Antenna goes most of the way down, but not all the way. Managed to get the top nut, spacer, and rubber ring off, but now I can't extract the antenna and drive cable, no matter how hard I pull. I also can't get the motor out because of some strange tube/cable connected to the bottom of the pipe. No idea what to do next. Also, the base of the antenna's pipe looks heavily corroded. Likely due to water damage, but no way to be sure. I've attached pictures as well.

 

I should also mention that I don't hear any noises from the motor when I turn the radio on. I don' think the motor is running at all.

 

So It turns out there was no power going to the motor because power was disconnected. Also, that tube was just a tube for water, and I was able to just pop it off. I disassembled the motor completely and found that the drive cable was broken in 3 places, causing it to jam up everywhere. So I took the pieces out and took the gears out (so they wouldn't grab the motor) but I STILL cannot remove the mast from the motor assembly. For now I'm just going to leave it pushed as far in as it'll go (for some reason it still sticks out 4 inches) and keep the power disconnected. The only reason I wanted to fix this was to take my car thru a car wash since I'm getting tired of always hand washing it.

 

 

If you are just replacing the mast, be sure to make sure there are no broken pieces of cable inside the motor housing. If there are, get them out before feeding the new cable into the hole.