I have an '81 and the rear power window will only go down halfway and then stops. It'll go back up from there but coming down, stops at about halfway again. I've taken the access panel off and sprayed WD40 over the places I think need it, I've cleaned the glass in case it was sticky but now I'm at a loss.
Does anyone have any suggestions? I'll try anything at this point.
Thanks in advance.
Jamie

 

While a friend operates the window... try tilting the glass in or out as it comes down. You are probably just gonna have to pull the cover and dive into what's going on in there... be careful not to break the glass as they are very hard to find.

 

Ok yeah, I'll give push-pulling the glass a shot. It's just starting raining here though so it'll have to wait
I've got the cover off and I've cleaned off the old sticky grease as best I can using WD40 and some old fashioned elbow grease and I've re-lubricated the gear teeth where they meet behind the locking mechanism and I've lubed the teeth where the motor cable meets a gear box. I've also tried to lubricate where the arms hold the glass as I get the impression it pivots there as it comes down. I think maybe now it needs the careful but forceful action you mention.

 

Pull the drive cable off of the power window motor and hook it up in your drill. Cycle the regulator manually with the drill to see if it encounters any hard spots.

 

So i tried what you said with the battery drill. Is is possible that the cable between the motor and the mechanism is getting caught up? I ask because the drill managed to get the window down to where it sticks and then when it got there the cable itself started twisting around itself and bunching up. I guess thats because the drill has more torque than the motor, the motor quits at this point where the drill didnt.
If I need a new cable, where would you guys suggest going for that? Would I be able to pick one up from the Dealership by any chance?

 

Sounds like there is something wrong with the regulator. The cable likely turns more than one rotation to get to where the window sticks, correct?

I would remove the regulator and work it on the bench to see if you can notice what is happening.