Brew, that has been addressed many cylinders ago. With the pedal play at its max, the cylinder still holds enough residual pressure to hold the inching cylinder engaged and in some circumstances enough pressure to hold fast on the brakes enough to stay midway on loading dock ramp until pressure bleeds off to roll free (90secs) and to relax the inching cylinder, at least that or longer. An eternity when an operator is trying to off load in street. The failure seems to be related to under seat temps. Going back through archive invoices, they seem the group around the warm months. Keeping the radiator core clean lenthens the useable lifespan only slightly. I have taken old ones apart and think I see some swelling of the rubber parts but without new parts to compare, hard to tell. Back to orig question, would silicon fluid improve performance? Rubin