Robert, there are a few reasons the Kenmore bags can leak or burst.
First off, were you using generic paper bags? Sometimes, with generic paper bags, the quality isn't the greatest, & they can burst if they are overfilled or used to pick up lots of fine dust & dirt. As for the genuine bags, if you were using the white genuine Kenmore 5055 bags they made back in the 80's & 90's, those were only 1 ply paper bags, very thin & had no microfiltration lining like the yellow paper bags do. Also, the yellow paper bags with the microfiltration lining, whether generic or genuine, they do leak a LOT of dust through the bag material itself, & they will burst if used to pick up fine dust, dirt or ashes because the paper becomes clogged with dust & the air is trying to escape. So part of the problem might be the type of dirt that exists in your home the vacuum is picking up.
To solve that problem, I would use the HEPA Cloth 5055 bags, either generic or genuine. Those bags will not burst, as the material is much stronger than paper, & they don't leak dust. As for the leakage around the collar, that happens because the bag collar can slide up slightly in the bag holder, so not all the dirt enters the hole in the bag collar & enters the bag compartment instead. When you look at how the hose enters the vacuum, you will see that the hose & bag door only touches the foam seal on the bag holder. Most other vacuums have a tube on the bag door or on the hose that goes right into the hole on the bag collar, so all the dirt goes directly into the bag. The only solution to this is to tape the bag collar to the bag holder so it cannot slide up & cause a issue.
Rob
