This article is one in a series that have been released in conjunction with Wayne's book, 101 Projects for Your Porsche 911. The book contains 240 pages of full color projects detailing everything from performance mods to changing your brake pads. With more than 650+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any Porsche 911 owner's collection. See The Official Book Website for more details.
Have you gotten tired of having to open your door and get out to retrieve your burger at the drivethru? Perhaps it's time to replace your window regulator, or power window motor. The difficulty of this project varies depending upon which year car you have, but the results are immediate and quite rewarding. Not much is better than driving in your 911 with the sunroof open and the windows down on a nice sunny day. Having a broken window regulator can surely put a damper on that.
The first step in replacing either the regulator or the power window motor is to remove the door panel. For cars equipped with power windows, disconnect the battery as well before you start. Make sure that you eliminate the power window motor as a potential problem before you start tearing into your door. Double-check all the fuses that control the power windows, and swap out the relays to make sure that there isn't a problem with them. If one of the windows works and the other doesn't, then chances are that it's the window motor or the window switch.
For details on removing the door panel, see Pelican Technical Article: Door Handle Replacement. When you have the door panel removed, check the window switch to make sure that it's working properly. Try swapping the two switches, or plug in a new one. If there still is no response from the window, then the motor probably needs replacing. Check to see if power is getting to the motor when you press the switch. Of course if there is plenty of noise coming from the door and the window isn't moving, then it's quite obvious that the motor is fine, but the regulator needs to be replaced.
Make sure that you remove the door's speakers as well, if your 911 is so equipped, and that the window is rolled down (if possible). Reach down into the door through one of the access holes and remove the power connections from the motor. Make a note of which connection goes where.
Now remove the bolts that hold the window regulator inside of the door. These will require a hex key set. Although the entire process can be done with the door attached to the car, gravity has a tendency to make the job a bit more difficult. Removing the door is not an easy job, however, if for some reason you are planning on removing the door at a later date to do some work on it, now would be a good time.
After you remove the bolts that hold the regulator and motor assembly to the door, the regulator should be able to be moved around inside the door. Be careful not to scratch the glass when you are moving items inside the door. Maneuver the regulator so that you can see the three bolts that attach the motor to the regulator. Unbolt these three, and remove the motor from the regulator. Be careful when you remove the motor, as the window spring may make the regulator spring around a bit inside the door, and you want to make sure that it doesn't scratch any of the window glass. The motor can be tested on a bench by applying 12 volts DC to the two terminals. If it doesn't turn, then chances are that you have a broken window motor.
After the motor is removed, you should be able to slide the bottom part of the regulator off of the track that is attached to the window glass. Push the glass up to the top, and tape it to the top channel of the door. After the regulator is free, it should be relatively easy to pull it out of the door.
Inspect the regulator for wear. It should be relatively easy to figure out if the regulator is broken. The usual points of failure are the plastic rollers, and also the points where the regulator pivots and is riveted to itself. If you have a new regulator on hand, compare it to the damaged one, and you should be able to see the problem.
Installation of the new regulator is straightforward. You might have to negotiate the alignment of the window and the attachment of the motor inside the door. It make take one or more tries to get it right. The regulator spring is designed to be compressed when the window is lowered, so it might be easier to reinstall if the window is raised about 3/4 of the way up the channel. Lubricate all moving parts of the regulator with white lithium grease prior to the installation. Make sure that you also spread plenty of grease on the plastic wheels and inside the track at the bottom of the glass.
Before you reinstall the regulator, it's probably a wise idea to inspect and replace the window channel guides if they are worn. These are the two channels that guide the window as it is raised and lowered by the regulator. They can be removed from inside of the door. Also worth replacing is the window slot seals. These inner and outer "window scrapers" keep water from dripping down into the recesses of the door.
Before you close everything up inside your door, it's probably a wise idea to test the proper operation of the window. Hook up the power connections to the window motor, and try to raise and lower the window. Or, if you have manual windows, install the crank and see if the motion is smooth and uniform. Also make sure that you adjust the stop positions of the window once you have reinstalled the regulator. There are screws located on the regulator that control these stop positions.
Unfortunately, this procedure works best for the 1974-89 911s. On some of the earlier cars, the opening in the door is not large enough to remove the regulator. Instead, the entire window frame and glass must be removed as well, and the regulator pulled out of the top of the door--this varies by car (for example: 1969 912 this is not necessary).
The window regulator is one of the more common items to break on the 911. Plastic wheels on the regulator combined with regular wear causes them to break and the window to stop working. The motors seldom fail, but when they do, they can be expensive to replace.
This photo distinguishes the six bolts that fasten the regulator to the door from the other bolts that hold on the window channel and the door lock mechanism on a 911SC. After you remove these bolts, you should be able to rotate the regulator so that you can access and remove the window motor. Changes in regulators over the years result in different mounting and adjustment methods. The general procedure is the same for late-model cars.
These three bolts fasten the window motor to the regulator. Be careful when you remove the motor, as the spring on the regulator will snap back, and the resulting movement can damage either the window glass, or the door lock mechanism.
With much negotiation, the window regulator can be removed from the lower part of the door. Rotate some of the arms into the correct position in order to pull the regulator out of the door. Make sure that you have the window pushed up all the way before you try to remove the regulator.