Shutoff Valve Rebuild and sanitation

[PBrianG]

On my home kegerator I have 12 of the Micromatic straight shutoff valves 7419-1 (6 kegs spilt into 2 circuits: 6 patio taps and 6 basement taps). I use the valves to shut off patio circuits to protect from marauding teens and to switch flow to basement bar. I am deligent about cleaning by recirculating line cleaner and using chemical sanitatizers such as star-San and cycling the valves while cleaning. However I had a persistent infection and have traced to my valves. The web page indicates the Derlin seal is autoclave safe, so I tried steam sterilization in a pressure cooker at 240F. The valve is ruined!
1. Are these valves rebuildable? If so, how? Replacement parts?
2. How to properly sanitize or sterilize?
The valves are $28 each, so replace on a regular basis is out of the question.

I have emailed this same question several times over the last year and never got a response.

thanks

[DCullender]

Do you know what pressure you were running? From what I've read, they normally run around 15 psi.