1999-2002 Subaru Forester Strut Guide: Noises, Leaks, and the Self-Leveling Trap

Symptoms of a Failing Strut

Worn struts degrade gradually, so you might not notice the change right away. However, there are specific signs that indicate it's time for a replacement. Ignoring them can lead to poor handling, increased stopping distances, and accelerated wear on your tires and other suspension parts.

Noises and Vibrations

• Clunking or Knocking: A common symptom is a clunking or knocking sound when driving over bumps, potholes, or uneven pavement. This is often caused by metal-to-metal contact inside a worn strut or from failing strut mounts.
• Steering Wheel Vibrations: While many issues can cause vibrations, worn struts can contribute to a shaky steering wheel, especially on rough roads.

Poor Ride Quality and Handling

• Bouncy Ride: If your Forester feels like it's bouncing excessively after hitting a bump, the struts are no longer effectively dampening the spring's movement. This is one of the most classic signs of failure.
• Nose-Diving and Squatting: When you brake hard, does the front end of the car dip excessively? Or does the rear end squat down when you accelerate? This indicates the struts are too weak to manage the vehicle's weight transfer.
• Body Roll or Sway: A feeling that the vehicle is unstable, swaying, or rolling excessively during turns is a sign that the struts can no longer keep the body level.

Visual Signs

• Leaking Fluid: Struts are filled with hydraulic fluid. If you see oily, wet residue on the outside of the strut body, the internal seal has failed and the strut must be replaced.
• Uneven Tire Wear: Worn struts can cause a specific type of uneven tire wear called "cupping" or "scalloping." This appears as high and low spots along the tire's tread because the tire is bouncing as it rotates.

The Self-Leveling Rear Suspension Trap

One of the most important things to know when buying struts for a 1999-2002 Forester is whether your vehicle has the optional self-leveling rear suspension (SLS). This system was typically found on higher trim levels like the 'S' model.

• What it is: The SLS system is entirely contained within the rear struts. It uses the vehicle's motion to pump itself up to maintain a level ride height, even when carrying heavy loads. It is not an electronic or air-ride system controlled from the dashboard.
• How to Identify It: The easiest way to check is to look at the rear struts. A self-leveling strut will have a large, distinct canister attached to the side of the main strut body. A standard strut will just be a straight tube.
• The Problem: OEM self-leveling struts are extremely expensive to replace. Because of the high cost, many owners choose to convert to a standard, non-SLS setup.
• Conversion: To convert from SLS to standard suspension, you MUST replace both the struts and the coil springs as a matched pair. Using standard struts with SLS springs (or vice-versa) will result in an incorrect ride height and poor handling. Many aftermarket companies sell conversion kits that include the correct struts and springs.

Buying a Used 1999-2002 Forester Strut

A low-mileage used OEM strut can be a great value, but careful inspection is key. Struts are a wear item, so buying a high-mileage used part is a gamble.

• Physical Inspection: Look for any signs of fluid leaks on the strut body—any wetness or thick grime is a red flag. Check that the strut shaft is straight and not bent. Inspect the dust boot for tears and the bump stop for deterioration. If it's a complete assembly, check the coil spring for any cracks or heavy corrosion.
• Mileage: Try to find struts from a vehicle with under 100,000 miles. Struts can begin to show significant wear beyond this point.
• Compatibility Check: This is the most critical step. You must know:
  1. Position: Is it for the Front Left (driver), Front Right (passenger), Rear Left, or Rear Right? They are not interchangeable.
  2. Suspension Type (Rear Only): Is it a standard strut or a self-leveling strut? As detailed above, they are not compatible. A used standard strut assembly (with its matching spring) is a common part to buy for an SLS-to-standard conversion.
• Used OEM vs. New Aftermarket: A low-mileage used OEM strut assembly often provides better ride quality and durability than a cheap, new, complete "quick-strut" assembly. The valving and spring rates on OEM parts are specifically tuned for the Forester, while some budget aftermarket parts can result in a harsh or floaty ride.

Replacement Information

Replacing struts is a job that can be done by a skilled DIY mechanic, but it involves safety risks. If you are not comfortable compressing coil springs, it is safer to buy a complete strut assembly (with the spring and mount already installed) or have a professional perform the work.

Related Parts to Replace

When replacing struts, it's wise to inspect and often replace the following parts at the same time:

• Strut Mounts (Top Hats): These rubber and metal mounts at the top of the strut can wear out, causing noise and alignment issues.
• Sway Bar End Links: These connect the sway bar to the strut or control arm and often get worn or broken.
• Control Arm Bushings: Inspect all rubber bushings for cracks and wear.

Special Procedures & Torque Specs

A professional wheel alignment is required after replacing struts to ensure proper handling and prevent premature tire wear. When tightening suspension bolts, it's best practice to have the vehicle's full weight on the suspension (on the ground or on ramps) to avoid binding the bushings.

Cost Comparison

Prices can vary significantly based on brand and whether you buy a bare strut or a complete assembly. Labor for replacement is typically 1-2 hours per corner.

Part Number Reference

The following part numbers are for reference. Always verify fitment with the seller for your specific vehicle position and suspension type.

• OEM (Subaru): 20310FC000, 20310FC010, 20310FC011, 20310FC020, 20310FC030, 20310FC031, 20310FC040, 20310FC050, 20310FC051, 20311FC120, 20311FC140
• Aftermarket (KYB): 334189 (Front Right), 334190 (Front Left), 334191 (Rear)
• Aftermarket (Monroe): 71410 (Rear), 71464, 71463
• Aftermarket (Gabriel): G56545, G56543

Frequently Asked Questions