5-Cyl Vacuum Pump "Clack"

[Frederick Smith]

I did take one apart, just to see what made it tick/clack and found it
almost impossible to re-assemble. There are a few valve type things
inside along with a flat disc type steel diaphragm. From what I could
surmise is that oil accumulates on the "wrong side" of the diaphragm,
causing a hydro lock of sorts. This prevents the rod from deflecting
the diaphragm as it should..it bounces off instead. Clacking as it
rebounds repeatedly. 

Reassembly requires a press, to compress the coverplate against the
spring tension in order to reinstall the screws. I finaly got it
back together by using my drillpress to compress the cover. The
one I took apart was an extra one I had laying around.........I have
no idea if it would work/leak after the operation.

Smitty