hey i bought a 940GL wagon a few years ago. I have found that it used to have a power antenna but it was snapped off and too expensive to replace. This meant the owner bought a standard non-power replacement. This replacement is now broken so i am going to my local junkyard tomorrow to see if i can find a replacement for the power antenna. I have checked what i have in the car already but im not sure how it all works. I have:

The switch, still in the dashboard wired to a motor in the trunk (which was unplugged)
The motor (still works)
Two pipes coming out of the motor, one black, one clear. The black one is full of lubricant and has a sort of toothed line on it (must be for pulling the antenna down).

can anyone explain to me how these twon lines work and how easy it will be to fit another antenna to the old motor? My haynes manual doesnt really describe it very well and i have no way of dismantling it as the parts are missing.

any help?