Review Dexter's resoruce page and this RV bearing service "how to"
guide. You have to take the outside bearing off to remove the drum. So
service the bearings also when you look at the brakes. BTW Dexter is a
good source for shoes, drums and magnets. Their "populated" backing
plate is a good way to replace all the brake parts easily and economically.
Dexter - http://www.dexteraxle.com/resources
RV http://www.rverscorner.com/articles/bearing1.html#Preload