m923a2 not airing up

[winterton1]

the last couple time a started the truck, it took a long time to air up. The last time it would not air up past about 25 and now not at all. I soaped everthing i could with soap but no luck. i replace the governor and did a complete service/rebuild on the air dryer. Still would not air past about 25 . .. i hooked up my compressor to the hands but still only got abot 30. I re-soaped everthing in sight and found a valve leaking on the passanger side tank closest to the air dryer. Could this one valve leaking stop the truck from airing up??? i know it sounds like a dumg ? but with all the air that should be going in i wouldnt think that would do it. Im going to get a new valve , but was just wondering...mike

 

[simp5782]

If both emergency gladhands are close i would start by Spray around the spring brake cans.

 

[winterton1]

If both emergency gladhands are close i would start by Spray around the spring brake cans.

I will give them a a soap spray.

 

[Coffey1]

Also check head gasket on compressor damn things blow out.

 

[simp5782]

Also check head gasket on compressor damn things blow out.

If the truck wont air up with shop air then it is an issue somewhere else. A check valve at the air dryer prevents back feeding to the compressor

 

[Coffey1]

Unless like all the check valve's I've seen shot to hell

 

[Swamp Donkey]

Make sure the purge valve on the bottom of the air dryer isn't stuck open.

 

[winterton1]

I replaced two leaking ball valves, rebuilt air dryer and put a new govenor in, but still no luck. when airing from shop i stll cant get past about 27psi and can now here air escaping the air filter intake stack. Any ideas??

 

[Coffey1]

Give a call 704-534-4486 Ken

 

[winterton1]

ken- do you have an NSN or napa # for the q2 valve in case thats the problem?

 

[simp5782]

Napa 229505x. Oreilly 229505c

 

[Coffey1]

 

[winterton1]

Thanks!

 

[winterton1]

i replaced the q2 and quick release valves for good measure along with all of the brake diaphragms. figured i might as well...a few were cracked but nothing to bad. i sill have air escaping the stack and truck wont air up even with the shop compressor. could it be the treadle valve...how would i test it?

 

[simp5782]

i replaced the q2 and quick release valves for good measure along with all of the brake diaphragms. figured i might as well...a few were cracked but nothing to bad. i sill have air escaping the stack and truck wont air up even with the shop compressor. could it be the treadle valve...how would i test it?

Close the primary tank valve on the wet tank under the truck. Air the truck up from a compressor. See if the secondary takes on air. If it does and the air is not coming from the stack we know its on the primary side. Repeat this test with the secondary valve closed if needed.

Or


On the frame. Behind the air box. Is a valve. Will have a big line or two from the front. One or two small air lines going into it. One big line from it will go up and over the frame. That is how you identify the valve

Remove each air line 1 at a time while the truck has air escaping from the stack. Then post a picture of which air line you removed had the air coming from it.


These are the vents. I can tell you where the issue is from these lines

 

[winterton1]

thanks

Close the primary tank valve on the wet tank under the truck. Air the truck up from a compressor. See if the secondary takes on air. If it does and the air is not coming from the stack we know its on the primary side. Repeat this test with the secondary valve closed if needed.

Or


On the frame. Behind the air box. Is a valve. Will have a big line or two from the front. One or two small air lines going into it. One big line from it will go up and over the frame. That is how you identify the valve

Remove each air line 1 at a time while the truck has air escaping from the stack. Then post a picture of which air line you removed had the air coming from it.


These are the vents. I can tell you where the issue is from these lines

...thanks ...i will check these thursday when im off.

 

[winterton1]

thanks

...thanks ...i will check these thursday when im off.

forgive my ignorance...what is the "air Box"...thanks again for the help!

 

[winterton1]

forgive my ignorance...what is the "air Box"...thanks again for the help!

I aired up the truck and both the wet tank and secondary tank charged with air. the primary tank guage onn the dash read 120 and no air was escaping from the stack. the secondary still read 0. i took a pic of the valve i thing you were describing on the drivers side frame. it does have a line that leads from it to the stack... is this the correct valve to check?

 

[simp5782]

I aired up the truck and both the wet tank and secondary tank charged with air. the primary tank guage onn the dash read 120 and no air was escaping from the stack. the secondary still read 0. i took a pic of the valve i thing you were describing on the drivers side frame. it does have a line that leads from it to the stack... is this the correct valve to check?

Yes. When you have the air escaping from the stack. Remove one line at a time till you find out which one has air coming out of it. And send me a pic of it and what direction on the truck it goes

Those two lines on the bottom going to the front of the truck. One goes to the Q2 valve. One goes to the lowest connection hose on the brake pedal valve in the engine bay

 

[74M35A2]

I aired up the truck and both the wet tank and secondary tank charged with air. the primary tank guage onn the dash read 120 and no air was escaping from the stack. the secondary still read 0. i took a pic of the valve i thing you were describing on the drivers side frame. it does have a line that leads from it to the stack... is this the correct valve to check?

It’s the black hose in your first pic.