Tractor Protection Valve Leaking Air

[Groman]

I'm dealing with my tractor protection valve leaking air. The brakes work okay when it's being driven, but it is consistently losing air pressure. When the brake pedal is pushed down, you can hear air escaping along with seeing the gauge going down.

 

[Wildlife]

What type of tractor?

 

[ms&r]

Sometime in cold weather they can have ice develop inside and won't allow check valves to seat. I have put my fingers over the hole where you hear the air escaping and work the air valve and that will cause the ball inside to seat.