Sorry to see you are not getting great response from CVR. This afternoon I decided to do a little more investigating on this, since the only time I'd ever tried to take the pump apart was on the side of the road during Drag Week in 2015. I have a new pump here on the shelf so I took a look this afternoon. First, there are four screws holding the electric motor in place. I took those out and started pulling the case off the motor, but I only had to pull it apart 1/8" or so to see that I was into disassembly of the motor windings and brushes and so forth with this approach, so I just put it back together. Then there are four screws that look like they would crack the case in half and expose the gasket. These are the four screws I was talking about in my earlier post. Just on the off chance that the pump I already tried this on was stuck or something, I took those four screws out, but nothing came apart.
I thought that maybe it wouldn't come apart because the case halves were pressed together, or else that the impeller was on the other side of the case, and keeping it from being pulled apart. I looked through the inlet fitting opening and after rotating the impeller a couple times I saw a set screw in there. It would have been really difficult to get at, though, and it appeared that it was held in place by Loctite, so I didn't even try to unscrew it.
While I was mulling this over, it finally dawned on me that maybe the screws that held the motor together also went into the other side of the aluminum case (Duh - slaps forehead...). Sure enough, two of the four motor screws were longer, and hold the motor to both sides of the aluminum case. Here's a couple of pictures of the case, which came right apart when I pulled those two motor screws. Also a picture of the impeller side, showing the set screw, which would now be easily accessible:
My guess is that there is a shaft seal behind that impeller, and that is what is leaking on Mike's pump.
