When I brake, one air gauge is leaking.and THE OTHER ONE ISNT!! NEED HELP ASAP

Well not surprised drivers don't know air brakes. But GARAGE in my world mean mechanic. OMG!!!!!!!!
I don't know what designation is for the right gauge please read what it says on the gauge.

 

Is the leak coming out of the gauge and you can hear it in the dash or is it leaking somewhere in the system that the gauge monitors?
How fast is air dropping?
Chock tires so truck well not MOVE.
Air up system
Release park brake
Let system air up the rest of the way up to 120
Shut off truck and everything that makes noise around it.
Put something on brake pedel that can hold it down.
Walk around and under truck and trailer were the brake system is and listen for leak.
Spray everything down with soapy water if you can.

 

My best guess is you have a pretty big brake leak somewhere.
When you step on the brake the air is leaking out and the the gauge drops and the low air warning light comes on.
Shut the truck off push in the yellow and red air buttons (with a trailer attached) then have someone step on the brake pedal and you go around the truck and trailer and listen for the leak.

 

Is one of your brake chambers leaking? Chalk wheels,. Release brakes,. Use a board to depress the brake pedal then walk around and listen for the leak. The other two posters beat me too it I ypet slow

 

I’m worried about op not knowing the basic air brake test. But as far as mechanic he may have in his panic taken it in to a car type shop that doesn’t know anything about airbrakes or trucks. So that is excusable.

 

I cannot stand seeing truckers say they are not provided knowledge about air braking. Right gauge? Eh I could guess secondary, that would fall first followed by Primary but it will be maybe a brake chamber or something else.

I don't know enough to attempt a opinion because the detail is lacking from OP.

God help this industry if it constantly fails to teach methodology and theory of air braking etc.

 

Brake Chamber or Brake line sir!
Rarely it will be a brake line to the brake chamber. You can change half the brake chamber, all of it or just the pancake if the brake chamber is in good condition. Just have to find which one is leaking as suggested in other posts. Not nearly as big a deal as it seems.

 

just a suggestion/question but why not push one button in at a time and know if it’s the tractor or trailer(use trolly)?

 

OP stated that he recieved no teaching from anyone regarding brake systems in 18 wheelers. So the buttons might as well be bright colored doodats that say lets go.