Change Your Water Impellers

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A 'vacuum pump' wrench.JPG

My NP 42 has two Cummins diesels. The water pump is mounted very closely in a corner of the engine case. It is almost impossible to unbolt the pump without scraping knuckles and cursing Cummins.
It is recommended that the pump impeller be changed annually. I waited almost two years for the first change because the job was such a pain in the butt. When I finally got around to it I discovered that both impellers had paddles hanging by a thread - about to break off and proceed into the engine. Do not put this job off!
I have discovered a tool that makes this job simple and much easier.
Aviation engines have the same problem with vacuum pumps mounted to the engine case in tight spots. They use a 7/16 wrench called (surprise!) a Vacuum pump wrench. The hardened handle is made in a long U shape so that the mechanic can reach around behind into the tiny space behind the pump where ordinary fingers and wrenches won't work.
Do a search for "vacuum pump wrench". I got mine from www.aircraftspruce.com They had two listed for about $20 - $25.
It is worth much more, especially if it saves your engine.
If I can figure out how I 'll try to attach two pictures.

Ted Shanks

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water impeller

Ted,
A couple of great photos.

My Cummins has a plate on the back (where your knuckles are) with three bolts so I guess I don't need one of those wrenches.

I am presuming that if I undo those three bolts and take the plate off the impeller will just come off the shaft, is that correct?

Henry

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