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.
As the 911s get older, one of the most irritating things that can happen is that they begin to leak water. Although most Porsche owners don't drive their car in the rain, the occasional unexpected downpour can considerably soak up one's interior carpet. The solution, of course, is to replace the seals that are leaking.
Two of the most common seals to leak water are the sunroof seal and the front windshield seal. The sunroof seal replacement is easiest when the sunroof has been removed. See Project 85 for more details. The front windshield seal that mates the glass to the car can only be replaced with the removal of the windshield. See Project 79 for more information on this removal process. The installation of new seals in the front, rear and side windows is documented in Pelican Technical Article: Installing Window Glass. The door seals on the coupes have a tendency to leak after many years. On the targa and cabriolet cars, there are quite a few more seals that can leak, such as the windshield frame-to-roof seal, front targa bar seal, and the two side targa top seals.
The first step in solving water problems is to determine where they are coming from. Have an assistant sit inside the car as you spray water on it with a hose. Aim the water at specific areas of the car, starting with the lowest points first. Make sure that you wait a few minutes before moving to a new position. If you have patience, this method will pay off, and you will be able to figure out where the leak is coming from.
If the door seals appear to be leaking, then this is an easy fix. New coupe door seals are relatively inexpensive at about $40 each. To remove your old door seal, simply take the seal and pull on it. It should be lightly glued into the frame of the door, and should only require a moderate amount of force to remove it from the doorframe. Then test fit the new seal to the door, making sure that it fits well and is the proper one for your car. For installation, the new seal should have a very light coat of 3M Super Weatherstrip 80001 (see Pelican Technical Article: Engine Sound Pad Installation) applied to the edge that meets the doorframe. Insert the seal all the way and make sure that it makes appropriate contact with the metal inner groove. Close the door and let the glue dry as the door compresses against the seal. You probably want to keep all your windows open, as the smell from the glue can be pretty powerful.
Targa and cabriolet owners have a significant disadvantage when it comes to keeping water out of the car. Because of the design of the roof, there are several more places that need to mate properly to keep water out. First and foremost are the windshield frame-to-roof seal, and the front targa bar seal. These seals have a tendency to become dried out, brittle, and cracked over many years of exposure to the sun.
Replacement of the windshield frame-to-roof seal is an easy task. Simply remove the old seal from the metal channel in the car by pulling on it. You may have to cut and slice a few pieces out of the channel, but if the seal is old, it should come right out. Make sure that the channel is free of any remaining rubber pieces and glue before you start installing the new seal.
Test fit the new seal in the channel to make sure that it will fit properly. You may have to stretch the seal a bit to make it fit entirely across the car. This is normal, as there shouldn't be any slack in the seal. Start with one side of the car and prepare to glue the seal by placing a bead of 3M Super Weatherstrip along the side channel. Slide the seal into the channel and make sure that it is fully seated against the metal and the glue. Press the seal into the channel, and close the door to let it seal. Wait about five to ten minutes for the glue to dry before you start on the top.
Move to the top of the windshield and carefully place a bead of glue in the upper channel, as well as down the opposite side. Be careful that you don't spill any in your interior. The glue has a tendency to become stringy and can leave long strands that can drop down into your interior. Stretch the seal all the way across the windshield frame and make sure that it fits into the other side before you push it against the glue in the metal track on top. When you have finished gluing in the seal, place the top on the car, and also close all the doors so that the glue can dry while the seal is in its proper position.
The front targa bar seal at the rear of the roof is similar to the windshield frame-to-roof seal, with a few caveats. In addition to the glue, small plastic rivets hold the seal in place. These rivets contain small serrations that lock the rivet in and keep it from popping out. There are four of these plastic rivets that help to keep the seal firmly mounted to the targa bar. In addition, you must make sure that the two large holes that locate and accept the pins on the targa roof are lined up with the receptors in the targa bar. Glue the front targa bar seal in a similar manner to the windshield-frame-to-roof seal , working from one side to the other.
The side seals on the targa top roof are also another source of major leaks. The good news is that these are very easy to replace. They are simply attached with four small screws to the sides of the roof. Remove the screws from the old seal, and attach the new one. You shouldn't have to use any glue or sealing compound on the new seals.
Well, these are the major problems with water leakage in the 911. There are other seals that might also leak after many years, but if you replace the ones shown here, you will probably have a 95% chance of staying dry.
Replacing the door seal is an easy job. Simply pull out the old one from the door frame. Then make sure that all the left over glue and seal pieces have been removed from the channel. The new seal simply glues in place inside the channel. Shut the door and leave the windows open when you let the glue dry.
The front and rear targa seals are similar to the door seals in that they fit inside a wide channel. Remove the old seal in a similar fashion: pull it out from the car. Then install the new seal using the 3M Super Weatherstrip. Make sure that you start on the side and glue the seal in the groove as it goes around the top. Test fit the seal first to make sure that it will fit before you start any gluing.
The targa side seals are also a common place for leaks to start. The seal itself is a complex part, consisting of both metal and rubber pieces. On the older seals, sometimes water leaks into the seal and can cause the embedded metal to rust. Replacement is quite easy as the old seal is simply unscrewed from the roof, and the new seal installed in its place.