As you may have read in my sandpoint well post, I have a shallow well pump that supplies water to my underground sprinkler system and some outdoor hoses. For several years this Mastercraft ¾ hp pump has done well for this application. At some point, the well lost prime though and the pump ran dry for a number of hours. The pump wouldn’t prime afterwards. I decided to open it up and see what the problem was.
When I took it apart to see if I could see any problems inside, I found that the plastic jet housing had deformed from the heat. Not wanting to just throw it out, I decided to rebuild it.
Since I had the pump apart, and I wasn’t sure if the mechanical shaft seal was damaged, I decided to take the impeller off to get a look underneath. Holding the shaft still at the fan end of the motor, and trying to turn the plastic impeller didn’t work for me. I’m sure there is a trick to this, but I couldn’t seem to get enough grip on the impeller with the tools I had on hand, and even when I did get a good grip on it, it seemed that I might end up damaging the shaft where I was holding it at the other end (fan end). Not being the type that gives up easily, I took the Dremel and carbide burr to the plastic impeller to gain the upper hand.
To remove the fan so that it can be reused, pry it off gently using something like a putty knife to spread out the force.
The following picture shows the impeller plastic all broken away, and only the brass impeller nut remaining. At this point, I was able to put a wrench on it and it broke free. There must be some Loctite on there from the factory.
After getting the impeller nut off, the mechanical shaft seal pried off with minimal effort.
Now the pump seal plate will slide off too.
The following picture shows the pump completely disassembled, and the 4 main parts that I ordered for replacement alongside their original, well used parts. When I started looking for parts for this pump, I started with Canadian Tire, but ended up finding out that Bur Cam Pumps and Water Systems seemed to be the Canadian supplier of these pumps and their associated maintenance parts. For the parts that I ordered, which were mainly plastic parts, I would have expected to the cost to be much lower than it was. The 4 main parts that I ordered ended up costing about 75% of the price of a new pump if you can find one on a good sale.
Reverse the disassembly steps. The pump seal plate goes on first. The ceramic insert is a key part of the mechanical shaft seal (the white part around the shaft). Handle it carefully.
The new mechanical seal is in place.
Screw the impeller onto the pump shaft. The new impeller had an improved plastic nut molded into the center which I used to tighten the impeller onto the shaft.
The jet pump venturi and diffuser assembly fits into the stainless steel body. The body bolts onto the motor flange.
Ready for reinstall. I ended up putting this pump back into service and it has run for several years now without any issue.