I took the suction foot assembly apart via rod, pliers, and hammer.
Came apart easier than anticipated, and of course, whatever
was inside for a check valve disc went flying, never to be seen again.
I turned a tin aluminum disc on the lathe, and loosely assembled
everything. Disc works great to keep air flow (gas) in the correct direction,
but sometimes, if I suck hard enough, also blocks flow from the
"running" direction. Wish I knew what the original looked like,
or better yet, "find it!"
I thought I had the screen pretty clean from soaking and wire brushing,
but when I "popped" it out, I could hardly see light thru it, so made
a new one. Also plenty of crud remained in the check valve housing,
even after all that boiling out with WD40.
Thanks.