ac valve question
 

Anyone replace the air conditioner schrader valves? My high side is leaking.

Yes, all the time. I run an automotive AC shop; the valve cores and compressor front seal are 90% of the leaks I find.
If they are more than 2 years old or have been serviced more than twice I change them. They're cheap.
I fully recover the charge before changing. The "change while system charged" tools are difficult to use and often lead to complete loss of refrigerant charge when things go wrong.
I only install SanTech brand A/C cores. When cores I installed leak I have PISSED OFF customers. SanTechs don't leak...
Do not use cores originally intended for tires. Different materials and pressure levels make AC cores different.
Butter the cores up with silicone grease before install. NEVER use 134a refrigerant oil as PAG oil is extremely hygroscopic and will corrode up aluminum fittings quickly.
R12 mineral oil is fine for O-rings and cores. Sili grease is better and works fine with both 134a and R12
Always install caps to keep moisture from cores (I butter up the caps with sili grease as well.