Re: Pipe assy under kitchen sink
The neck of the disposal pipe should go inside of both the washer and the mating piece of pipe. If the washer isn't going onto the pipe, then it's either too small or it's gotten too hard to stretch or expand. Replace the washer with one that will fit the pipe. I'm suspecting that part of your problem is that you've got the wrong washer. When you go to purchase a replacement washer, look for the pieces of pipe you're working with. They should come with washers, match your replacement to what's in the package. Washers can be purchased separately.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!