Pieces of the lower dishrack were loosing the plastic coating and snapping off.

First of all, I removed the existing lower dishrack. That was a piece of cake! The part that was tricky was getting the spray arm out of the center so that it could be placed into the new dishrack. I finally figured out that I simply had to twist this piece (I think to the right) to remove it. I reversed this step to place the spray arm assembly into the new dishrack. And then VOILA...I just slid the new dishrack in place!