Hello,
You can find a lot of information on this process in the "rear axle" and "rear wheel bearing" information on this site. Yes they are a bit complex but not that bad a job if you have the information in front of you. Normally these little shoes do not wear out, since they are iused when the car is not moving as a parking brake.
Accidentally running with the emergency brake on or damage from corrosion can result in the need to replace these small shoes .
The early workshop BBB has a fairly good description of the procedure (Sec. 42-28) also.
