Air Leak Woes

[zout]

I realize it vents - when shut down it vents off the tanks and its not within reason it can empty the tanks in less than an half hour once the engine is shut off an no longer building air. If the engine is running and you do a brake pressure cut out test and pump the brakes till your protection valve pops it will pass. If you shut down your engine and perform the test as well as the system self venting itself it will still do the same but only sooner.

The tm explains this thoroughly.

You stated during operation it vents - it only vents when shut down.

 

[brock]

I realize it vents - when shut down it vents off the tanks and its not within reason it can empty the tanks in less than an half hour once the engine is shut off an no longer building air. If the engine is running and you do a brake pressure cut out test and pump the brakes till your protection valve pops it will pass. If you shut down your engine and perform the test as well as the system self venting itself it will still do the same but only sooner.

The tm explains this thoroughly.

You stated during operation it vents - it only vents when shut down.

I have assurances from multiple sources that venting of the tanks when the truck is turned off is not normal. It should hold air pressure in both primary and secondary systems until I manually drain the tanks. Of course the systems aren't perfect and there will always be leaks, with that said I don't think its normal to lose all that air so quickly.

I will continue to troubleshoot while referencing the TM's and report my findings.

 

[plode]

I'm restarting going through the TM to try and figure this out.
TM 9-2320-272-23-1 WP-133

From what I've read so far, it's either one of the relay valves, or the treadle valve.
I'm going to start with checking the relay valves. Rather then following the TM and hooking up a pressure gauge to each one, I'm just going to disconnect the vent line and see if either is leaking. If they aren't, I'll move on to the treadle valve.

Echoing one of the OP's questions- is the treadle valve serviceable?

 

[quickfarms]

I greatly appreciate your heeded warning and do not take driving this truck lightly. I will be parking the truck until I get my license.

I picked up the truck on Friday and drove it around my neighborhood over the weekend, its definitely a beast to drive.

Thanks again.

They are a very easy truck to drive. I would not consider them to be a beast. But then again I was driving big trucks before there was a CDL requirement. I learned to float gears on a twin stick. This truck has an Allison and power steering.

The rule of thumb has been if the air leaks down during the day enough to trip the low air buzzer the problem needs to be fixed. In reality this translated to about 1 to 2 hours of having the truck shut off for loading, unloading or lunch.

Most all truck do leak some air. It is common for some air to bleed off over night.

 

[PureMayhem]

I would bet that it is leaking while the engine is running as well but you just can't hear it. I had a similar situation and it was the treadle valve. The lower half of the treadle valve is connected to the secondary air if I remember correctly. Try and listen down around the brake pedal when the engine is off. I used a stethoscope and could hear air movement when listening to the side of the treadle valve and the air lines to the pressure gauges.

 

[brock]

I would bet that it is leaking while the engine is running as well but you just can't hear it. I had a similar situation and it was the treadle valve. The lower half of the treadle valve is connected to the secondary air if I remember correctly. Try and listen down around the brake pedal when the engine is off. I used a stethoscope and could hear air movement when listening to the side of the treadle valve and the air lines to the pressure gauges.

Thanks. I will take a look at the treadle valve this weekend. The more I research the more I suspect the treadle valve. Im going to try a few drops of pneumatic oil to see if its just a sticky valve. I may just replace it with a new unit because it poses a safety concern.

 

[quickfarms]

Does the air vent or bleed off the same if the parking brake is applied or released?

 

[quickfarms]

I am currently prepping for my class B CDL test. Ill research the COLA test.

Thanks

Real men get a Class A, with endorsements. I have known quite a few people that originally got there Class B and later had to do it all over again to get the Class A. There is only one guy I know that has not wanted or needed a Class A after getting his Class B.

 

[plode]

Does the air vent or bleed off the same if the parking brake is applied or released?

Mine vents regardless of the position of the parking brake.

 

[brock]

Mine vents regardless of the position of the parking brake.

No difference when the parking brake is applied or released.

 

[brock]

Real men get a Class A, with endorsements. I have known quite a few people that originally got there Class B and later had to do it all over again to get the Class A. There is only one guy I know that has not wanted or needed a Class A after getting his Class B.

Well, soon you'll know two.

I do not and will not have a need for a Class A license.

 

[PureMayhem]

Thanks. I will take a look at the treadle valve this weekend. The more I research the more I suspect the treadle valve. Im going to try a few drops of pneumatic oil to see if its just a sticky valve. I may just replace it with a new unit because it poses a safety concern.

I bought a used treadle valve off another member and installed it and then took the opportunity to take the original treadle valve apart just to see how it works. It is definitely rebuildable. Look at TM 9-2320-272-24-3 chapter 4 -108. The rebuild kit identified there is NSN 2530-01-134-1834. There is also an O-ring - NSN 5330-00-074-2692 mentioned in 4-108.

 

[brock]

After performing some troubleshooting this weekend I was able to isolate the issue is with the treadle valve. When the system is pressurized there is a steady flow of air coming through the secondary side of the valve and exhausting through the line going straight to the stack. I will order a new replacement and report my findings.

Thank you all for the great info.

 

[brock]

Couple of Beauty shots for you guys!!

 

[quickfarms]

Well, soon you'll know two.

I do not and will not have a need for a Class A license.

If you are only going to get a Class B you should remove the pintle hook and trailer air fittings from the truck.

With them still on the truck an officer can write you a ticket for driving out of class because the truck is set up to tow a trailer over 10,000 lbs.

It is simply how the officer interprets the vehicle code.

This is a real issue with certain agencies.

 

[Artisan]

If you are only going to get a Class B you should remove the pintle hook and trailer air fittings from the truck.

With them still on the truck an officer can write you a ticket for driving out of class because the truck is set up to tow a trailer over 10,000 lbs.

It is simply how the officer interprets the vehicle code.

This is a real issue with certain agencies.

Are you sure????????????????????

So your saying a Class B can NOT drive a Semi bobtail ?

 

[Artisan]

brock

Here is where you get matching paint 383 green plus

rapcoparts.com

 

[Artisan]

If you are only going to get a Class B you should remove the pintle hook and trailer air fittings from the truck.

With them still on the truck an officer can write you a ticket for driving out of class because the truck is set up to tow a trailer over 10,000 lbs.

It is simply how the officer interprets the vehicle code.

This is a real issue with certain agencies.

Not True.........


I just called my teacher at DOOTSON truck driving schools and I posed
the same basic question and no, you only need a Class B to drive a 5 Ton.

See Commercial book inside the front page;
CALIFORNIA DRIVER LICENSE CLASSES - VALID AS OF APRIL 1, 2012
(With a commercial Class B)

Additionally he told me DOOTSON sends guys to the DMV to take their Class B
test in there SEMI's . If the driver does not want a passenger endorsement
they can take the test for a class B "ONLY" in a full blown semi truck WITH
a 5th Wheel and pintle hitch and Gladhands and and and...Class B ONLY!


If " Certain Agencies " care to tangle w/ me and if they are wrong and if
I ask "DID THE ACADEMY OR ANY OTHER SCHOOL TEACH YOU TO DO THIS?" and the officer
says NO then obviously he was acting on his own accords and after
I get my case dismissed I for sure would launch an IA investigation.

Do NOT be afraid of the police, you have RIGHTS. Know them and do
NOT listen to guys* on the internet. Verify for yourself.

*That includes moi! Verify for yourself

 

[brock]

Not True.........


I just called my teacher at DOOTSON truck driving schools and I posed
the same basic question and no, you only need a Class B to drive a 5 Ton.

See Commercial book inside the front page;
CALIFORNIA DRIVER LICENSE CLASSES - VALID AS OF APRIL 1, 2012
(With a commercial Class B)

Additionally he told me DOOTSON sends guys to the DMV to take their Class B
test in there SEMI's . If the driver does not want a passenger endorsement
they can take the test for a class B "ONLY" in a full blown semi truck WITH
a 5th Wheel and pintle hitch and Gladhands and and and...Class B ONLY!


If " Certain Agencies " care to tangle w/ me and if they are wrong and if
I ask "DID THE ACADEMY OR ANY OTHER SCHOOL TEACH YOU TO DO THIS?" and the officer
says NO then obviously he was acting on his own accords and after
I get my case dismissed I for sure would launch an IA investigation.

Do NOT be afraid of the police, you have RIGHTS. Know them and do
NOT listen to guys* on the internet. Verify for yourself.

*That includes moi! Verify for yourself

Thank you @Artisan.

I thought that sounded like a bit of a stretch.

 

[silverstate55]

Hate to rain on the parade, but quickfarms is correct. I asked a couple of CHP commercial enforcement officers this last year, and they confirmed what quickfarms said. Nevada Highway Patrol & Nevada DMV also concur with this, and the NV DMV won't even let you take a Class B driving test with a semi-tractor.

Pretty much their views are that if the vehicle is equipped/capable of hauling a semitrailer over 10K-lbs (whether it is or not), then you need a Class A or appropriate CDL to cover it...a Class-B won't cut it.

Just words to the wise.