The door bellow on front loaders do wear out and require replacement. However, overloading the washer can contribute to premature wear or rips and tears due to items getting caught in the seal. If the bellow is ripped, it will require replacing or the washer will leak. The following link explains step-by-step how to install a door bellow on a Kenmore Elite front loader:http://www.fixya.com/support/r385210-replacing_door_bellow_kenmore_elite
Read through the link provided and let me know if you have any questions.
NOTE: There is another method you may try as well. Although I do not prefer this next method because these washing machines are very heavy, an alternative way of replacing the door bellow is to remove the lower toe panel and tilt the washer back at a 45 degree angle instead of removing the washer front panel. If you use this method, make sure it rests against the wall and will not tip forward. This allows the wash tub to drop down and away from the front panel and gives you access to the the rear bellow clamp through the bottom. This can save you some time.
If you would like some helpful exploded view diagrams of your washer that you can reference, you can use any of these web sites:
Just use your model number to begin your search criteria.
If you have any questions, please let me know. I hope this helps you.