Volvo Repair: replacing antenna mast, antenna mast, plastic strip

Question
I have a 1990 740 Volvo Turbo and I need to replace the antenna mast. I got one and tried to replace it. The plastic strip didn't go all the way down so I trimmed some off. But when I tried to make the antenna go down when I turned off the radio it would not grab to go down. What am I doing wrong.

Answer
sorry this is a feel thing. you just need to feel when it goes down. you are catching on a lip inside the sleeve for the motor. you must go down about another 1/2 to one inch. then the motor will grab the splined cable. and if it wasnt grabbing it before, wouldnt trimming some off, only make things worse?