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.
If you decide to lower the front end of your 911, there is a good chance that your steering will develop what is commonly known as a bump steer problem. When travelling over a bump in the road, the steering wheel will jerk in your hands. The problem is more pronounced if your suspension and steering are stiff. This problem occurs when the tie rods are no longer at the proper elevation for stiff, sure steering. The solution is to install what is commonly known as a bump steer kit. This kit raises the steering rack up to the proper level and minimizes the bump steer effect.
When you decide to lower your 911, I recommend that you install the bump steer kit. If you are simply lowering it down to the stock European specifications, then the bump steer kit is usually not necessary. Install the kit if you are planning on lowering your 911 past the Euro specs (see Pelican Technical Article: Lowering the 911).
Installation is quite easy, and takes only about an hour. As your first step, it's probably a wise idea to jack up the front of the car. Make sure that you place the jack stands in secure locations (See Pelican Technical Article: Jacking Up Your Car), and also make sure that you have more than one backup jack stand.
The next step is to remove the belly pan from underneath the steering rack. This pan protects the rack, fuel pump and brake lines from rocks and debris on the road. The pan is held on with four bolts. On later cars, the bolts also fasten the mounts for the front sway bars.
Now, move to the front trunk of the car. Right behind the gas tank there is a small trap door that covers one of the front blower motors and the steering rack connections to the steering column. With the trap door open, reach down with two 13mm wrenches and loosen up the rack at the point where it mounts to the steering column. This will allow you to raise the rack slightly.
Back underneath the car with the pan removed, remove the two lower bolts that attach the steering rack to the suspension cross bar. Once these are removed, take a long screwdriver and pry up the rack until enough space exists between the rack and the cross bar to insert the spacer. Place the spacer in position, and then repeat the operation for the opposite side. It's normal for there to be significant resistance against raising the rack.
Once the spacers are in place, insert the new mounting bolts that were included with the kit. Make sure that you compare the new bolts to the old ones, and use the new ones that are about 1 cm longer than the original ones. In addition, on some of the older cars, there may be a clearance problem and the rack may not be able to be raised up the full amount. Make sure that you watch for potential conflicts, and shave some material off of the spacers if there is any interference.
Once you have the spacers installed, turn the wheel back and forth several times in order to ease the rack into its new position. Tighten down the steering rack connection point in the front trunk, and replace the belly pan underneath the rack. It's also a very wise idea to have your front-end alignment checked, as the installation of the spacers will alter your front toe-in adjustment.
The bump steer kit comes with 2 aluminum spacers, and two sets of bolts. Made out of high quality, lightweight aluminum, the bump steer spacers will last the life of your car, and do not wear out. Two sets of bolts are included for use on different year cars.
In the front luggage compartment, there is a small trap door that covers the front blower motor, and also the steering rack connections. Before attempting to raise the rack, make sure that you loosen the connection of the rack to the steering column. This will allow it room to move upwards.
The spacers fit between the rack and the cross-bar that holds the entire front suspension. Make sure that you use the proper length bolts when reattaching the rack to the bar.