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Suspension Overhaul of your Porsche 911 Carrera
 
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Pelican Technical Article:

Suspension Overhaul of your Porsche 911 Carrera

Time:

20 hours20 hrs

Tab:

$200 to $3,000

Talent:

***

Tools:

Thin wrench set, pickle forkball joint tool, Torx driver set

Applicable Models:

Porsche 996 Carrera models (1999-05)
Porsche 997 Carrera models (2005-08)

Parts Required:

Control arms, wishbone brackets and bushings, tie rods and boots, sway bar bushings and drop links

Hot Tip:

For a complete suspension overhaul, replace everything that can possibly wear out

Performance Gain:

Tight, crisp handling

Complementary Modification:

Replace shocks and springs

There are lots of bushings and joints on the 911 Carrera suspension that can wear and become loose after many miles of driving. If your car's steering wheel vibrates when traveling on the highway, then there are most likely components in your front suspension that need replacement. In general, I recommend replacing every wearable part in the suspension every 80,000 to 100,000 miles. This will assure you a crisp, firm-handling ride. There are four main components that need attention when you overhaul your front suspension: control arms, ball joints, sway bar bushings, and tie rods. On the Carrera, the rear suspension is a similar, slightly different version of the front - replacement procedures are almost identical. The PelicanParts.com online catalog has complete replacement kits with everything you need for your overhaul, making the job of acquiring the parts substantially easier.

Tie rods: One of the most common parts to replace are the tie rods. These rods have two universal joints on each end and control the angular position of each front wheel when the car is steered. If the tie rod's joints are worn, then precise steering is impossible, and the car will also have wobbly front wheels and a possible alignment problem. Sometimes vibrations in the steering wheel can be caused by worn out tie rods too.

Replacement of the tie rod is relatively simple - if you have the proper tools. Each tie rod is attached to the wheel bearing carrier with a beveled fit. This means that the tie rod is securely pressed into the spindle arm and cannot be removed without a special tool. The best tool for removal is an angled pitchfork tool, called a pickle fork, that is designed specifically for this task. Do not attempt to hit the top of the rod end with a large hammer, as this will only serve to bend or damage your strut. Place the pickle fork tool in between the strut and the rod end and then hit the tool repeatedly with a large hammer. The wedge in the pickle fork tool will drive the rod end out of the arm. You may have to hit the pickle fork tool quite a few times before the rod end will pop out of its location.

Start by removing the top self-locking nut with a Torx socket wrench (Figure 2). Place the pickle fork tool in between the spindle arm and the rod end and then hit the tool repeatedly with a large hammer (Figure 3). The wedge in the pitchfork tool will drive the rod end out of the arm. You may have to hit the pitchfork tool quite a few times before the rod end will pop out of its location.

Once you have the outer rod ends disconnected, remove the boot clamps that attach and secure each end of the rubber boot (bellows) to the tie rod and the steering rack. You will see the exposed metal shaft of the steering rack. Make sure that you don't get any dirt or debris on the rack while you are working on it. Now, it's time to unscrew the old tie rod from the rack. This sounds easier than it really is. The old tie rod may be quite snuggly secured to the rack and could require significant force to remove it. There are a few specialty wrenches designed for this purpose, but I've always had good luck with channel locks and/or a plumber's wrench.

Before the final install of the new tie rod, place the new one and the old one side by side on a workbench, and adjust the new tie rod so that the length from the rod end to the rack-mating surface is the same. You want to set the two lengths of the tie rods to be equal so that you can minimize the change in alignment of the car (Figure 4). You will have to get the car realigned regardless, but it's a good practice to get the alignment close so that you can safely drive to the alignment shop. Mark the final position of the tie rod end on the new tie rod (white paper correction fluid comes in handy here), and then remove it. Don't install the new rod end yet.

Before you screw the tie rod into the rack, make sure that you spread a few drops of Loctite or Permatex Threadlocker onto the threads. After you insert the tie rod into the rack, use a pair of large vise grips or channel locks to tighten it down. There really isn't too much to grab onto with a regular wrench, and chances are you won't have the special thin wrench that is required to tighten the tie rod. The torque specification for the tie rod to the rack is 59 ft-lbs (80 Nm).

Once the tie rod is tight, then place the rubber boot over the tie rod and onto the steering rack. You will have to remove the rod end on the end of the tie rod in order to make the boot fit. Use pliers and screwdrivers to stretch the boot over each end. Once the boot is in position, install two new clamps over the two ends of the boot to secure it to the rack housing.

After the boot is installed, reattach the tie rod end. Make sure that the length of the tie rod is the same as the measurement of the old one. Adjust the position of the rod end to match up with the mark that you previously made when you compared it to the original tie rod. The torque specification for the tie rod end to the wheel bearing carrier is 37 ft-lb (50 Nm).

To complete the job, install the new rod end into the front control arm. Perform the same procedure for the opposite side. The car should be taken straight to an alignment shop, as it is very easy to mess up the toe-in of the front suspension when you are replacing the tie rods. If you are planning on performing any other front suspension work that might affect the alignment, it would be advisable to do it now, since you will have to realign the car anyway.

Wishbone / Control Arms: The 911 Carrera uses two separate components to create a virtual A-arm suspension that integrates four joints - two ball joints, one center connection, and one rear rubber bushing. Many suspension problems can be traced back to worn out control arm/wishbone ball joints or bushings. Shaking of the steering wheel at high speeds is a good indicator that the control arm/wishbone bushings are worn, the ball joints are worn, or the control arm itself has become bent.

The ball joints, located at the bottom of the strut and attached to the chassis end of the control arm, help the entire assembly pivot and rotate as the control arm turns and pivots and the suspension rides up and down. Needless to say, these critical components can wear out over time and should be replaced every 100,000 miles or so or if the front suspension is beginning to feel a little wobbly.

Both ball joints are integrated into the two assemblies and are not replaceable (you must replace the entire control arm and/or wishbone). Removal of the control arm involves the following steps: disconnect the inner ball joint, and disconnect the attachment point to the wishbone (see photos).

The wishbone removal requires that you disconnect the wheel bearing carrier from the wishbone (attached with the outer ball joint) and the control arm. For the outer ball joint, the nut is easily accessible on the lower part of the strut. The ball joint is attached with a beveled fit, similar to the tie rod ends. This means that the ball joint end is securely pressed into the spindle arm and cannot be removed without a special tool. The best tool for removal is the angled pickle fork tool discussed previously. Installation of the new ball joint, that is integrated on the wishbone, is easy - simply insert it into its hole and tighten down the nut on top. Follow the photo array in this project for guidance on which components need to be disconnected for replacement.

Sway Bar Bushings: As 911s age, the tendency is to find them with worn-out bushings, particularly the sway bar bushings. The first step in replacing your bushings is to figure out if they need to be replaced. Carefully inspect them for cracking, and also check to make sure that their inner diameter hugs the sway bar tightly. If they do not appear to be worn, then simply apply a little bit of lithium grease inside the bushing. If they are worn, then they will need to be replaced.

Replacing the bushings is very easy. With the car elevated and the front wheels removed, simply disconnect the bracket that holds on the sway bar bushing (see Figure 7). The bar and bushing together should drop down slightly if you release both sides at the same time.

The new replacement bushings are split down the middle, so they should easily slide onto the bar and into the bracket (see Figure 9). Remove the old bushings, and insert the new ones, making sure that you coat the bushings with some white lithium grease on the inside.

The sway bar drop links are an easy replacement too. Both the top and bottom parts of the drop link contain small ball joints that attach to the strut tower and the sway bar. Remove the nut from each of the two mini ball joints on each end of the drop link. The small ball joint may present a bit of a challenge - you may need a special thin wrench to remove the retaining nut (see Figure 8). Installation of the new drop links involves simply bolting them into place while holding the ball joint from spinning using your thin wrench. The replacement of the rear sway bar bushings is nearly identical to the front.

It's important to note that you should always use brand new factory hardware when replacing your suspension components. Most of the nuts and bolts used in the front suspension have self-locking compounds impregnated into their threads. Reusing old hardware can result in nuts or bolts coming loose and causing a dangerous situation.

A large portion of the front suspension is covered by a large plastic tray.
Figure 1

A large portion of the front suspension is covered by a large plastic tray. Remove this tray prior to working on the front suspension. The tray is held on with small metal clips that need to be pried off and also a few plastic nuts that need to be removed (lower right). The lower left shows the two crossbraces that need to be loosened and moved out of the way if you are removing the sway bar.

Removal/installation of the outer tie rod is started by holding the inner ball joint with a Torx T30 driver and turning the nut.
Figure 2

Removal/installation of the outer tie rod is started by holding the inner ball joint with a Torx T30 driver and turning the nut. Once the nut is off, then you can use a pickle fork tool to pop the ball joint out of the wheel carrier (see Figure 3).

The steering tie rods are removed in a similar manner to the ball joints.
Figure 3

The steering tie rods are removed in a similar manner to the ball joints. The pickle fork tool is essential for popping the tie rod ends out of the end of the strut. Proceed cautiously, as the rubber boot can easily be damaged when you remove the tie rod end. However, if you are replacing the tie rod end anyways, then this shouldn't be a concern. You can also use a clamping tool like the one shown in Figure 4 of Pelican Technical Article: Replacing Wheel Bearings on your Porsche 911 Carrera.

Before you install the new tie rods, you should attempt to get each one as close as possible in length to the originals (the distance between the green arrows should be the same).
Figure 4

Before you install the new tie rods, you should attempt to get each one as close as possible in length to the originals (the distance between the green arrows should be the same). Place them on your bench and compare the lengths, then mark the position of the tie rod end using some white correction fluid (small white arrow). Adjust the new ones as necessary to the lengths of the old ones. This will enable you to get as close as possible to the toe-in alignment adjustment. You will still need to take the car in for an alignment, but you want to get as close as possible to minimize tire wear while you're driving to the alignment shop.

Shown here are several steps in the tie rod installation process.
Figure 5

Shown here are several steps in the tie rod installation process. A: A good tool I've found to remove tie rod ends is a plumber's wrench. I've had good luck removing the tie rod ends with this tool, especially when access to the area is tight, as it is on the 911 Carrera. B: The new tie rods are screwed into the ends of the steering rack. Although there is a torque specification for this, it's nearly impossible to measure without the use of a special installation tool. I typically tighten it as tight as I can using the plumber's wrench. Add some Loctite or Permatex Threadlocker to the assembly as well, as shown in Figure 6. C: Pre-fit the boot and clamps, and slide them onto the tie rod. D: It's an understatement to say that the OEM clamps are a bit difficult to work with. I believe that they are meant to be used during the car's assembly when good access can be had to all areas. So instead, I typically use standard hose clamps, which I feel are better constructed and easier to install.

On just about every other car I've worked on, there are locking tabs that act as a stopgap measure to prevent the tie rods from backing out of the steering rack.
Figure 6

On just about every other car I've worked on, there are locking tabs that act as a stopgap measure to prevent the tie rods from backing out of the steering rack. Surprisingly, the 911 Carrera lacks these, so I prefer to apply some Loctite or Permatex Threadlocker compound to ensure that the tie rods stay in place. Carefully clean out the inside of the steering rack prior to screwing on the tie rods with the Threadlocker applied to the threads.

The front control arm (white arrow) is attached to a boomerang-shaped plate (orange arrow) that is bolted to the bottom of the chassis.
Figure 7

The front control arm (white arrow) is attached to a boomerang-shaped plate (orange arrow) that is bolted to the bottom of the chassis. In order to loosen the control arm connection and remove the sway bar bushing (green arrow), remove the two bolts on either side of the sway bar bushing (yellow arrows) and the large bolt at the rear (red arrow). You do not need to remove the bolt indicated by the light blue arrow. Finally, rotate the boomerang out of the way (dark blue arrow).

The drop links (green arrow) may present a challenge to remove, as the ball joint on the top of the link may spin when you try to remove the outer nut.
Figure 8

The drop links (green arrow) may present a challenge to remove, as the ball joint on the top of the link may spin when you try to remove the outer nut. If this happens, you will need to use a thin wrench (yellow arrow) to hold the ball joint in place while you loosen the nut. You can purchase a set of these wrenches that are specifically designed to fit into places where a normal, thick wrench will not (available in the tools section of the PelicanParts.com online catalog). They are typically about an 1/8 of an inch thick and are a very useful tool to add to your arsenal.

Solid sway bar bushings are essential to good handling.
Figure 9

Solid sway bar bushings are essential to good handling. To perform a complete renewal of the front suspension, you should replace the sway bar bushings and drop links as well. The bushings have a slit down the center so that you can easily pry them on and off the sway bar.

Shown here is the top view of the front suspension.
Figure 10

Shown here is the top view of the front suspension. Since the front shock has been removed, the assembly must be supported by the floor jack (blue arrow). The brake caliper is tied up and hung from wire on the left (purple arrow). The tie rod is connected to the wheel carrier as shown by the orange arrow. When removing the shocks, you need to loosen the main bolt that attaches the wishbone to the chassis (yellow arrow). Don't remove it; only loosen it, as this will give you enough free play to drop the assembly down and remove the front shocks. The control arm is connected to the center of the wishbone (red arrow), and the boomerang-shaped plate shown in Figure 7 (green arrow). Finally, this photo also shows the sway bar (white), which has been disconnected from its drop links (not shown).

This photo shows the main components of the front suspension on the Carrera.
Figure 11

This photo shows the main components of the front suspension on the Carrera. A: This is the wishbone, and it supports the wheel carrier, which wraps around the shock and contains the wheel bearing. B: The control arm constrains the movement of the wishbone so that it travels in a mostly up and down manner. C: The inner tie rod attaches to the steering rack and is mated with the outer tie rod (D). Changing the effective length of the tie rod assembly (C and D together) changes the toe-in alignment specification for that side of the car (see Pelican Technical Article: Alignment in your Porsche 911 Carrera). D: The outer tie rod attaches to the wheel carriers and transmits steering input from the rack to the carrier.

Although I haven't quite seen it yet on the 911 Carrera, this steering column rubber coupling tends to age and wear out on other cars.
Figure 12

Although I haven't quite seen it yet on the 911 Carrera, this steering column rubber coupling tends to age and wear out on other cars. At this time (2012), the only way to replace this coupling is to replace the entire steering column. At $1,600 or so, that's a bit cost prohibitive. I suspect that as these cars age, an aftermarket replacement part will become available.

There's a night-and-day difference between a new and used rack.
Figure 13

There's a night-and-day difference between a new and used rack. The inset photo shows a Genuine Porsche rebuilt power steering rack-and-pinion assembly. If the rack wears out, then you will find that your steering will be sloppy. Also common are leaky racks that deposit power steering fluid on the floor of your garage. Be aware though--sometimes it may only be the power steering lines that are leaking and need to be replaced--not an expensive rack (green arrow = pressure line; yellow arrow = return line). Carefully check the rack and lines first, prior to spending your money on a rebuilt rack. The most common leakage point for the rack is out the ends. If you cut open your tie rod boot and a lot of power steering fluid starts flowing out, then chances are that the seals in the ends of your rack are worn, and it needs to be rebuilt or replaced. Unfortunately, there are no individual repair parts available for you to fix the rack yourself--it must be sent back to the manufacturer.

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Comments and Suggestions:
Buzzard Comments: Do you know if a rear schock off of a 996 turbo will fit on a 2000 996 cabriolet
May 11, 2013
  Followup from the Pelican Staff: Give our parts specialists a call: 1-888-280-7799 They will help you find the right shocks. - Nick at Pelican Parts  

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