96 Toyota 4Runner... also this is my first Toyota.

FIRST QUESTION?...
I have been having a major vibration and in slower speeds a banging noise like a hammer on the bottom of the car. I have come to think it is the forward U joints. There are 2 in this section. I have only changed U joints ones before. Would it be better to take the drive shaft off and take it to a shop and have them press them out and install new ones? or are they pretty simple to do myself? so is this knocking vibrations thing a common sign for the U joints going bad?

SECOND QUESTION?... is it normal for the brakes to feel like you are stepping on bricks and sometimes not to stop completely when on ice or in slippery rain? some people say it is a Toyota but I feel like I might have a crash... I even replaced one drum, rotor ans all springs on rear after changing a rear pinion seal. can the brakes be tightened or anything to make me feel safer and to get the car to stop when I need it to stop? i have put pads and shoes on.