Antenna stuck 1/3rd or so up? This may help!
Since I bought my car my antenna has been stuck about 1/3rd of the way up and when the radio turns on it would go up a little and stop and thats as far as it has ever moved, before dropping well over $150 from the dealership for a new one or buying a questionable one from the local junkyard I decided to try and fix mine. took all of 2 minutes to take it out
drill the rivits that hold it together, and remove the clips and chances are the nylon cord will want to unwind like a "weedeater" cord.
first clean out all the old nasty grease in the bottom of it. then manually extend the antenna, it may be rather difficult, so keep working it till it will actually come out. Mine was a royal pain to get to to extend. the problem with mine was the second mast was bent which was causing everything to get bound up at that point and stuck. i was able to remove the second mast and gently work the bottom of it with a hammer till it was straight again, and moved freely inside the first mast. then it was just reassembly, I used Synthetic brake caliper grease to lubricate it, I know the recommended lubricant here is white lithium grease, but I do not like its tendency to gum up over time. And more importantly I had this redly available.
It took a little bit of time to properly Index the gear with the motor, as i recall you should have the start of the nylon rope about parallel to the worm gear that drives it. With it lubricated good again reassembly was fairly easy provided you have the antenna extended when you do reassemble, put the clips back on, and get some generic machine bolts and nuts to hold it all together again.
Total repair cost $1.34