Lots of luck getting a response from Comp ARF about anything regarding the Mig. I built one over a 2 year period (should have been MUCH shorter) and trying to get parts that were missing, or even just answers was near impossible. It was absolutely horrific service. It's like they want NOTHING to do with the Mig, unless they're taking your 10K for the kit. I know everyone says that they get great service from Comp ARF, and what a great company they are, and I've had other comp arf products where sales and after sales service was good, but the way they dealt with their most expensive kit and what was at one time supposedly the flagship of their line was repulsive. I will personally never spend another penny with Composite ARF. I wish I had a better answer for you, but truthfully, if it's been changed to air and it's working, I'd just leave it alone. Are your gear the new generation at least with the locking mechanisms in the gear cylinders? I can't imagine having to deal with the original system at all.
As for the valves, I believe they has the Hausel label on them, same as the pump, perhaps try dealing directly?