I have an original, all-metal heater control valve that was NOS when I installed it on my 1970 Mach 1 in 2007. I just had to replace it (thankfully I had a spare) due to a failed seal that allowed coolant to flow through it. Does anyone know if it's possible to rebuild or repair this type of valve? The all-metal versions are hard to find and I'd rather not throw it away if it can be repaired. FWIW I asked the guys at Classic Auto Air and they said it can't be done.