A hammer and a 12" piece of 1/2" round steel or aluminium (1st choice). Slip metal thru axle hole catching the inner race of bad bearing and tap one side then tap the other side alternating back and forth. If you get lucky like I did you'll will be able to reuse the seal. Save the old 6204 bearing for inserting new bearings. Grind down the OD of the 6204 on a belt/disc sander so it slides easily into the hub. On the side that faces the new bearing (press side) grind the inner race to alleviate any possible interferance with the new bearing. Set wheel in the sun to heat up good with the axle installed thru the spacer, bearing in the freezer for about an hour, and wait. A 3/4" washer over the old bearing is a good/safe "beating/pressing" surface over the drive side of old bearing if you using a hammer (lovingly) to insert bearing. After the heating/cooling process grab the bearing with a gloved hand and
quickly install bearing into hub using the axle as your guide. With luck it should go into the bore enough to "press" the rest of the way with old bearing, washer, and hammer. Now if you have a arbor press available great if not a 16 oz. ballpien hammer is plenty. The hammer method is used ALOT in industry do where failure exist in industrial situations. Just use some finesse and only apply pressure on the
OD of the bearing. The seal should slip in most the way then
gently use same method to finish seating it. That done do the other side the same way making sure the spacer is always in assembly when going back together. Also another method is use "all threaded rod" and draw/press the bearing in but again be careful and not to apply any pressure to the inner race.
The 6204 is the outer bearing (non drive side). Don't forget to secure your caliper with a zip tie to avoid any mishap. A good NTH #6204-2RS bearing cost me $12 locally. On a note on bearing designation, the "UU" means the same as "2RS" which = two rubber seals. Now do you need anymore confusion? If so wait around somebody will step up!
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