Is anyone on the MMD expert in Simplex restorations?  I am in the
process of restoring my third Simplex, and am experiencing a problem
with the unit pneumatics that I have not had before.

I am at the stage of testing the valves at the lower seat, using a
test block received from PPCo many years ago.  On about 18 of the 88
pneumatics, the pouch rises and lifts the valve off the seat when I
suck on the supply tube (I'm not using the foot pump that came with the
block).  This means that outside air is getting under the pouch
somehow, but how?  I'm hoping not to have to tear each one completely
apart again.  The harder I suck, the higher the valve rises.

A few notes:

1)   Whatever they sealed the pouches with originally had begun to
peel off.  I scraped the peelings off and resealed each pouch and the
control channel with Phenoseal.

2)  I followed Art Reblitz's recommendation of hinging the pneumatics
(which originally had no hinges), which meant sanding off some of the
sealer where the hinge would go.  I used Phenoseal on the remaining
area inside the pneumatic between the hinge and the air hole (but not
up into it).

3)  I overlapped the pneumatic cloth on the side rather than on the
mounting end, eliminating the ridge which could cause leaks.

4)  I did not add any sealer above the pouch or in the valve well,
but I do not see how that could cause this problem.

5)  I replaced the gasket on my tester.  The tester has a fairly large
bleed for the control inlet, so I'm assuming I must have a good sized
leak.

I'm hoping to find something as simple as pneumatic cloth not glued
tight around the control channel, or a loose gasket at that point.
Since that does not seem to be the problem, I am planning to slice
the pneumatic cloth on one unit and use gobs of Phenoseal on the under
surface including hinge, and up into the air hole.  Any suggestions
will be appreciated!

Bill Maxim