A Forester Owner's Guide to the 2009-2018 Rear Suspension Trailing Arm
Hearing clunks from the rear? Your Forester's trailing arms might be the cause.
- A clunking noise from the rear over bumps is the most common sign of a failed trailing arm bushing.
- Expect bolts to be seized with rust; this can significantly increase repair time and difficulty.
- A four-wheel alignment is required immediately after replacement to prevent unsafe handling and tire damage.
- Aftermarket brands like Moog are well-regarded by owners, while Dorman offers a budget-friendly alternative.
Is Your Forester Making a Clunking Sound?
The most common reason to replace a trailing arm on a 2009-2018 Forester isn't because the arm itself breaks, but because its rubber bushings wear out. Over time, these bushings crack and degrade from constant movement, heat, and exposure to road salt. When the bushings fail, they allow for excess movement, which can cause a variety of symptoms.
Top 4 Signs of a Failing Trailing Arm:
- Clunking or Rattling Noises: This is the most frequent complaint. You may hear a clunk or thud from the rear when you go over bumps, accelerate, or brake. This sound is often the metal arm making contact with its bracket now that the cushioning bushing has failed.
- Unstable or Wandering Rear End: The vehicle might feel like it's swaying or won't drive in a straight line without constant steering correction. This loss of stability happens because the worn bushings allow the rear wheel's alignment to change unexpectedly.
- Uneven Tire Wear: Bad trailing arm bushings can cause the rear alignment to fall out of specification. This leads to rapid and uneven tire wear, sometimes appearing as scalloped or cupped patterns on the tread.
- Loose Steering Sensation: Even though the problem is in the rear, it can feel like the steering is loose. This is because you are subconsciously making small corrections to compensate for the rear wheels not tracking properly.
Known Issues: Rust and Seized Bolts
While no specific recalls exist for the rear trailing arms on the 2009-2018 Forester, rust is a major concern for all Subaru suspension components, especially in salt-belt regions. The bolts that hold the trailing arm in place, particularly the long bolt through the wheel knuckle, are notorious for seizing with rust. This can make replacement significantly more difficult, often requiring cutting tools. Always apply a quality penetrating oil to all bolts well before attempting removal.
Choosing the Right Aftermarket Trailing Arm
When shopping for a new aftermarket trailing arm, you'll find several brands. They generally fall into different quality tiers. The entire assembly, which includes new bushings, is almost always replaced.
Premium Brands (Moog, Delphi)
These brands are often considered higher-quality aftermarket options. Forum discussions among Subaru owners frequently mention Moog as a reliable choice that holds up well. These parts are engineered to meet or exceed original equipment (OE) specifications and often feature durable coatings and high-quality rubber bushings. They are a solid choice for owners who plan to keep their Forester for a long time.
Mid-Grade Brands (Mevotech)
Mevotech often provides a good balance between price and quality. They may offer different product lines, such as a standard replacement and a more durable "Supreme" version. For a daily-driven Forester, Mevotech can be a cost-effective solution that restores original performance.
Economy Brands (Dorman)
Dorman is known for providing affordable, direct-fit replacements. While they are a budget-friendly option, some users report that their longevity may not match that of more premium brands. A Dorman arm can be a good choice if you're on a tight budget or don't plan on keeping the vehicle for many more years.
Pro Tip: Regardless of the brand you choose, it's highly recommended to replace trailing arms in pairs (both left and right sides). This ensures balanced handling and predictable performance from your rear suspension.
Cost to Replace a Subaru Forester Trailing Arm
| Part Type | Estimated Cost (Part Only) |
|---|---|
| New Aftermarket | $56 - $295 |
| New OEM | $95 - $220 |
| Shop Labor | $180 - $450 |
Costs are estimates and can vary based on your location, vehicle, and the specific parts chosen. Labor costs can increase significantly if bolts are seized due to rust.
Frequently Asked Questions
Do I need a wheel alignment after replacing the trailing arm?
Yes, absolutely. Replacing a trailing arm will alter the rear suspension geometry. A four-wheel alignment is mandatory to ensure proper handling, prevent premature tire wear, and ensure the vehicle drives straight.
Can I just replace the bushings instead of the whole arm?
While bushings are available separately, replacing them requires a hydraulic press and specialized tools. For most DIY mechanics and even many shops, it is faster and more cost-effective to replace the entire trailing arm assembly, which comes with new bushings already installed.
Should I replace any other parts at the same time?
It's a good idea to inspect the other rear suspension components, such as the sway bar end links and other control arms. Given the high likelihood of rust, you should consider having new trailing arm mounting bolts on hand, as the old ones may need to be cut off.
Is the left trailing arm the same as the right one?
No, the left (driver side) and right (passenger side) trailing arms are not interchangeable. They are designed specifically for their respective sides of the vehicle. Ensure you order the correct part for the side you are replacing.
Helpful Videos
Technical Specifications
OEM Part Numbers: 20250FG010 20250FG000 20250AJ07A 20250FJ000 20250FJ001
The trailing arm for the 2009-2018 Subaru Forester is a stamped steel component that connects the rear knuckle to the chassis. It is side-specific (left and right) and comes with pre-installed rubber bushings at both pivot points. Some aftermarket versions may offer adjustability for camber or toe.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Subaru Forester:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your Forester Making a Clunking Sound?
- Top 4 Signs of a Failing Trailing Arm:
- Known Issues: Rust and Seized Bolts
- Choosing the Right Aftermarket Trailing Arm
- Premium Brands (Moog, Delphi)
- Mid-Grade Brands (Mevotech)
- Economy Brands (Dorman)
- Cost to Replace a Subaru Forester Trailing Arm
- Frequently Asked Questions
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