What should be done if one of the brass supply valves is leaking or shows signs of corrosion within the valve?

Over a period of years, the buffer valve, and possibly others, may begin to corrode within the brass valve body. As of November 2022, the buffer valve in new instruments comes with a PEEK chemical-resistant valve body. However, older instruments may show signs of internal corrosion, pitting, and leaking buffer, pulling this reagent in, and not sealing internally as it once did. The other supply valves (Water, EtOH78 and EtOH95) may also show signs of corrosion or contamination to a lesser degree and may also require cleaning or replacement.  To clean this part or to replace internal seals, follow TDF Service Procedure Solenoid Supply Valve Seat and Body Seal Replacement (TS017).  To change the entire valve body, follow the TDF Service Procedure Supply Valve Body & Piston Replacement (TS046).