air bleeding into intake

[those military guys rob]

just a question i have a few m923's and i just notice that one that gets used the most that when you put the parking brake on it bleeds air off into the air intake for a couple seconds then stops is this normal, the brakes work find and it builds and holds air great and i have walked around the truck and checked all the wheels and i hear no leaks.
thanks

 

[MarcM35A2]

I think that is normal. My truck does the same. To put the brake on, you have to release the air from the sprin brakes. And why should the truck wast the air when it can be used for the engine??? And the release valve opening is protected from water, dust and dirt, because it is inside the air intake.

 

[Suprman]

Yes its like a howling groan every time you park somewhere.

 

[those military guys rob]

Thank you guys for your responces, i figured it was fine but i thought i would ask thanks again.

 

[Hard Head]

I have a similar issue on my 923A2. When I apply the brake the primary tank drops 20 - 30 psi and I hear it in the air intake stack. I can bleed the primary tank to 90 psi in around 2 cycles of on off the brake sequences at engine idle. Not good. Any ideas why so much is air is lost to the intake or are you also seeing this kind of pressure drop? The CTIS controller is disconnected and one axle is missing the CTS valves.