Anyone had any luck changing one? I don't know if I want to start that job and end up with the car stuck for an extended period of time if I can't get it done.

 

You will need a press to put them on. There are ways to do it without a press but no one
recommends that. Before you start find a shop that can do it for you then just pull the axles,
cut off the collar and take the new bearings and collar to the shop and have them pressed on.

 

Pulling the axles is very easy. I think (if I recall) you need a 12mm box for the backing plate nuts and a block of wood and a hammer (to drive the axles out of the housing). A couple 14mm open end wrenches to loosen the e-brake cable and whatever you would need for a standard brake job (you have to remove the brakes).

I always order the parts and have them ready to go before I pull the axles.
Once pulled, I take everything to my local Mazda dealer and he takes the old one off and presses the new ones on. I like Mazda because they warranty the work. If no Mazda dealer, then take to a local machine shop that has a hydraulic press.

You will need to order (for each side):
Wheel bearing
Wheel bearing collar
Rear Seal (fits inside the axle housing).

RockAuto has some good prices on all of the above.

To install, insert the axles and make sure your splines engage the differential. once you have it most of the way in and you are sure things are meshing, give it a couple small taps with the hammer/wood block to seat the shaft into the diff/housing and bolt everything back up.

Pretty simple repair. and you should be good for another 100K miles.