I have just finished restoring a Standard double-valve player action.
All components have been replaced. The secondary valves, both seats,
tested completely tight with the pouch board down at 5 inches vacuum.

It will hold that vacuum with input nipples sealed off as I set it
upright. However, after releasing the vacuum and attaching the primary
chest, the secondary valves will not re-seat once vacuum is re-applied
with stack in upright position.

I have adjusted the valve buttons so as not to touch the pouch but this
has not solved the problem. The gaskets have been replaced. What am
I missing? This is not my first rebuild. I have successfully restored
Shultz, Simplex, Baldwin, and other stacks in years past but it has
been a while since I have tackled a Standard.

I'm at my wits end; any suggestions appreciated.

Thanks,
Allen Scott