1985 Porsche 911 Bilstein Sport Part Numbers: The Complete Guide

If you own a 1985 Porsche 911 and are looking to upgrade or replace the shocks, Bilstein Sport dampers are a popular choice. These monotube gas shocks deliver excellent performance for street and light track use. However, finding the exact part numbers for a 1985 model can be confusing because Porsche used different suspension setups across the G-body range (1974–1989). This guide will help you identify the correct Bilstein Sport part numbers for your 1985 911, whether it's a Carrera, Turbo, or Targa.

Understanding the 1985 Porsche 911 Suspension

The 1985 911 (G-series) came with two main suspension configurations: standard and M030 sport suspension. The standard setup uses lower spring rates and softer damping, while the M030 package features stiffer springs and firmer shocks. Bilstein Sport dampers are designed to work with both, but the part numbers differ slightly depending on whether your car has adjustable perches (height-adjustable spring seats) or fixed perches.

Front Shocks

For the front, the Bilstein Sport part numbers for the 1985 911 are:

• Without adjustable perches: P/N 24-000333
• With adjustable perches: P/N 24-000334

"Without adjustable perches" means the shock has a fixed lower spring seat. This is the most common setup on standard 911s. The "with adjustable perches" version allows you to raise or lower the front ride height by turning the spring seat. Both versions are identical in damping—they use the same monotube valve design. The only difference is the lower mounting.

How to Check Your Car

To determine whether you have adjustable perches, look at the front strut. On a car with adjustable perches, there is a threaded ring that can be turned to move the spring seat up or down. On fixed-perch cars, the spring seat is welded or pressed onto the strut tube.

Rear Shocks

For the rear, the Bilstein Sport part numbers depend on the body style (coupe, Targa, or Cabriolet) and whether the car has the optional thicker rear sway bar. The general part numbers are:

• Coupe without thicker sway bar: P/N 24-000335
• Coupe with thicker sway bar (M030 or aftermarket): P/N 24-000336
• Targa/Cabriolet without thicker sway bar: P/N 24-000337
• Targa/Cabriolet with thicker sway bar: P/N 24-000338

Note: The rear shock for Targa/Cabriolet is different because those chassis have additional bracing that changes the damper’s mounting dimensions. If you have a Cabriolet, you must use the Targa/Cabriolet version—do not install coupe shocks on a Cabriolet, as they will not fit properly.

Differences Between Bilstein Sport and Other Bilstein Models

Bilstein offers several lines for the 911: Touring (B6), Sport (B8), and HD (B4). For the 1985 911, the Sport (B8) is the most performance-oriented while still being daily-drivable. The B6 Touring is a bit softer, and the B4 HD is designed for standard ride height. If you are lowering your car (even slightly), the B8 Sport is recommended because it has a shorter body to prevent bottoming out.

Valving Characteristics

The Bilstein Sport uses digressive valving: firm on slow inputs (cornering) but compliant on fast hits (bumps). This provides excellent body control without harshness. Many enthusiasts consider it the best all-around shock for street and occasional track use.

Installation Considerations

Front Strut Assembly

Replacing the front shocks requires removing the entire strut assembly from the car. The Bilstein Sport front struts come as a complete insert that slides into the existing strut housing. You will need to transfer the spring perch, bump stop, and dust boot from your old strut to the new one. If your car has adjustable perches, the new Bilstein includes the threaded spring seat and adjustment ring. Some users prefer to reuse the original Porsche bump stops; Bilstein includes new bump stops in the box, but they are often stiffer than stock.

Rear Shock Replacement

The rear shocks are straightforward: unbolt the lower mount (through the trailing arm) and the upper mount (inside the wheel well). Use a jack to support the trailing arm before removing the old shock. The Bilstein Sport rear shocks are gas-charged, so they will extend on their own—compress them by hand or use a strap to install.

Needle Bearings and Bushings

When installing new Bilstein Sport shocks, inspect the upper and lower mounting bushings. If they are worn, replace them with genuine Porsche or high-quality aftermarket bushings. The front upper strut mounts often fail on older 911s, causing clunking noises. Replace these with new mounts from Porsche (part number 911.341.131.00 for the rubber mount, or use FK Automotive or Elephant Racing solid mounts for stiffer response).

Common Questions

Will Bilstein Sport Work with Stock Springs?

Yes. The Bilstein Sport dampers are designed to work with stock spring rates. However, if you lower the car significantly (more than 1 inch), you may need shorter springs to avoid coil bind. For a mild drop, stock springs with adjustable perches are fine.

Are Bilstein Sport Shocks Rebuildable?

Yes. Bilstein offers rebuild services through authorized dealers. Most owners run them for 100,000 miles before needing a rebuild. The Sport shocks are lifetime warranted to the original purchaser.

How Do I Confirm the Part Number?

Always verify the part number by looking at the label on the old shock or by contacting a Bilstein dealer with your VIN. Porsche changed suspension details during the model year, so a late-1985 car might have different requirements than an early-1985 car.

Final Recommendation

For a 1985 Porsche 911 that is used for street driving and occasional autocross or track days, the Bilstein Sport (B8) is an outstanding choice. Here is a quick cheat sheet:

• Front without adjustable perches: P/N 24-000333
• Front with adjustable perches: P/N 24-000334
• Rear coupe, standard sway bar: P/N 24-000335
• Rear coupe, thicker sway bar: P/N 24-000336
• Rear Targa/Cabriolet, standard sway bar: P/N 24-000337
• Rear Targa/Cabriolet, thicker sway bar: P/N 24-000338

If you are unsure about your car's configuration, measure the diameter of the rear sway bar. The standard bar is 18mm; the thicker bar (M030) is 21mm. Also, check for the presence of adjustable perches on the front struts. When in doubt, purchase the non-adjustable perch version for the front, as it is simpler and more common. For the rear, buy the version that matches your body style and sway bar. Installation is a moderate DIY job if you have basic mechanical skills, but be sure to torque all bolts to spec and get a professional alignment afterward.