Hypro D503 Diaphragm Kit
Diaphragm Kit 9910-Kit1881 is used to rebuild to Hypro D503. Hypro recommends changing the diaphragms every 500 hours or three months. whichever comes first. If your oil has turned a milky color there is a good chance the diaphragms have ruptured.
Kit1881 has been superseded by AR43295.
This kit includes three replacement diaphragms (9910-620085) and six replacement valve O-rings (9910-840110).
When replacing the pump diaphragms follow all factory torque specifications. Replacement O-ring kit (9910-kit1984) and valve kit (9910-Kit1987) are available for a complete rebuild on the Hypro D503. New oil is required for diaphragm replacement. Replace with SAE 30 weight non-detergent or Hypro oil (2160-0038).