Trailer air

Lol, much easier over the phone. Let Us know, probably a chamber.

 

He's saying you need to isolate the tractor from trailer and vice versa.

Red knob pulled and yellow pushed will show if problem is on the tractor.

Red knob pushed and yellow pulled with hand brake pulled down will be trailer..

No need to pull air lines to trailer.

Just push both knobs in and hold the brake pedal down and crawl under truck and trailer and check brake cans for air leaks.

There's a other trick too but I'm out of time

 

If your checking for broken springs in your maxi pots? Tap the pots on both Truck and Trailer with a light hammer, you can hear the spring bouncing inside the pot, That will be the one that is broken or remove the rubber plug on the end of the pot and look inside may need a flashlight.

 

I'm glad I didn't say it because it was wrong for his problem.
I was thinking when you have a rubber leaking on the park brake side of the can. Pinching of air lines until the leak stops