This tutorial will require some specialty tools. If you are interested in purchasing any of the tools used for this tutorial they are listed as below:
Other important tools:
1/2 inch impact gun
1/2 inch breaker bar
Air hammer with chisel bit
Verify the wheel bearing that’s making noise. On test drive while swaying vehicle from left to right the side that gets noisy is opposite of the direction your turning. For instance, If the wheel bearing noise gets louder while swaying the vehicle to the left the bad bearing is on the right side of the vehicle. Subaru’s are AWD so you can simply lift the vehicle and run in gear. Listen to each individual bearing with a stethoscope. This tutorial will be for a left rear wheel bearing. Now that you have your problem child identified remove the wheel , drum and the 32mm axel nut. If you do not have a 1/2 inch impact gun loose axel nut before lifting the vehicle. Loosen and remove the long 19mm lower control arm suspension bolt. Hopefully it comes out ok for you, I suggest some penetrating oil. Separate the axel from the hub and let it lay down. Re-install the long 19mm suspension bolt. Attach the slide hammer with 3-way slider and some lug nuts then knock out the hub. You can also you the hub remover in the hub tamer kit or even a large brass drift and hammer.
Now that you have the hub removed go ahead and cut off the seal. You now have to remove the inner race off the hub. A lot of the time I will mount the hub in a vise and knock off the race with an air hammer and chisel bit. You have to be very careful as not to damage the hub when doing it this way. Better yet you can use the 2-jaw puller for removing bearing races. It comes in the hub master kit. Now that you have the bearing race removed inspect the hub for damage. The new bearing must fit tightly on the hub. Remove the snap ring located on the outer part of the race. If you are doing a Subaru front wheel bearing the snap ring will be located on the inner side of the race. Set up the hub tamer to remove the bearing race towards the outside. Use either 1/2 inch impact gun or a 1/2 inch breaker bar, 36mm socket and a 27mm for the other end. Once you have the old bearing race removed clean any residual grease left behind.
When installing the new bearing race keep the plastic retainer and bearings in place. Careful as to keeping it clean. There is a Subaru service bulletin stating not to add grease to the wheel bearings. Leave the bearing as is and install. Once you have the bearings and race installed as an assembly remove the plastic retainer. Do not forget to install snap ring and new outer wheel seal. Be sure to pack wheel seal with grease. Configure the hub tamer to install the hub. Install the hub. I have been told to only use the impact gun for removing the bearing or hub and not for installation. I have always used the impact gun for both installation and removal and have never had a problem. I will have to say that it’s easier on the bearing when using hand tools for installation.