hey post a pic of how you have it setup ..... if your using the bottom port for the vac and a dump that is you problem most likely because of poor vac transfer and slow dump cycle ( yes that is how they set it up from the factory, but i tryed it that way and had no luck with consistent cycling ). i wouldn`t mess with the rubber tapered seal at the top, bender have a small built in leak to help break and recycle the float rod and also you shouldn`t have any bubbles coming in from the bottom that just shows you have a leak.
2x6 leader WSE with AUF, hood,preheater
waterguy RO
leader 16 gal custom water jacketed canner
10 in short stack wes fab filter press
540 taps on tubing with vac & always adding
2- benders running 25" hg from GAST vac pumps
few stainless bulk tanks
1978 chevy 1 ton 4x4 dually
IH T340 dozer with 6-way blade