A wise maintenance technician once said, “There are two types of pumps—those that leak and those that are going to leak.”
Leakage is a common problem in all pump types. A few simple fixes can ensure the fluid stays in an AODD pump. First, pumps, especially plastic pumps, must be torqued to the manufacturer’s recommended rating. Materials relax over time—often referred to as cold flowing—which can cause sealing surfaces to loosen and create leak paths. Refer to the pump manual for torque values, and follow the bolting patterns to reduce the threat of leakage.
Reuse of polytetrafluoroethylene (PTFE) O-rings is another cause of leakage at sealing surfaces. A downfall of PTFE is resilience. Once a PTFE O-ring has been compressed, it is not capable of regenerating its original shape. Replace all pump PTFE O-rings when servicing an AODD pump.
After properly torquing the pump according to manufacturer recommendations and ensuring all sealing O-rings have been replaced after service, the AODD pump should be leak-free. Save significant rebuild time later on by ensuring the PTFE O-rings are replaced when the pump is rebuilt.
Credit by Michael Sandlin
https://www.pumpsandsystems.com/pumps/october-2016-5-minute-fix-troubleshoot-diaphragm-pump