In response to Dr. Dave Lunt's problem of no suction at the (Ampico)
tracker bar, the problem could be in the universal vent block, or the
tubing wrongly routed from the vent block to #10 nipple on the top
of the pump.  (See the Ampico service manual to locate these.)

First test the pump itself: while the pump is running, remove the hose
from nipple #10 on top of the pump and apply suction to it.  Also close
#10 off tightly and test.  This will test the pouch valve inside the
pump, which should allow vacuum to transfer to the large nipples, #1,
on each end of the pump.

If the pump functions with these tests, and delivers vacuum to the
pneumatic stack, the problem might be in the switch primary valve
(Fig. C) or any number of connections leading to it, including the
repeat switch, transmission port, etc.  Leaking gaskets or something
wrongly tubed is most likely the cause.

The best way to resolve the problem is start at the source and work
backward checking each component for leaks or wrong connections.

Bruce Clark