reason i cant stop this from leaking. If it was a hydraluic leak you guys would want to fix it.

 

[sandcobra164]

Mine seems to leak out of the aircompressor via the unloader on the firewall. When the air pressure drops to about 90, the unloader calls for air and it all bleeds on out from there. I'm not sure where the first 30 psi of air is leaking, I just drain the tanks when I park since the whole system is antiquated and doesn't even have an air dryer in sight.

Some may think it's a design flaw, The Army encourages running the truck at idle for "At Least" 5 minutes before hitting the road and of course idle for "At Least" 5 minutes coming off the road before shutdown. It'll easily build air at idle within those first 5 minutes, maybe they are on to something.

 

[Shawn MacAnanny]

i would absolutely agree with the idling for a few minutes before shutting down as these are only oil cooled turbos and can littleraly bake the oil in them if not properly cooled. Ive ran many turbo timers on oil cooled turbo cars ive had, its very important. most deisel turbos are coolant cooled nowadays so it doesnt matter.

you are supposed to drain the entire tank? I just drain the moister for a few seconds, i would think that leavin them open to atmosphere, would leave a much large potential for internal condensation since there was no pressure inside and would constantly supply oxygen for corrosion.

 

[dozer1]

At least they are a pretty basic air system. Comparing it to a big rig with its miles and miles of air line and many more valves, ect. If you go around with that soapy water you will find some I am sure. Fix and reduce leakage. You might wind up with the most airtight deuce around. There may not actually be that many leaks. It doesn't take that much to bleed down the air overnight. Big rigs have a lot more reserve too if I am not mistaken.

 

[emr]

Yes u are supposed to drain em down, since 1950 this has been working Im sure others have better ways, But for me when something works that long, it works...

 

[Shawn MacAnanny]

Yeah some trucks have 4 20 gallon tanks or larger if running a pressurized tanker, and trailers usually have dual 20s i believe. My 2006 international straight truck has 2 20s and can sit for a week and not lose any air. I would say the deuce has dual 10 gallons or so, i could be wrong though. i guess if its fine for all of your then its ok for me, i just dont think that the system has to leak.

 

[F18hornetM]

Ive worked on air brake trucks for 30 years and its rare to find one that will not set the alarm off over night. Yes there are a few that will hold over night, but its rare. You are right about the 3lbs leak in one minute with foot on brake, however I challenge someone to show me 3 lbs on an air pressure gauge in any commercial truck. Most DOT inspections check cut in/cut out pressure and an "applied" leakage. So if your truck leaks down over night, but works fine otheriwse, I wouldnt sweat it.

Never seen a commercial truck turbo that wasnt oil cooled, have not seen one yet coolant cooled.
I drove the m35a2. M813 and M923 for 4 years in the Marines, we NEVER let them idle before shut down. But having said that, I am very particular with mine, and any engine that comes off the street or out of the field cranked up should idle for a few minutes to cool down, a diesel cools down very quickly. So i just idle up my long drive way! Or Idle tractor around before shutting down, a little common sense