Rebuild kit on its way for my pump, including piston o-ring. Does it need a little lubrication when I put it all back together? If so, what sort?

I think it’s supposed to be silicon oil, so use that, if you’ve got it.

Perfect. I’ve got a little pot of that for the pivot on my motorbike visor.

my pump was being a dick and jamming under pressure. GT85 has sorted it nicely.

Silicon spray on my aged joe blow.
I thought gt85 could corrode so have avoided it. Time will tell Josh 🙂