I bought a Melling High Volume Oil Pump and shaft and the shaft keeps falling off every time I turn the motor upside down...the shaft falls off . The high volume shaft has a steel sleeve when the standard has plastic sleeve on the shaft. Would installing the intake and the distributor first be best then put the oil pump and and oil pan on last?

Pack the steel sleeve with a good wheel bearing grease. Insert shaft. Shaft will stay in when the engine is inverted. Grease will dissolve in oil after engine is run.

Ther should be something inside the female end, like an o-ring, or a plastig ring that snaps around the groove in your pump shaft and holds it on there. If it comes off, where does it go ? It can't go too far, it should be trapped between the block and pomp shaft, and when you flip the motor up, doesn't it drop back down ?

The sleeve and drive go around the pump shaft and is installed before the pump is mounted and the sleeve is large enough that it shouldn't fit through the main cap. Do you have the shaft upside down with the sleeve at the distributor end? If it is in correctly I wouldn't worry about it there isn't enough room for the drive to fall out completely and getting it to engage when the motor is turned back over is as easy as taking a long screwdriver and turning it until it falls into place.

This question pops up fairly often in my shop. The shaft with the metal sleeve pinned on is designed to slip over the drive on the oil pimp. Simple as that. When the engine is turned upright, the drive will fall into place on the pump and the dizzy will hold everything in place.

tom