2008 Subaru Legacy Parts List: Rear Suspension Components

The rear suspension of the 2008 Subaru Legacy is a multi-link independent setup designed for a balance of ride comfort and handling. Whether you're planning a repair, upgrade, or just want to understand what's back there, knowing the specific parts and their functions is essential. This guide covers every major component in the rear suspension system, including common wear items and practical tips for replacement.

Key Rear Suspension Components

1. Rear Strut Assembly

Each rear wheel is supported by a strut assembly that combines a shock absorber and coil spring. The 2008 Legacy uses a MacPherson strut design in the rear. The assembly includes:

• Strut housing (metal casing)
• Piston rod and internal valving
• Coil spring (variable rate depending on trim)
• Upper strut mount (with bearing for steering)
• Bump stop and dust boot

Common signs of wear: leaking fluid, bouncy ride, clunking noises over bumps.

2. Lower Control Arm (LCA)

The rear lower control arm connects the wheel hub to the subframe. It controls lateral and longitudinal movement. It has two bushings—one at the subframe side and one at the knuckle side. The arm itself is a stamped steel piece. On some trims (like the GT), aluminum arms were used. Check for cracked or collapsed bushings, which cause vague steering or rear-end sway.

3. Upper Control Arm (UCA)

Also known as the rear upper arm, this controls camber angle. It mounts between the knuckle and the subframe with a ball joint at the knuckle end and a bushing at the subframe. The ball joint is a common failure point, leading to clunking and misalignment. Aftermarket adjustable upper control arms are popular for camber correction if the car is lowered.

4. Toe Control Arm (Lateral Link)

The rear toe control arm (or lateral link) attaches from the subframe to the knuckle. It adjusts toe angle and keeps the rear wheels parallel. The inner bushing often wears out, causing play and uneven tire wear. A pair of toe arms is used (one per side).

5. Rear Knuckle / Spindle

The knuckle is the cast aluminum or steel part that holds the wheel bearing and hub, and connects all the control arms and the strut. The wheel bearing is pressed into the knuckle. A failing bearing makes a humming noise that changes with speed. Replacing the bearing requires pressing out the old one and pressing in a new one.

6. Sway Bar (Stabilizer Bar) and Links

The rear sway bar reduces body roll during cornering. It connects to the left and right lower control arms via end links. The sway bar is mounted to the subframe with rubber or polyurethane bushings. Worn end links cause rattling over bumps. The bushings can crack, leading to clunking. Upgrading to thicker sway bar and polyurethane bushings stiffens the rear end for better handling.

7. Springs and Coilovers

While the strut includes the spring, some owners opt to replace just the springs with aftermarket ones (e.g., lowering springs for improved stance). For adjustable ride height and damping, coilover kits are available. Be aware that lowering more than 1.5 inches may require camber correction parts.

8. Subframe and Mounts

The rear subframe holds the differential and suspension arms. It is attached to the body with four large rubber mounts. These mounts can sag or tear, causing excessive vibration and noise. Upgraded polyurethane subframe bushings are common for stiffer feel.

Disassembly and Replacement Tips

• Always loosen and torque bolts with the suspension loaded (car on the ground) to avoid bushing binding.
• When replacing struts, consider replacing the upper mounts and bump stops at the same time.
• Use OEM or equivalent quality parts for bushings and ball joints to ensure longevity.
• For the wheel bearing, a shop press or specialized tool is required. If you don't have access, hiring a mechanic for this step may be wise.
• After any suspension work, a professional alignment is mandatory to set camber and toe to spec.

Common Issues with 2008 Legacy Rear Suspension

• Strut failure: Leaking struts are common after 80,000 miles. Replace with KYB or OEM struts.
• Upper control arm ball joint: The dust boot tears, dirt enters, and the joint fails. Inspect during tire rotations.
• Sway bar end links: Prone to wear. Polyurethane replacement links are more durable.
• Wheel bearing hum: Usually starts around 100,000 miles. Replace bearing and hub assembly for ease.
• Bushing cracks: Lower control arm bushings and subframe bushings harden and crack over time. Poly replacements improve response.

Aftermarket Options

If you're upgrading for performance or lowering, consider:

• Adjustable upper control arms (e.g., from Whiteline, Cusco) for camber adjustment.
• Rear sway bar (20mm or 22mm) with heavy-duty end links.
• Lower control arm bushing inserts (like Whiteline KDT903) to reduce deflection without replacing entire arm.
• Coilovers from brands like BC Racing, Tein, or KW for adjustable damping and height.

Replacement Part Number Reference

Here are some common OEM part numbers for the 2008 Legacy rear suspension (double-check with your VIN):

• Rear strut assembly (right): 20310AG37A
• Rear strut assembly (left): 20310AG38A
• Upper strut mount: 20320AG01A
• Lower control arm: 20201AG26A (right), 20201AG27A (left)
• Upper control arm: 20260AG29A (right), 20260AG30A (left)
• Toe control arm: 20280AG22A (right), 20280AG23A (left)
• Sway bar end link: 20470AG30A
• Wheel bearing: 28473AG00A (bearing only), 28473AG01A (hub unit)

These numbers can be used to cross-reference aftermarket parts at auto parts stores or online parts catalogs.

Final Recommendation

For a 2008 Subaru Legacy with high mileage (over 100k), focus on replacing the struts, upper control arm ball joints, and sway bar end links first. This restores ride quality and eliminates noises. Use OEM or premium aftermarket (KYB for struts, Moog for control arms) to ensure fit and durability. If you plan to lower the car, invest in adjustable upper control arms to keep the rear camber within spec. Always torque all fasteners to factory specifications and get a four-wheel alignment after completion. This approach keeps your Legacy handling safely and comfortably for many more miles.