Rear door window motors

[Shawn Blyler]

Warmed up a bit today, so I decided to have a look at the electric window motors in my rear doors. The windows are VERY slow and when it is below 50 degrees or so, need help to raise to the full up position. Ultimately, I would like to put new motors in, but having never done that, it is a bit intimidating. Also, the Fisher body manual I have scares me when I read that you NEVER take out just the motor, as there is tension on the spring and serious injury can result. It says to take regulator and all out together, clamp in a vise and drill a hole that goes through both regulator arms so a screw can be put in there to hold the tension on everything and THEN take off the motor.

I guess the questions are: How in the world do you get everything out like they say through that small hole in the door? Everything that moves in there is dryer than a bone--should I try to lubricate everything and see if that helps before I do all of this, and if so, what should I use? Would it just be a whole lot easier to have a regular auto window place do the job? Below, a pic of the door, with motor showing on the bottom just left of the large hole. (no, that is not rust at the bottom front, it seems to be some sort of spray adhesive stuff that is rust colored) Thanks for any suggestions.

 

[Paul Steinberg]

You need to remove the glass first, and then you need to get the window regulator arms in a position where the unit can be removed from the large hole in the door. If you are not familiar with this operation, I would suggest that you leave this job to the professionals. The man that worked on my 1978 Cadillac didn't heed my warnings, and he came as close to loosing all his finger as you could, with having them sliced off by the regulator. I learned of his foolishness when I saw his hand bandaged, and he told me that the motor was no good. Funny thing is that he blamed the motor, but it wasn't the motor that was bad. It was the fact that he didn't know how to get it back into the door. On the 1978, it is a "trick" unit that has to be in only one position, to get it into the door. If not, then it doesn't go back.

 

[Rick Franklin]

Try cleaning all the old grease in the tracks etc. after 40 plus years, its got the consistency of peanut butter. once the old grease is cleaned out, re-grease it using white lithium grease.

 

[Shawn Blyler]

Try cleaning all the old grease in the tracks etc. after 40 plus years, its got the consistency of peanut butter. once the old grease is cleaned out, re-grease it using white lithium grease.

I will try that out. Then, if it does not improve things, I think I will have the auto glass people come on over and see what they can do. I still have to order the new motors--does anyone know if the rear ones are different on the 75's, as the windows are larger or are they the same as all the other Cadillac models? Thanks.

 

[Paul Steinberg]

GM window motors are the same front and back, and the only thing that changes is there is a right and left hand motor. The earliest motors were a round motor, and later on they switched to a rectangular motor case. I would check www.rockauto.com for the best price on a replacement. Just ask if they are "made in USA", and if they don't know,or they are not, then pass on those and find some NOS ones on eBay or some older auto parts store.

 

[Shawn Blyler]

Okay, thanks. I will check that out as well. I found some rebuilt OEM ones from Convertible Top Specialists in FL that are guaranteed to be made in USA (not as the website states "cheap China units") and even include a new gear for $129 including the $35 core fee.

 

[John ED Renstrom]

but first before you invest in a new motor. do all the checks. make sure you have a good 12 volts to the motor. make sure all you connections are in good shape and that all the rollers are free and rolling. not just sliding in the grove. the door switches are a known problem in those cars they how ever are a easy fix. does it work the same with the master switch as it does with the door switch. if so then make sure it's not binding. but really half the things you need to check or clean up you need to remove the regulator to do. the electrical test you can do in the car. make sure the connection on the motor is good and that it's getting 12 volts. make sure the regulator is tight on the door that's, the ground. it's a simple reversing motor on wire for up the other for down. a good battery and a jumper wire you can test the motor in the door. make sure your connection on the motor is cleaned and take the harness off the switch. ground the battery to the door and with a probe touch the wires at the switch connection. you all ready figured out whitch on is the hot one of the three. the moter will go up or down if it zips up and down your switch is most likly bad or the wire going from the body to the switch is bad or the ground wire for the door is broken and it's trying to ground threw the hinges. if it still drags then it's the motor or it's binding. the hint is back doors don't get used so why would the motor be bad. normally it's dirty. you change the motor you clean and re grease everything it works again. drivers door normally goes out first. but lack of use will set up the grease in the bearings of the motor to. they are not a service able idam

 

[John ED Renstrom]

looking at your pictures I can't tell is one of the bolts missing from the pitch arm? or is it set with the 1/4 inch rivets and they have movement. I don;t think they started using them till 73. the is were the tilt of the glass is adjusted so that it goes up and down level. one of them missing or loose will cause it to bind. the electric motors are hard on these points and tend to loosen the regulator if not just brake it out of the door frame.

 

[Shawn Blyler]

Yes, where you have "reg", those are the regulator bolts. The other points you have pointed out, "adj", are the bolts for the lower channel with rollers for the other scissor arm. The top channel with rollers for the scissor arm is attached to the bottom of the window. I don't see anywhere where a bolt is missing, but I will look at it more tomorrow. I will more than likely have someone who knows what they are doing to look at all of this, it is a bit beyond my comfort zone, and I would like to keep all of my fingers. After reading Paul's story earlier, I guess even the professionals don't always know what they are doing either, but better them than me. Of course, I will show them the page in the body manual about the tension on the spring, etc. Then they will be warned if nothing else. Thanks for all of your help everyone, I appreciate it. Here is more of a head-on shot of the door if it helps any.

 

[John ED Renstrom]

that arm is the pitch adjustment. that why its slotted. it sets the tension on the rollers front or back. so that the leading or trailing edge of the glass, will be higher or lower as it goes up and down. it out of adjustment is the normal cause for the glass to bind. looking I see yours is all the way one direction. it has most likly moved on you and has tipped the glass on the risers. you don't have to worry about the spring unless you remove the motor from the regulator. it is a counter balance spring so that the motor and gears don't take all the weight. put the glass about 1/2 down or up depend on you preference and loosen the nuts. pull the glass up and set the edge level with the straight riser. the pitch arm should move. tighten them back up and see if it works better. my guess is the front side should be more to the center of the adjustment. I hate to see anything maxed out as that is a indication of something is worn out. if the glass sticks a little the motor will move something. this adjuster is normaly it. if you pop the switch out of the trim pad and put it one the haness you can work the glass and see what it is doing.