What is a control arm on a Subaru?
The control arm is a suspension link that connects the wheel hub to the car's frame, guiding wheel motion and helping keep proper alignment. In Subaru models, you’ll typically encounter a lower control arm in the front suspension and a similar or multi-link setup in the rear, depending on the model and generation.
What it does and how it fits into the suspension
Subaru uses independent suspension systems to improve ride quality and handling. The control arm shapes the wheel's path through the suspension's travel, transmits forces from the wheel to the chassis, and works with bushings and ball joints to absorb bumps while preserving alignment geometry.
Front vs rear control arms
Front control arms (usually lower arms in Subaru's MacPherson-strut layout) connect the steering knuckle to the subframe. They control camber and toe changes as the suspension moves. Rear control arms (which may be part of a multi-link or double-wishbone setup on many Subarus) provide similar control over wheel position and contribute to ride stability.
Key components and how it works
Understanding the parts helps explain why control arms matter for ride quality and steering feel.
- Control arms (lower and/or upper) that pivot on bushings at the chassis
- Ball joints connecting the arm to the wheel hub
- Bushings that cushion the arm's mounting and absorb vibration
- Mounting brackets and bolts securing the arm to the subframe
- Optional reinforcement brackets or links in some Subaru models
In practice, the control arm works with the strut or spring to maintain the wheel’s correct angle relative to the body, while allowing vertical motion to absorb bumps. Worn bushings or a damaged ball joint can introduce play, noise, or misalignment.
Signs of wear and when to inspect or replace
Noticeable symptoms can indicate a worn control arm or its bushings. If you observe any of the following, have the suspension inspected by a qualified technician.
- Clunking, banging, or creaking noises when hitting bumps or during braking
- Uneven tire wear or sudden changes in toe alignment without wheel alignment
- Steering pull, wandering, or imprecise steering feel
- Visible damage to the arm, rubber bushings, or ball joint boot
- Noticeable looseness or excess play in the wheel when jacked up and moved
Addressing worn control arms is important for maintaining handling, steering response, and tire longevity. If a failure is suspected, a professional inspection is recommended before driving long distances.
Replacement considerations for Subaru models
Replacing a control arm involves choosing between OEM (original equipment manufacturer) parts or aftermarket equivalents, and typically includes new bushings or ball joints as needed. Most shops replace control arms in pairs (both sides of the axle) to preserve balanced handling, and alignment is required afterward to restore proper toe and camber settings.
- Cost range: Expect roughly $300–$900 per arm for parts plus $150–$400 for labor per arm, depending on model, location, and whether additional components are replaced
- Labor and parts vary by model: front arms are common, rear arms depend on the suspension design (multi-link rear is common on many Subarus)
- After replacement, an alignment is typically necessary to ensure proper geometry
When replacing, technicians may also inspect related components such as the bushings, ball joints, tie rods, and subframe for wear, since these parts can be affected by a failing control arm or failure can accelerate wear elsewhere.
Subaru-specific notes
Subaru's suspension architecture varies by model year. Many modern Subarus use a MacPherson strut front suspension with a lower control arm, while the rear uses a multi-link arrangement on most models. Some variants (early-generation cars or certain trims) may use different configurations. It’s important to refer to the service manual for exact part numbers and torque specs for your model year. Regular inspection during routine maintenance can catch worn bushings or ball joints before they lead to steering concerns or tire wear.
Summary
The control arm is a key suspension link that connects the wheel hub to the vehicle frame, guiding wheel movement and preserving alignment. In Subarus, designs vary by model, but the principle remains the same: a sturdy arm with bushings and a ball joint that can wear over time, potentially causing clunking noises, misalignment, and uneven tire wear. Replacement is common in modern vehicles and is usually followed by an alignment to restore correct geometry and handling.
