I got a chance to test the pitot/static system today and came up with the following results. It seems both problems are most likely related as the pitot systems ties the airspeed indicator, Vario, and Director together.

The pitot system did indeed have two leaks. The first and largest is inside the Cambridge MKIV Vario itself. The second smaller leak is inside the MKIV Speed Director. If I clamp off these two pitot connections just outside of the units, the airspeed indicator will hold an almost constant airspeed(a very slow leak of one knot or so in ten minutes). If I clamp off one unit at a time, the Director leak will drop the airspeed at about 10 kts/minute, and the Vario will drop the airspeed almost instantaneously. Since these are quite old and aren't service by Cambridge anymore I decided why not crack the cases and see what I can find. Both units have internal tubing from the case ports to what appear to be pressure transducers. The tubing looks to be in good shape and well sealed. Does anyone know if these sensors are some sort of calibrated leak/flow type of pressure sensor or should they be sealed with no leaks? Would it make a difference if the electrical power was on or off on the units?

If I can't get these units to seal the pitot system better it looks like a new vario will be more urgent than I had planned. I would still love to use these units for now if anyone has any further suggestions. Until then it looks like isolating the airspeed indicator and using the mechanical vario is my only option.