I have an ornamental style garden water pump that I am looking for an alternative to the leather piston seal.   I bought the pump some thirty years and it worked for many of those years faultlessly.  Eventually the leather seal needed replacing to the point of needing to yearly, sometimes twice in a year.  Cheap, ~£2 through to ~£20 seals that perform, or not, just the same.

What I am looking for is an alternative to the leather seal that will last, Any ideas?  Or, maybe, redesign the piston with a modern seal?  The leather seal copes with the cylinder corrosion well enough, what about a modern synthetic seal?

The pump sits over a 150 gallon tank of harvested rain water.  Another hose pipe ban has just been introduced so I really want to get the pump working reliably.  Climate change (?) is making this more important.

Over to you guys.