I've got an old and leaking Taco 545-1 zone valve. It should be replaced with a newer model but I'd dearly like to just fix what's there for now. I'm writing to ask if anyone might know a source for older parts like this. I am wanting the whole assembly. I checked with Taco, but they just told me what to use to replace the old thing. I'll probably have to do it. If so, I'll be back to discover how to drain a heating system properly. The system is from 1984 so it's not too too old. The zone valve is the first thing that ever failed.