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Fixing Dead Pool Pump Motor By Replacing Bearings | Century Centurion B1000 Commercial Motor Locked

After replacing all the seals and gaskets on the pump, the pool pump motor ended up also needing its bearings replaced because water had gotten past the multiple seals and into the bearing. The motor is a Century Centurion B1000. It was impossible to find out what size bearings were used. None of the pool companies knew, and I also contacted the manufacture, which led me to their local service center, who spent some time looking for documentation that had the bearing sizes, and they could not find it either. Finally, the bearings seized, the pump motor stopped, and we had to remove and take it apart to determine the bearing dimensions.


The front bearing is an NSK 6304DU (Replaced with a 6304-2RS) designed for a 20mm shaft -Buy on Amazon: or on McMaster:

The rear bearing is an NTN 6203LH (Replaced with a 6203-2RS) designed for a 17mm shaft - Buy on Amazon: or on McMaster:


Pulley/Gear/Bearing Puller:

Dremel Tool:

Cut Off Wheel for Dremel:

Dead Blow Hammer:

Flat head screwdriver:

1/4in nut driver:

The motor must be completely removed and disconnected from the pump and power. The impeller has to be taken off the shaft. There's a rubber ring around the shaft that is supposed to sling water away from the shaft. Remove that. Then there's a metal washer pressed in. Use a screwdriver to remove that by prying through the housing drain hole under the shaft. Behind that, you'll find another rubber ring. This is the last line of defense to keep water out of the motor housing. Remove that too. Then there's a screw that holds the bearing that must be loosened.

Mark the positions between the front, center, and back motor housings using a marker or tape to make sure that you can easily realign them when reassembling.

There are 4 extremely long screws on the back of the motor that holds it all together. Carefully unscrew those. Some may need to be worked back and forth a little due to corrosion.

The front of the motor housing was stuck to the bearing/shaft so I had to use the gear puller to remove it.

The bearing was completely shot and damaged. The size was barely readable. It was marked NSK 6304DU.

I tried to use the gear puller to remove it, but even after applying an enormous amount of torque using a 1/2in extension ratchet, it would not move.

Ultimately I had to remove the outer bearing race, and use a small abrasive cut off wheel to cut a slit in the bearing to be able to open it and remove it from the shaft. That's when I saw that the bearing had lightly stir welded itself to the shaft, thus explaining why the puller could not remove it.

Surprisingly the repair worked. The motor sounded just like new and we saved over $700. Great Success!




Our pool pump motor has 2 methods for electrical connection, push-on connections and screw terminals. Previous installers only ever used the push-on connection terminals. The problem with push on connectors is that the max current rating is only about 20-25 amps (for good quality connectors). A 220V 5HP pool pump motor is pulling 20-25A, therefore the current draw is at the max limit of the push on connectors. I say this from experience because the wiring has burned out twice from heat generated by resistance at the push on connectors.

At first glance, the screws for the screw-down terminals appear to be screws that hold down the metal terminal, not screws that can be used for electrical connection, but they are in fact screw terminals for electrical connection. Those screw terminals provide a much better electrical connection than push on connectors, so it's better to use the screw terminals with a crimp on ring terminal than to use the push on connector.


▶ Ring Terminals for 10-12 Gauge wire #10 screw -

Crimping Tool for best quality crimps -

AC/MC/Flex Squeeze Connector 1/2-Inch, screws into motor electrical box -


Fixing Dead Pool Pump Motor By Replacing Bearings | Century Centurion B1000 Commercial Motor

The products shown here were purchased by me with the intent to use. I did not receive any free items, and I am not being paid or compensated for this review.  The video and description may contain affiliate links. If you click on a link, I may receive a commission. Money earned helps to support my channel and bring you more informative videos about engineering, crafting, and DIY.


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