Shouldn't have much metal to metal contact inside a pump, so I take Hill's advice and use silicon grease on the o-rings (and a very-very lite film on the tubes.Doesn't HAVE to be the stuff Hill sells, so long s it is silicon grease without any petroleum productshttps://www.pyramydair.com/product/hill-hand-pump-nlgi-2-silicone-grease-40g?a=3888http://www.straightshooters.com/silicone-grease.html