Q: How do I replace a torn diaphragm on a Flojet R4105343A and do I just change the diaphragm or other bits.
A: To replace the diaphragm you will need to remove the lower housing and cam.
There is a small slot in the lower housing where it meets the motor. You need to put a screw driver through the slot to undo the screw that holds the cam in place. You can then remove the complete housing, change the diaphragm and cam if required then reassemble.