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If your Subaru Legacy is showing wandering, uneven tire wear, or a loose rear feel, replacing worn rear control arms can restore safe handling and alignment. The right rear control arm improves chassis stability, reduces vibration, and helps keep suspension geometry within factory tolerances for better steering response and tire life.This guide covers our shortlisted rear control arms for the Subaru Legacy and explains the key criteria used to evaluate each option. We focus on fitment, bushing and joint durability, and how the parts affect alignment and ride quality to help you pick the best replacement for your needs.
Looking for other parts? See all Subaru Legacy parts & accessories.
Top Picks at a Glance
| Best Overall The best all-around choice for most situations | MOOG RK100124 Rear Lower Forward Suspension Control Arm and Ball Joint Assembly |  |
| Best Quality Built to a higher standard if you want something more solid | Whiteline KTA124 Rear Adjustable Control Arm Assembly |  |
| Best Value The sweet spot between price and what you get | TRQ Rear Lower Rearward Control Arm Set (2-piece) |  |
| Best Budget The cheapest option that still gets the job done reliably | MOOG RK643085 Rear Lower Suspension Control Arm |  |
| Highest Rated A top-rated pick with lots of positive feedback | Metrix Premium Chassis Parts Rear Upper Control Arm Kit with Ball Joints (Left & Right) |  |
| Most Popular A crowd favorite that many people choose with confidence | Detroit Axle Pair Rear Lower Control Arms (Adjustable) for Subaru Legacy and Related Models |  |
| Best Seller A high-volume bestseller chosen again and again | Metrix Premium Chassis Parts Rear Lower Forward Control Arm with Ball Joint, 2‑Piece Kit |  |
1. MOOG RK100124 Rear Lower Forward Suspension Control Arm and Ball Joint Assembly
| Fit Type | Vehicle Specific Fit |
|---|---|
| Auto Part Position | Rear |
| Material Type | Alloy Steel, Iron |
| Unit Count | 1 Count |
This MOOG RK100124 is a rear lower forward control arm with an integrated ball joint built as a vehicle-specific replacement part. It restores suspension geometry and helps correct alignment and tire wear that come from worn rear arm bushings or joints. MOOG emphasizes structural strength and added corrosion protection, and the alloy steel and iron construction should hold up to everyday driving and road impacts. The part is intended for direct-fit installation, so it is typically used as a one-for-one replacement during a rear suspension repair or while addressing handling issues like pull, looseness, or unusual noises. Practical benefits include simpler installation compared with aftermarket universal arms, restored steering feel, and longer service life from heat-treated components and coatings. Limitations are that this unit is a single-side, vehicle-specific replacement and does not include matching hardware or multiple arms, so budget-conscious buyers may need to purchase additional pieces for full-axle work.
Best for: Buyers seeking a dependable, factory-replacement style rear control arm to restore handling and alignment on an aging Subaru who value durability and straightforward installation.
Less Ideal for: Drivers wanting adjustable or performance-tuned rear suspension components or shoppers who need a full set or hardware included in one purchase.
- Direct-fit, vehicle-specific design for straightforward replacement
- Integrated ball joint simplifies parts matching and installation
- Heat-treated alloy steel and iron construction for strength
- Coatings applied to inhibit corrosion and extend service life
- Sold as a single unit so replacing both sides requires separate purchases
- Does not include additional mounting hardware or alignment parts
Verdict: Choose this MOOG control arm when you want a durable, direct-fit rear replacement that restores handling and reduces alignment headaches on your Subaru.
2. Whiteline KTA124 Rear Adjustable Control Arm Assembly
| Fit Type | Vehicle Specific Fit |
|---|---|
| Auto Part Position | Left |
| Auto Part Orientation | Front |
| Material Type | Polyurethane on Bushings |
The Whiteline KTA124 rear control arm assembly is a complete four-arm kit built to give tuners more control over rear camber, toe, and track settings. Each arm uses low-compliance polyurethane bushings and left-right thread turnbuckle adjusters so you can make on-car corrections without removing components. In practice this yields a firmer, more direct connection between the chassis and rear suspension, which sharpens turn-in and makes high-speed or track driving more predictable. Installation is typical for suspension arms and may require alignment after adjustment; the low-compliance bushings improve responsiveness but can transmit more road noise and vibration than softer bushings. These arms are aimed at drivers who plan to tune rear geometry for better handling rather than for comfort. They are durable and clearly focused on performance, but expect a firmer ride and the need for professional alignment when changing settings significantly.
Best for: Drivers focused on improving rear-end handling and steering response who plan to tune suspension geometry for spirited driving or occasional track use.
Less Ideal for: Buyers seeking a softer, comfort-oriented rear suspension or those who prefer a no-adjustment, maintenance-free replacement.
- Complete four-arm kit for full rear geometry adjustment
- Adjustable turnbuckle design allows on-car left-right adjustments
- Low-compliance polyurethane bushings improve steering precision and suspension feedback
- Designed to increase range and accuracy of camber and toe corrections
- Stiffer bushings can increase road noise and vibration
- May require professional alignment after installation to realize benefits
Verdict: Choose the KTA124 if you want a complete, adjustable rear control arm kit that tightens rear suspension response and gives precise on-car camber and toe tuning for better handling.
3. TRQ Rear Lower Rearward Control Arm Set (2-piece)
| Manufacturer Part Number | PSA37997 |
|---|---|
| Included Components | 2 Piece Control Arm Set |
| OEM Equivalent Part Number | 20250AE01A |
| Fit Type | Vehicle Specific Fit |
| Auto Part Position | Rear Lower |
This TRQ rear lower rearward control arm set replaces the factory rear lower arms on compatible Subaru Legacy, Outback, and Baja models and comes as a matched pair for driver and passenger sides. It is intended as a direct-fit replacement so installation is straightforward for a DIYer or a shop using standard suspension tools, and TRQ provides step-by-step videos to guide the process. The arms are preassembled to mirror factory geometry, which helps restore rear suspension alignment and improve ride stability and tire wear after worn arms are removed. Because the kit is vehicle-specific it simplifies part selection and reduces the chance of fitment issues. Limitations are typical of aftermarket control arms: performance gains beyond restoring factory handling are limited, and installation still requires basic alignment afterward. The set is best when you need a like-for-like replacement to bring rear suspension back to factory-spec without upgrading to performance components.
Best for: Buyers who want a practical, reliable direct-replacement to restore rear suspension geometry and stability on compatible Subaru models with minimal fuss and clear installation guidance.
Less Ideal for: Drivers seeking upgraded performance suspension components or custom handling improvements should consider performance-oriented control arms instead.
- Matched two-piece kit for driver and passenger rear lower arms
- Vehicle-specific fit reduces fitment guesswork
- Preassembled components simplify installation and mirror factory geometry
- Manufacturer provides installation videos to assist DIY repairs
- Designed as a direct replacement so it does not offer enhanced performance over factory parts
Verdict: Choose this matched pair when you need a straightforward, vehicle-specific replacement to restore factory rear suspension geometry on supported Subaru models.
4. MOOG RK643085 Rear Lower Suspension Control Arm
| Fit Type | Vehicle Specific Fit |
|---|---|
| Auto Part Position | Rear Lower |
| Material Type | Alloy Steel |
The MOOG RK643085 rear lower control arm is a direct-fit replacement intended to restore proper suspension geometry and ride quality on compatible Subaru Legacy, Outback, and Baja models. It installs in the rear lower position and is engineered from alloy steel with added corrosion protection and heat-treated structural areas to resist impact and repetitive loads. In everyday use this part replaces worn or damaged control arms to reduce steering play, stop uneven inner tire wear, and eliminate clunks over rough roads. MOOG emphasizes precise engineering for easier installation and serviceability, which helps DIYers and shops complete the job without fabrication. The main limitations are that fitment is vehicle-specific, so you must confirm year and model compatibility, and it is a single-arm replacement so front or both-side wear may require additional parts for a complete alignment. For budget-focused buyers seeking a durable, factory-quality replacement that simplifies installation, this is a practical choice for maintaining Subaru rear suspension performance.
Best for: Buyers replacing a worn rear lower control arm on a Subaru who want a durable, factory-quality direct-fit part that is straightforward to install on a budget.
Less Ideal for: Buyers looking for adjustable performance suspension components or multi-vehicle fitment should consider other options.
- Vehicle-specific direct-fit design simplifies installation and avoids modification
- Alloy steel construction with heat-treated areas for improved structural strength
- Corrosion-resistant coatings on studs increase service life
- Designed to restore suspension geometry and steering stability
- Manufactured by a well-known chassis specialist with focus on durability
- Compatibility limited to specific Subaru models and model years so verify fitment before purchase
Verdict: A durable, budget-friendly direct-fit rear lower control arm that restores handling and is easy to install on compatible Subaru models.
5. Metrix Premium Chassis Parts Rear Upper Control Arm Kit with Ball Joints (Left & Right)
| Fit Type | Vehicle Specific Fit |
|---|---|
| Auto Part Position | Rear Upper |
| Material Type | Sheet Metal |
| Unit Count | 2 Count |
| Manufacturer Warranty Description | 3 Year / 36,000 miles Limited Warranty |
This Metrix Premium kit replaces both rear upper control arms and includes pre-greased ball joint assemblies for the left and right sides. Designed as vehicle-specific fitments for Subaru Impreza (2012-2022 variants listed), WRX (2015-2021), WRX STI (2015-2021), and Legacy (2015-2019), the parts are sheet metal constructions finished in a corrosion-resistant coating and intended for direct installation. The greasable design and pre-lubrication simplify routine maintenance and should extend service life compared with non-greasable aftermarket arms. Metrix highlights factory-quality dimensions and certification to industry quality standards, which supports consistent handling and alignment when installed and followed by a wheel alignment check. Expect a straightforward swap for a competent DIYer or professional, though alignment and inspection of associated rear suspension components are required after replacement. These are focused replacements rather than performance upgrades, so drivers seeking lighter-weight or sport-tuned suspension parts should look elsewhere.
Best for: Buyers who prioritize long-term dependability and a like-for-like replacement to restore factory handling on their Subaru’s rear suspension.
Less Ideal for: Drivers looking for performance-oriented, lightweight, or race-tuned control arms should consider aftermarket performance parts instead.
- Vehicle-specific design for direct fit to listed Subaru rear upper locations
- Includes both left and right assemblies with pre-greased ball joints for easier installation and initial service life
- Corrosion-resistant coating and certified manufacturing standards aiming for consistent durability
- Greasable fittings allow periodic maintenance to extend component life
- Sheet metal construction may not be as light as aluminum performance arms
Verdict: A durable, factory-style replacement rear upper control arm kit that restores reliable rear suspension performance for Subaru models needing dependable serviceable parts.
6. Detroit Axle Pair Rear Lower Control Arms (Adjustable) for Subaru Legacy and Related Models
| Fit Type | Vehicle Specific Fit |
|---|---|
| Auto Part Position | Rear Lower |
| Material | Alloy Steel |
| Adjustability | ±2° Camber, 1.5° Fixed Toe |
These Detroit Axle rear lower control arms replace the factory rearward lower links with an adjustable aftermarket unit that lets you dial in up to plus or minus 2 degrees of camber and a fixed 1.5 degree toe correction. Sold as a passenger and driver side pair, the assemblies are alloy steel with a polished exterior and are intended as direct-fit, vehicle-specific replacements for Subaru Legacy and several related models. In use they provide a straightforward way to restore rear suspension geometry after worn arms or to fine-tune alignment on lowered setups without modifying the factory subframe. Notable features include the adjustability for camber, factory-style mounting points, and a claimed 10-year warranty. Expect a heavier, more robust feel than stock and a fit-and-forget installation if the included parts match your model year. The main limitations are that they are vehicle-specific so you must confirm exact fitment, and the fixed toe value limits more extensive alignment adjustments; you may still need a shop alignment after installation.
Best for: Buyers who want a durable, vehicle-specific replacement that restores or allows minor camber tuning on Subaru Legacy rear suspension while leaning on community-tested choices.
Less Ideal for: Drivers seeking fully adjustable toe settings, custom multi-vehicle fitment, or a lightweight race-focused control arm should look at other options.
- Adjustable camber up to plus or minus 2 degrees for fine alignment correction
- Vehicle-specific direct-fit design simplifies installation
- Alloy steel construction for greater durability compared with typical stamped arms
- Sold as a matched passenger and driver side pair for consistent rear geometry
- Toe is fixed at 1.5 degrees which limits full alignment flexibility
- Fitment covers specific Subaru model years so incorrect selection will not fit
Verdict: Choose these Detroit Axle rear lower control arms if you want a robust, vehicle-specific replacement that restores rear geometry and allows minor camber tuning for Subaru Legacy owners prioritizing proven reliability.
7. Metrix Premium Chassis Parts Rear Lower Forward Control Arm with Ball Joint, 2‑Piece Kit
| Fit Type | Vehicle Specific Fit |
|---|---|
| Auto Part Position | Rear Lower |
| Material Type | Carbon Steel |
| Manufacturer Warranty Description | 3 Year / 36,000 miles warranty |
| Quantity in box | 2 |
This Metrix Premium kit supplies two rear lower forward control arms with preinstalled ball joints intended as direct replacements for late-model Subaru platforms and related vehicles. Made from carbon steel with a corrosion-resistant coating and greasable fittings, the arms aim to restore rear suspension geometry and steering stability after wear or damage. Install is typical for control-arm replacement: lift the vehicle, remove the wheel, swap the assemblies, and then have a wheel alignment performed. The kit includes cotter pins and is factory-style in fit, so it suits DIYers comfortable with suspension work and professional shops alike. Metrix highlights IATF 16949 and ISO 9001 production standards and backs the parts with a 3 year/36,000 mile warranty, which should reassure buyers who prioritize low risk and known-quality sourcing. Note that these are vehicle-specific fitment parts, so confirm exact model-year compatibility before purchase and plan for a post-install alignment; performance upgrades or nonstandard suspension setups may require different components.
Best for: Buyers looking for a reliable, factory-quality rear control arm replacement who prioritize correct fitment, corrosion resistance, and warranty-backed parts to minimize installation risk.
Less Ideal for: Drivers seeking aftermarket performance upgrades, modified suspension setups, or adjustable control arms for tuning should consider performance-oriented alternatives instead.
- Direct-fit, vehicle-specific design simplifies installation and helps restore correct suspension geometry
- Integrated ball joints and included cotter pins reduce parts sourcing and assembly time
- Carbon steel construction with cataphoresis-style coating improves corrosion resistance for longer service life
- Greasable design allows periodic maintenance to extend component life
- Backed by manufacturing certifications and a 3 year/36,000 mile warranty for added buyer confidence
- Designed as a factory-style replacement so it does not provide performance improvements for sport or track tuning
Verdict: A dependable, warranty-backed factory-style rear lower control arm kit that restores correct rear suspension geometry with minimal risk for Subaru owners seeking a direct replacement.
Choosing the Right Subaru Legacy Rear Control Arm: Key Factors to Consider
Fitment and Mounting Points
Correct fitment is essential because rear control arms must match the Subaru Legacy's rear subframe and trailing arm mounting pattern to maintain suspension geometry. Even small differences in bushing spacing or bolt hole diameter can alter caster and toe characteristics, leading to accelerated tire wear or handling quirks.
When evaluating fitment, check whether the arm is designed for your Legacy's production years and whether it uses OE-style pressed-in bushings or a serviceable insert. Parts that explicitly match factory mounting points reduce the risk of requiring additional modification or specialized hardware during installation.
Bushing Type and Durability
Bushings control how loads transfer between the control arm and chassis, so their material and design affect noise, vibration, and longevity. Rubber bushings provide quieter ride quality at the expense of quicker wear under heavy loads, while polyurethane or multi-piece designs resist deformation but can transmit more road noise.
For the Legacy, prioritize bushings that balance durability with NVH (noise, vibration, harshness) expectations. Consider whether the bushings are replaceable independently from the arm; replaceable bushings can reduce long-term ownership cost and simplify future repairs.
Ball Joint Quality and Serviceability
Some rear control arms include integrated ball joints while others rely solely on bushings. When a ball joint is present, its sealing, grease retention, and stud hardness affect longevity and steering precision. A poorly sealed ball joint can allow moisture and grit to enter, accelerating wear and risking failure.
Serviceable or greasable joints offer a maintenance advantage for owners who perform routine chassis lubrication. If the arm's ball joint is non-serviceable, plan for replacement of the entire arm when the joint shows wear.
Corrosion Protection and Materials
Subaru Legacy rear suspension components are exposed to road salt and water, so corrosion protection directly influences service life. Control arms made from stamped steel, cast aluminum, or forged alloys each behave differently when it comes to corrosion and fatigue.
Look for coatings such as e-coat, powder coat, or zinc plating and consider whether the design minimizes water traps. Better corrosion protection reduces the chance of seized bolts during maintenance and preserves structural integrity over time.
Impact on Alignment and Tire Wear
Rear control arms affect rear toe and camber targets, which are crucial for stable tracking and even tire wear on the Subaru Legacy. Arms that allow the suspension to move out of the factory geometry will cause alignment issues that cannot be fully corrected during a standard alignment session.
Choose arms that retain the vehicle's designed pivot points and that do not introduce additional play. If an arm offers adjustable positioning, ensure the range aligns with alignment equipment capabilities and that adjustments are repeatable for consistent tire wear results.
Installation Complexity and Tools Required
Installation difficulty influences both cost and the likelihood of proper fitment. Some rear control arms can be swapped using basic hand tools and a torque wrench, while others require press equipment to remove and install pressed-in bushings or specialized pullers for ball joints.
Assess whether the arm includes grease fittings, new mounting hardware, or instructions. If you plan DIY installation on a Legacy, factor in suspension preload, torque specifications, and whether an alignment will be needed immediately after replacement.
Signs Your Legacy Needs Rear Control Arm Service
Several common symptoms indicate rear control arm wear on a Subaru Legacy. You may notice a loose or wandering rear end at highway speeds, uneven tire wear across the rear tires, or a clunking noise when driving over bumps. Vibration or a feeling that the car does not track straight can also point to worn bushings or joints.
Addressing these signs early prevents secondary damage such as uneven tire wear or added stress to trailing arms and mounts. A careful inspection of bushings, ball joints, and mounting bolts will usually reveal whether the arm itself needs replacement or if the issue is isolated to a bushing or fastener.
- Loose rear feel or wandering
- Clicking or clunking over bumps
- Uneven rear tire wear
- Visible bushing cracks or torn rubber
How Replacement Arms Affect Ride and Handling
Replacing rear control arms can noticeably tighten the rear suspension feel and improve directional stability. Arms with stiffer bushings reduce lateral deflection, which sharpens handling but can increase transmitted road harshness. Conversely, arms with softer bushings preserve comfort but may allow more movement under load.
Consider the driving conditions you typically face in your Legacy. Owners who prioritize a compliant ride for daily commuting may prefer OE-style compliance, while those seeking firmer rear response for spirited driving might accept a slightly firmer ride in exchange for improved control.
- Stiffer bushings = firmer handling
- Softer bushings = quieter ride
- Serviceable components ease future repairs
Installation Tips for Subaru Legacy Rear Arms
Proper installation starts with using the correct torque values and ensuring the vehicle is at curb height or neutral ride height before final torquing of suspension fasteners. Tightening bolts with the suspension unloaded can preload bushings improperly, leading to premature wear or misalignment.
If the replacement arm has press-fit bushings, remove and install them with a hydraulic press or appropriate bushing tool. When a ball joint is involved, inspect the stud and taper for damage and use new cotter pins or locking hardware as specified. Always follow a proper alignment after installation to correct any toe or camber deviations.
- Torque fasteners at recommended ride height
- Use press tools for pressed-in bushings
- Perform alignment after installation
Maintenance Practices to Extend Arm Life
Routine inspections catch wear before it causes larger problems. Check bushings for cracking, separation, or excessive movement and look for play at ball joints by lifting the rear wheel and rocking the hub assembly. Keep mounting bolts clean and properly torqued to prevent movement-induced wear.
If your replacement arm includes grease fittings, perform periodic greasing as part of scheduled chassis maintenance. Addressing corrosion early with protective coatings on exposed metal and ensuring drainage holes are clear will help prolong service life in climates with road salt.
- Inspect bushings and joints every oil change
- Grease serviceable fittings periodically
- Treat exposed metal to prevent rust
When to Choose Full-Arm Replacement Versus Bushing Service
Deciding between replacing the entire rear control arm or servicing bushings depends on component condition, cost, and available tools. If the arm itself shows signs of bending, cracking, or significant corrosion, full-arm replacement is the safer choice. If only the bushings are worn and the arm is structurally sound, bushing replacement can be cost-effective.
Also consider labor and equipment: pressed-in bushing service often requires a press and special tools, while swapping the entire arm may be quicker and avoids potential issues if bushings are difficult to remove. Factor in the expected longevity and whether you want to return the suspension to like-new geometry.
- Replace entire arm if structural damage exists
- Bushing service for isolated wear and good arm condition
- Consider tool access and labor when choosing
Still looking for the perfect fit?
Select your Subaru Legacy configuration to see the most relevant Control Arms recommendations
How We Chose the Best Subaru Legacy Rear Control Arm
We prioritized rear control arms that meet three practical needs for Subaru Legacy owners: precise fitment to the vehicle mounting points, robust bushing and joint materials that resist wear, and designs that preserve or improve suspension geometry for reliable alignment. Our selection filters included compatibility with Legacy rear subframe and axle mounts, availability of serviceable bushings or factory-style press-in components, and ball joint specifications where applicable.Evaluation criteria emphasized material quality, corrosion protection, and tolerance to road loading because those factors determine long-term performance on the Legacy. We also considered ease of installation, including whether the arm accepts common replacement bushings or requires full-arm replacement, and whether alignment corrections typically stay within the range achievable at most alignment shops.We excluded options that lacked clear fitment information for the Subaru Legacy, products without measurable durability claims, and parts designed only for motorsport applications that would compromise everyday ride comfort. The final list balances reliability, longevity, and practical serviceability for typical Legacy owners.
Our full evaluation process is outlined in our review methodology.
FAQ
How do I tell if a rear control arm is bad on my Subaru Legacy?
Common indicators include clunking noises over bumps, excessive rear play or wandering, and uneven rear tire wear. Physically inspect bushings for cracks, separated rubber, or excessive movement and check for play at any integrated joints.
Can I replace rear control arm bushings without removing the arm?
Sometimes bushings can be pressed out while the arm is mounted, but many setups require arm removal and a press or bushing tool for safe removal and installation. Leaving the arm mounted can complicate access and increase the risk of improper bushing seating.
Will installing new rear control arms fix alignment issues on a Legacy?
New, properly fitting control arms restore the arm pivot points and reduce play that causes alignment drift. However, a full alignment is usually required after installation to set toe and camber to factory specifications.
Are greasable ball joints worth it for rear control arms?
Greasable joints allow periodic maintenance that can extend joint life, especially in harsh driving conditions. They do require routine attention, but for owners who maintain chassis lubrication, they offer a practical durability benefit.
How often should I inspect rear control arm bushings on a Subaru Legacy?
Inspect bushings during regular service intervals, such as every oil change or at least twice a year. More frequent checks are advisable if you drive on rough roads or in regions with heavy road salt exposure.
Do replacement rear control arms affect ride comfort?
Yes. Arms with stiffer bushings or solid mounts generally make the rear feel firmer and more direct at the expense of transmitted road noise. OE-style compliant bushings preserve comfort but may not deliver the same handling precision.
What should I bring to the alignment shop after replacing rear control arms?
Bring details about the replaced components and ensure the vehicle is at normal ride height. The alignment shop will need to know whether any adjustable arms were used so they can set toe and camber within the appropriate ranges.
Final Verdict
When choosing rear control arms for a Subaru Legacy, prioritize correct fitment, durable bushings, and corrosion-resistant materials to maintain suspension geometry and prevent recurring alignment problems. Decide between full-arm replacement and bushing service based on the arm's structural condition, available tools, and how long you want the repair to last.Ultimately, select parts that match the Legacy's mounting points and balance ride comfort with durability. After installation, follow up with a professional alignment to ensure predictable handling and even tire wear.
Explore More:
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