Power Window Motor Replacement
Written by Jay Vessels
When your power windows start to get sluggish, then decide to stop working until you let them cool down for a bit, it's time to tear into the door and have a look. It could be a bent mechanism, misadjusted mechanism, or dry parts, but it is most likely a weak power window motor. If there isn't anything wrong with the mechanism or adjustment, the fix is to replace the motor.
Replacing the power window motor in your Z24 is straightforward, but isn't necessarily that easy. If you're proud of yourself for changing your own oil, you'll want to have this job done. If you don't have any problems rebuilding the rear drum brakes on your car, though, you're probably up to the task. If you've done rear brakes before, you probably have an arsenal of swear words and phrases, too, which will come in handy for this job.
It took me about 4 1/2 hours to do this job, and I've done it before, so plan on taking most of a Saturday to tackle this. The required tools list isn't that long, and is almost all common hand tools. Tools needed: #2 Phillips screwdriver #3 Phillips screwdriver Slotted screwdriver 3/16" and 1/4" drill bits drill for bits Ratchet and sockets (metric and SAE) T45 Torx bit Various pliers Hammer Center punch Cold chisel Rivet gun Lithium grease Tape (cloth body tape or duct tape) 3/16" and 5/32" rivets 1/4"x20 x 3/4" bolts, nuts, and washers 5/16"x18x3" bolt, nut, and washer (approximate, use whatever you have laying around) Loctite ( Blue )
Installation Method
I did this work on a convertible. A hardtop car may be different, because ASC modified these cars into convertibles after GM built the cars. I suspect any big differences are in how the door panel is removed, but the window mechanism may be somewhat different, too. This guide should be close enough to be useful on either body style.
Remove the negative battery cable.
The door panel is split into a few different pieces, and all of them have to come off. First remove the seat belt upper mounting bolt with the T-45 Torx bit. Remove the seat belt upright trim piece, held on with two screws.
Remove the mirror mount cover. This is the small triangle-shaped piece at the top of the door close to the mirror, and it is retained by a single screw.
The door panel is ringed by several Phillips head screws. Remove them. Remove the screw retaining the lower seat belt trim where the seat belt returns into the door. This screw is different from the others in that it is a shouldered screw (it's not threaded all the way to the head of the screw). The lower door panel is also retained by some plastic single-use push fasteners. The panel should pull off, though these pins may put up a fight.
On the convertibles (not sure about hardtops) there is a black plastic shield behind the lower panel. It is retained by the lower door panel mounting screws. It will likely fall off when you remove the panel.
With the lower panel off, there are three #3 Phillips head screws exposed -- 2 under the arm rest, and one at the edge of the panel closest to the latch. Remove these and set them aside. Remove the small trim piece behind the door handle. Remove the #3 Phillips head screw, and the smaller screw. Remove the screw behind the door lock lever. Remove the plastic bezel from around the door handle. The door lock lever is pressed onto the lock rod, and the lock rod will have to be pulled off of the lock lever before the bezel and lock lever will come off. Note the power lock switch connector is plugged in here, and it needs to be disconnected. The upper door panel should now lift up and off of the door.
There is a clear plastic water shield over the door, retained by tape. Peel this shield out of the way, but don't discard it as it keeps water out of places it shouldn't be. It will be reinstalled later.
This picture shows the door with the panel removed.
The power window motor is attached to a black metal plate that is riveted to the door. This plate also contains the window regulator, a large spring assembly that holds the window in place.
This picture shows the regulator attached to the door.
Unplug the power window motor connector. It is retained by a locking tab feature on the wiring connector. Lift the tab (a flat blade screwdriver works here) and disconnect.
There is a small guide channel held in place by two nuts (11mm, or 7/16"). Remove these two nuts and note their position, since this is an adjustment. Remove this channel. It will be retained by a roller on an arm connected to the regulator, and it should slide out sideways.
Note that the regulator assembly comes out next. The regulator is the only mechanism holding the window in place, so now is a good time to wedge or tape the window in a fixed position. The window will likely have to be moved some when removing the regulator, but the window should not be allowed to uncontrollably fall into the door, for fear of damaging the glass. It may help to have a second pair of hands holding the glass when the regulator is removed.
If it hasn't been removed before, there are two kinds of rivets holding the window regulator in place. Some rivets are standard rivets. These are removed by drilling the rivet head with a 3/16" drill bit until the rivet head comes off. Then use a hammer and punch to drive the rivet through the regulator assembly. The other rivet is an aluminum rivet that "peels" open in the back. These rivets have a larger head with a pin center. Use a hammer and punch to drive this pin through the rivet, use a hammer and cold chisel to cut the head off of the rivet, then use the hammer and punch to drive the rivet through the regulator.
Once the rivets are removed, the regulator should be free from the door. It may take some prying to persuade it to come free from the door. Now comes a difficult part -- the regulator is connected to the glass by two rollers, one on each arm. These rollers need to be removed from the window channel by maneuvering the regulator and glass so the rollers and arms slide out of the end of the window track closest to the car interior. This is where that stash of swear phrases comes in handy :) Unfortunately, like many areas of auto repair this is one case where it will come out easily once the "magic" combination of regulator and glass position is found, and this usually only happens after fighting it for a few minutes.
The regulator is a LARGE spring assembly that holds the window in position. THIS SPRING CONTAINS A LARGE AMOUNT OF ENERGY! This spring is dangerous! The ONLY thing keeping this spring from VIOLENTLY unwinding is the power window motor itself, and it's about to be removed.
This picture shows the regulator removed from the door, with the motor still attached.
To keep the regulator from causing injury or death (no kidding), it must be retained. Drill a hole through the sector gear and the backing plate. Bolt the sector gear to the backing plate using a 5/16"x18 bolt (or larger, use what you have on hand). This method comes from the Helm manual -- not my idea -- but it works. Choose a sufficiently strong bolt, too -- mine worked (not sure about what size it was, I had it laying around) but the spring did manage to bend it some, which is not comforting. Note in the picture that I also installed a bolt through the existing hole in the sector gear and backing plate as insurance, but this would not be sufficient on it's own since the hole is too large relative to any appropriate fastener.
This picture shows the regulator being retained by bolts installed through an existing hole, and a hole drilled for this purpose.
With the sector gear locked in position, drill out the four rivets retaining the power window motor, and lift the motor off of the regulator.
Remove the mounting plate from the rear of the old motor by drilling out the two rivets that retain it. Attach this plate to the new motor with 5/32" rivets. Some motors come with mounting hardware, and this will also work. I used blue Loctite on the mounting bolts to make sure they didn't move.
Apply lithium grease to the sector gear teeth and the motor gear teeth, and install the motor. Use 5/32" rivets to retain the motor. If bolts and nuts are used, use blue Loctite to retain them.
Reinstall the regulator assembly in the door. This involves threading the rollers back onto the window track. One regulator arm has a single roller, and the other arm has a roller on each end, one on each side of the arm. Make sure both rollers on the top side entering the window channel are facing the same direction, or you'll have to remove the regulator, rotate the arm, and reinstall. No fun! Unfortunately this is another area where fighting with it until it falls into place is the only method. The rollers won't fit until they're properly aligned with the channel, but once they're in the channel they will move easily.
With the regulator in place, install 3/16" rivets in every hole that a rivet was removed. If I counted correctly, I installed 20 rivets in my door. The regulator and window will be trying to force the regulator out of alignment with the drilled holes in the door, so install the rivets in an X fashion (i.e. install one in the upper right, then the lower left, etc.) to help keep the regulator rivet holes in alignment with the rivet holes in the door.
Some may be tempted to use bolts and nuts for this part, but aluminum rivets are the right choice. It would be difficult to install hardware on the inside of the door, and rivets do a better job of retaining the regulator than bolts -- they withstand shear forces better given the irregularities in the mounting holes than bolts.
Once the regulator is in place, reinstall the lower window channel that was removed earlier, paying attention to reinstall it in the same place as before.
With everything in place, reconnect the battery cable and test the window. It may be necessary to adjust the window, since the lower track adjustment has been disturbed.
Reinstall the clear plastic water shield, and retain it with tape.
Reinstall the upper door panel, the upper seat belt, the seat belt upright cover, and the mirror mount cover. Reinstall the #3 Phillips screws. Reinstall the door handle bezel. Reinstall the screw behind the door lock lever. With the door lock rod in the forward (unlocked) position, reinstall the door lock lever. Reinstall the trim piece behind the door handle.
Reinstall the lower door panel Be sure to install the black plastic shield that fit behind it. This shield is retained by the lower three door panel screws, so align the small holes drilled in the shield with the screws and reinstall.
The seat belt trim is two pieces -- the rectangular piece that covers the seat belt opening, and a long, thin piece that covers the slot in the door from the seat belt opening to the bottom of the door. The thin trim piece hooks into the door panel at the top, and is retained by a door panel screw at the bottom. The seat belt opening trim is retained by the shouldered screw. You're done!
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