I have a Monarch MJC-50 shallow well jet pump (1/2 hp) and I want to tear the pump portion down to clean, inspect, and rebuild as it isn't delivering the pressure it used to (and I have ruled out all other causes).

I am unable to get the pump housing/casing to come apart from the motor, and I am reluctant to use more force.

The manual doesn't help, as it simply says "remove casing" :) I am basically stuck on the 2nd part of step 5. Do I just need to use more force?

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Here is the diagram of the pump. I can't seem to get piece #1 away from the motor portion.

MJC-50 Pump

  • 1
    A sledge hammer with two pry bars worked best for me. After I got it off, I noticed that the housing was cracked in several places and the repair kit I ordered didn't have any JB Weld in it so now I will try to use some of that stuff you see on TV that can put a alum. boat back together. Looks like just what the doctor ordered. May 12, 2021 at 21:24

1 Answer 1


I figured it out.

It turns out that part 16 (gasket) and 17 (cast-iron seal plate) (which to me, looked like part of the casing (part 1) came apart to allow the casing to slide off. I didn't realize they were separate from the casing as they were flush with it and painted the same blue color all over. The two pieces popped apart fairly effortlessly at the gasket.

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