Usually, you do not need to replace the trackpad!
When you remove the bottom cover by using a pentalobe 1.2 screwdriver, you will realize that there is a screw in the middle of the area between the trackpad and the edge of the computer. It is a small philips screw. You probably need to loosen that one. Not too much though, because it might stop registering the clicks. Sometime 1/4 of a full rotation might work. You will need to experiment with this.
Moreover, when you are putting the bottom cover back, the amount of tightness applied to the outer screws will have an affect on how it is going to work. You also need to optimize the tightening level in those screws.
I switch on the "tap to click" option (under Apple > System Preferences... > Trackpad) for a week. But now it has fixed itself as if by magic. Crumbs? – Tom Hawtin - tackline – 2011-03-13T17:02:53.097
It went bad again. After I had my screen replaced it came back working but not well enough for me to switch back from tap-to-click. – Tom Hawtin - tackline – 2013-03-05T16:21:27.833