1. Remove the terminal connection cover
Loosen the terminal connection cover’s two screws with a flat-head screwdriver and remove the terminal connection cover. Check connections on terminal board. Test the electrical-line leads with an ammeter/voltmeter while supplying electric power; disconnect power before proceeding.
2. Mark the end-bell/stator alignment
Using a marking pen or masking tape, mark the position of both end bells for proper alignment with the stator.
3. Remove through bolts
Remove the four through bolts using the appropriately sized socket wrench or nut driver; bolt heads will vary from 1/4- to 5/16-inches.
4. Remove the REAR-end bell
Remove the rear-end bell (where the power is connected) by inserting a flat-head screwdriver into the appropriate notches and tapping the end of the screwdriver lightly with a mallet. Insert two screwdrivers in the side notches and apply leverage to pry the end bell from the stator. Be careful not to lose the bearing spring, which often pops out as the end bell is removed.
5. Inspection
Inspect the end bell for unusual wear. Also inspect the terminal board, electrical wiring and windings.
6. Remove the capacitor cover
For motor models that have the capacitor mounted inside a separate capacitor cover, remove the two capacitor-cover bolts using a flat-head screwdriver; then, remove the cover. (Omit this step if the capacitor is installed inside the end bell.) Check the capacitor’s electrical continuity and ability to hold a charge with an ohmmeter or multimeter that has a capacitor test function.
7. Remove the shaft-end bell
Repeat tapping and prying with screwdrivers as described in Step 4 to remove the shaft-end bell. Inspect the end bell for unusual wear; inspect windings for corrosion.
8. Remove the locking-ring screws
Remove the two locking-ring screws from the shaft-end bell using a flat-head screwdriver or 1/4-inch nut driver.
9. Remove the end bell
Carefully secure the rotor in a vise and pull the end bell off the shaft with your hands. If it can’t be removed easily, tap it lightly with a mallet, bearing puller or small hammer. Inspect ball bearings. Clean motor parts of dust, grease and foreign matter.
10. Remove the ball bearings
Using a bearing puller, remove the lock collar, ball bearing and backing plate from the shaft end — and the smaller ball bearing from the opposite-shaft end.
11. Replace the front bearings: Reinstall the backing plate on the shaft end. Install the new bearing. The bearing should only be put on with a bearing press or using a pipe or collar piece the same diameter of the inner race (the steel ring of the bearing that makes contact with the motor shaft), tapped lightly by a mallet until seated against the appropriate shaft shoulder or stop. Force should be applied only to this inner race to avoid damaging the bearing.
12. Replace the rear bearings: Refer to the procedure described in Step 11, excluding the backing plate.
13. Replace the shaft-end bell: Slide the shaft-end bell onto the shaft; tap the end bell with a mallet if necessary. Hint: Thread two appropriately sized through bolts into the locking plate to use as guides when replacing the locking ring screws. (Bolts can be salvaged from an old motor.)
14. Replace the locking ring screws: Replace the two locking ring screws in the shaft-end bell. If you use the hint from Step 13, leave one “guide” through bolt in place while you replace the other; then replace the second screw. Tighten the two screws.
15. Reinstall the end bell: Slide the shaft-end bell back into the motor for reassembly. Be sure to match the alignment marks on the end bell and stator. Tap the end bell lightly with a mallet if necessary.
16. Replace the REAR-end bell: Slip the rear-end bell back into place after replacing the bearing spring. Be careful not to pinch any wires between parts, and match the alignment marks on the end bell and the stator. Tap the end bell lightly with the mallet if needed.
17. Replace the through bolts: Replace the four through bolts and tighten them as you would tighten the lug nuts on a car wheel — that is, a little at a time while rotating from one to another until they are all tight.
18. Test the motor: First, spin the shaft by hand to make sure it moves freely. Then test how the motor runs by connecting electric power, remembering to check for ground before connecting the power. It should run smoothly — like a new motor.
19. Clean the shaft surface: While the motor is running, clean any corrosion from the surface of the shaft by holding a strip of plumber’s sand cloth or emery paper against the spinning shaft. Then disconnect the power source. Note: Use extreme caution while the motor is running. You can also manually turn the shaft to clean this surface.
20. Replace the terminal connection cover: Replace the terminal connection cover and tighten the two bolts.