In Reply to: Re: NAA lift won't move posted by Kevin on April 26, 2017 at 20:40:07:
Well, I have the back-pressure valve out. Was re-re-reading some of Zane's posts and ran across a causal reference to testing the back-pressure valve. I read somewhere that it should break open at 45 psi. There's a gaping hole from the cylinder-o-ring-contact side to the tube. See image (link).
Is there any way to refurbish the valve? I banged it around and eventually got the valve to move freely. Reinstalled, wrangled the greasy lift cover gasket into place (again) and basically got the same behavior. This time I observed more carefully. If I cover the outlet of the back-pressure valve with my finger, the lift goes up, no matter how high the control lever is set. If I then release the outlet, the lift drifts down, seemingly to the position of the control lever, where it stays and feels firm as I push on it with my hand.
When the back-pressure valve is open, it pushes out toward the acorn nut. Before, it was frozen in that open position and I could see it without taking anything apart. Now, the valve appears not to be in that stuck-open position when I remove the acorn nut. So it's a different degree of failure. Can I "fix" this with a spring under the acorn nut?