Local agricultural dealers have cheap packs of BSF grease nipples. Or at least my one has. If your plungers are shrouded and the shrouds are full of grease, as the plungers move they are squidging grease around the place rather than the usual air/rusty water mix. Grease being higher viscosity than air/rusty water provides a hint of damping. Just a hint but better than none at all.
