Air dryer pop off valve leaking

No picture posted. But yes, the purge valve can be replaced.

 

you need to get the kit. make sure there is no air in the system.

 

Most cases the valve spool gets gunked up and sticks.

 

Good thing it's failing now. You'll have a fresh one for the winter. That's when they usually fail.

Might as well change the desiccator cartridge in the dryer while you're at it.

 

Those things really shouldn’t go bad if the system is functioning efficient and kept clean. It’s always a good idea to spray some brake clean through them a few times a year. The dirt that sticks to them on the outside is just as bad as the oil from inside.
How many guys actually think to scrub them clean with dawn or degreaser when washing the truck or at least hit them with water out a garden hose to keep dirt and grease buildup at minimum? Kinda like washing out the brake dust from the drums and shoes, hardly ever done till replacement time.

 

stop throwing money at it and find the cause. does your compressor unload when it comes up to purge? pull off the compressor hose and find out.