All 4 of my 70 442 power windows are slow. One just stops halfway. I plan to tackle each and clean and lube tracks. What else can I do to get back to better operation?

 

I use silicone grease on the tracks, which often helps a lot. The other likely cause is worn brushed in the motors.

 

I agree w/ Joe on suggesting Silicone. That should be your first approach. However, I suggest you test each window individually - one at a time - from each windows separate power window switch; then, perform the same test from the four-window driver's side (door) switch. Is there ANY difference in each windows movement separately from each switch vs. the driver's side switch? The symptoms you describe are not unlike the symptoms I experienced on my power windows. When I ran each window individually from each separate switch, they worked fine - from the driver's door four-window switch each window was intermittent (at best) and sometimes stop half-way, other times work, other times not work at all. I replaced the driver's door four-window switch w/ a NOS driver's door power window switch and all windows work flawlessly. That switch is prone to developing weakness over the years. You're looking at a switch which is 52 years old full of grime, soot, dust, road debris and significantly higher resistance - attempting to push current through a switch full of goobers.

EDIT: And, I forgot to mention significant oxidation of the metal components contained in the switch.

 

That's good advice! I'll have to check the power windows in my 71.