I just had another air canister bracket break. I studied why it might have failed and I believe I may have found the problem.
When I put the air canister in place I noticed the nozzle that slides into the oil drain would hang up, so that the nozzle was not down into that tube. Not only did it drip oil all over, but it broke the t shaped bracket.
The solution is to get your hand under the air canister everytime you remove and replace it. You should be able to feel that nozzle and then make sure it is not sitting on top of the drain tube. Then it is safe to tighten the nuts holding it in place.