Often you can help a balky antenna mast by lubricating it. Spray silicon or WD40 work well. Clean as much of the grunge as you can off from the mast while it is fully extended by using one of the above mentioned lubricans on a rag. Lower and raise the antenna several times to expose as much of the grunge as possible. Then spray the mast with one of the above lubricants and again lower and raise the mast several times. You want to end up with a very light coat of lubricant. Grease of any kind, including silicon, does not work nearly as well. Doing this two or three times a year seems to be all that is really needed. Although my mast is starting to show some pitting, it is still original and works well at 186,000 miles.
