What happens to these pumps is a seal inside is glued in place with clear epoxy. That glue joint fails over time. You need two pumps to make one good one because it's nearly impossible to remove the outer seal without ruining it. With 2 pumps you can use the inner seal out of the other one to replace the outer seal. I've been going to try re-gluing the seal with JB Weld but so far my current pump is still working. I actually just had an idea. With the pump removed, you could blow compressed air into the weep hole and blow the outer seal out without damaging it perhaps. Once the outer seal is out you remove the snap ring and the whole assembly comes apart. You'll likely then see the failed glue joint.