Snorkel air leak fixed

[FredRydr]

I have a Snorkel that was no longer drawing much ink, so I replaced the section seal, the barrel o-ring and a sac that looked recent. The seal and the o-ring looked original, despite the seller claiming the pen was "restored" (just by replacing the sac!). When I reassembled and lubed, the pen could hardly push out a bubble or draw a drop. My new sac was not at fault. Silicon grease was in place on the section/snorkel seal and the o-ring, but the barrel was not airtight. I removed the knob, applied a lick of grease on the top square part of the tube and replaced the knob. Now the pneumatic filler works. I wonder if part of servicing Sheaffer used to apply something to that area of the tube.