The exact same thing happened to my XJ. At first, I tried to use superglue, but the it was no match for the spring pressure, and the button popped off again and hit the windshield
Originally Posted by CherokeeJay
the metal rod that runs the lenght of the plastic tubing fell out.
In mine, the metal rod was still in the brake lever, but it sort of fell back into the lever so you can only pull on it with needlenose pliers. I'm assuming that's what happened to yours.
It makes it a lot easier to fix if you take the console out. When I took my console out, there was a rectangular hole near the base of the lever on the driver's side (at least it's that way on mine). You should be able to see the metal rod through that hole. I used a screwdriver to hold that rod up while I glued the button back on with gel-type superglue.
Here's a tip for the glue. Put a tiny amount of glue in the button cap and let it dry partially so that it makes the hole a little smaller. Then, just before you're ready to put it back on, add some more glue. The dried part will help hold the button on the threaded rod so that the spring doesn't pop it off again while the other glue is drying.
Let me know if you need any advice on getting the console out.