Hello, I am trying to troubleshoot a leak in one of the pump heads. The leak was very obvious, with solvent pouring from the top of the pump head. After opening it, I found that the outlet check valve at the top had a tiny crack in the plastic top part. A quick test of swapping that check valve to another pump head confirmed that it was indeed the origin of the leak. I therefore ordered a replacement check valve (5067-6642), and replaced it myself, not tightening it too tightly as recommended.
Upon restarting the pump, the top part was now fine, but the pump head started leaking heavily from the bottom. Upon opening it, I found that the inlet check valve was now also cracked, very similarly to what I had observed for the outlet one. I am about to order another replacement part 5067-6642, however I am very surprised that the two check valves on the same pump head would crack at the same time randomly, and I am concerned that this sudden cracking is due to another cause that I have not identified. Would anyone have recommendation on what could be the source of the problem?