Before installing your new mast, compare the old mast with the new one. They need to be identical in every way.  If they are different, you may have an after market power unit.  Also it is very important that you NEVER cut the white cable on the new mast at any time.

    1. Remove the nut on the outer end of the power unit where the mast comes out of the car.

    2. As someone turns the radio on and as the mast begins or tries to come up,... grab hold of it and pull out the old mast...taking note which direction the teeth on the plastic cable are facing so you know which way the new mast cable is to face when you put it in.

    3. Compare the old mast with the new one, the length of the white teethed cable MUST be the same length of the one you took out of your power unit (DO NOT CUT THE NEW MAST CABLE).... If the cable is not the same length, then you probably have a broken piece left in your power unit.... If the cable is shorter proceed with step 4.... If the over all length of the stainless portion of the mast and diameter are the same along with the white cable length continue with step 5.

    4. There are occasions where the antenna cable breaks off in the power unit and will not allow the replacement mast to be pulled in all the way. In this event you will have to remove the power antenna assembly from the car and disassemble the drum assembly and manually remove the broken portion! Once the cable is out, clean the grease off of the drum assembly before you reassemble the power unit. Once this is done, use a light grease or white grease on the drum assembly, then reinstall the power unit in the car and proceed with step 5.