mine does same. I replaced the caps this year and leaking was gone for a couple months, but now is leaking again. the plastic caps don't fit right. if their was a metal cap available I think it would fix our issue.
Blue, for what it's worth. I did a little reading and found a forum that mentioned that if the piston is to far out on the stroke, the initial push causes a flood to the reservoir. I toyed with mine a bit and so far no more leak
