The top hole must be as large as can be, all the way to the metal sleeve, in order to remove the bushing core. I didn't have a saw that diameter, but by using one slightly smaller and "wallowing" out the hole the core pops right out. If the core doesn't come out easily, then you need to open up the hole to a larger diameter. The diameter of the hole on the bottom isn't as important, you just need to break through the bushing wall into the silicone chamber.
________________________________________ NA to TT, starting from the ground up...
