changing bearings in the align BL700MX

How to properly replace bearings in Align BL700MX


I swapped my 700MX bearings for Boca Orange Seal Ceramic bearings right away. I wanted to run Align motors, but listened to the feedback here on RR on early bearing issues. So I went Boca from the start.

I took some pictures to show the process in case anyone wants to do bearings and was apprehensive about the process.

High level summary of steps
- preheat oven to 225 degrees
- remove rear grub screws securing shaft in back of case
- heat the motor for ten minutes to loosen bearings
- Push shaft out of case
- remove old bearings
- install new bearings
- reassemble motor
- replace rear grub screws.

Remove the two grub screws. They are inside the rear fan slots, set 90 degrees apart.


Heat the motor at 225 for about ten minutes. DO NOT GO HOTTER. Higher temps can ruin windings and mess with magnets.


Pop the shaft out of the case. I don't have a dedicated press. I chucked a 19/64 drill bit backwards in my drill press and used the drill press as a straight press (It was not spinning!!)


This pops the shaft and front bearing out of the case.


Now you can separate the motor parts


Next I used a larger drill bit to pop the rear bearing (just lightly tap the whole thing downwards on the bit, and bearing pops out the top.)


Next remove the bearing from the shaft. I used a 3 jaw puller.


Now for new bearings

Install the new bearings in top and bottom of motor. Use a tiny smear of green locktite on the outer part of the bearing to retain it in the motor.


Reinstall the shaft. Note the hollows ground in the shaft to receive the grub screws from the rear of the case.


Reassemble the motor. You will need to tap the shaft with a rubber mallet to get it back in rear case (gentle here, and make sure the shaft is actually lining up with the hole in the rear case).


Finally, you need to line up the recesses in the shaft with the grub screw holes. I installed the pinion then used a pair of vice grips with a heavy leather glove protecting the pinion. Look in the fan slot (with a flashlight) and line up the recesses and reinstall the screws.


(originally written on RunRyder by jsenicka)