Hopefully the pressing tool has all the right adapters and make sure they start straight. Also, you do know the uppers are screwed in--right? Make sure you get the socket for it, and be just as careful making sure they go in straight. I used a 1/2" breaker bar and a long pipe to get them unscrewed, switched to a ratchet when they broke loose.

BTW, a LITTLE heat will help, you just want enough to help break things free, but honestly, I never used heat on any B/joints I have done.