From my reading, the Ranco valve can only be rebuilt if the thermostat bulb and tubing is not damaged.
I looked into getting two I have rebuilt and the tubing was cracked on both releasing whatever is suppose to be in them.
At least as of 2 years ago.
Chip
'Rusto-Mod'
'51 Chevy 3600 5 window | C4 Corvette front/rear suspension & drivetrain | everything else looks old and stock
'92 GMC Sonoma GT #15 of 806
'91 GMC Sonoma GT Extended cab 1 of 1
Trucks, Trucks.....and more Trucks | 
