It is not too unusual for some leakage to occur from various places under the upper end of the pressure limits. To repair, simply tighten the screw which holds the inner diaphragm boss to the upper diaphragm boss. To access this screw, you will need to remove the 12 screws and 10 nuts which hold the ring down around the outer perimeter of the diaphragm. Then, you can lift the handle assembly and diaphragm up an out of the pump. On the underside, inside the relaxed diaphragm, find the ¼”-20 stainless steel screw/bolt which needs to be tightened in order to better seal against the passage of syrup through the top mount of the diaphragm. This screw needs to be very tight. Be sure to use an appropriately sized screwdriver in order to apply sufficient torque without damaging the screw.