I disassembled the foot pump from the head to see why it is not working. It's 20+ years old, the one at the bottom, Mk II (or Mk 2) (Whale Gusher Galley Pump Mk 3 & Mk 2 exploded). The intake and outlet valves looked fine, the rubber diaphragm was a bit distorted but still pliable with no tears or holes. I adjusted the diaphragm and reassembled, but it's still not pumping.

A spares/rebuild kit consisting of rubber o-rings, valves and diaphragms is about $30 US, while a replacement Mk 3 from discounters is $100. I like saving money and don't mind the work, but I wonder if the rebuild will do the trick or if I should save the trouble and splurge on a new one.

Anyone used this repair kit? Any experience as to whether the Mk 3 is a drop in replacement and will hold up for another 20 years?