Parts for your 2004 Subaru Impreza-Control arms

2004 Subaru Impreza control arms — what they do and how to look after them

Control arms are absolutely used on the 2004 Subaru Impreza. Technical references including the Subaru Factory Service Manual for the 2004 Impreza/WRX (Chassis and Suspension sections, STIS), the Haynes Workshop Manual for Subaru Impreza 2001–2007, and OEM/aftermarket parts catalogues all specify a MacPherson strut front suspension with a lower control arm (also called a transverse link). The rear uses struts with multiple lateral links and a trailing arm, which function as control arms for wheel location. So yes, control arms are relevant to this model, front and rear.

On a 2004 Impreza, the front lower control arms tie the hub/knuckle to the body, letting the wheel move up and down while holding camber and caster steady. They pivot on rubber bushes at the chassis and connect to the steering knuckle via a ball joint. Depending on trim, the front arms may be pressed steel (many non-turbo models) or alloy (common on WRX/STI variants). At the rear, the lateral links and trailing arm set the wheel’s fore–aft and side-to-side location, keeping the tyre contact patch stable through bumps and cornering.

Good control arms and bushes mean crisp steering, stable braking, and even tyre wear. Worn bushes or a sloppy ball joint can cause vague steering, clunks on bumps, shimmy under braking, and feathered or inner-edge tyre wear.

• Tell-tale signs: knocking over speed humps, steering wandering on the motorway, uneven tyre wear, or a “floaty” feel in mid-corner bumps.
• Inspection tips: check rubber bushes for cracks, separation, or oil soak, test the ball joint for play, look for bent arms from kerb strikes, and check rear lateral links for perished bushes.

During regular servicing, a quick visual and pry-bar check of the front arms, rear links, and all bushes is smart—especially on cars doing lots of city kerb hops or gravel kilometres. If any joint has play or a bush is torn, it’s time to replace. Many owners choose complete arm assemblies for convenience (new bushes pre-fitted), while performance-minded drivers may press in upgraded bushes. Always torque fasteners at normal ride height and book a wheel alignment afterwards. Replacing components in axle pairs helps keep handling balanced side to side.

Note: Variants with alloy front arms use different bush styles and geometry, so parts aren’t always interchangeable. Refer to the factory information or a trusted parts specialist to match the VIN before ordering.

Popular questions

Do all 2004 Subaru Imprezas have front control arms?

Yes. Per the Subaru service manual and common parts listings, every 2004 Impreza uses a front lower control arm in its MacPherson strut setup. Rear suspension uses lateral links and a trailing arm that act as control arms for wheel control.

Should the whole control arm be replaced, or just the bushes/ball joint?

It depends on condition and budget. If the arm is straight and only the bushes are worn, pressing in new bushes and fitting a fresh ball joint works well. If the arm is bent, corroded, or you want a quicker job, a complete arm assembly with bushes pre-installed is the go. Alignment is required either way.

What happens if worn control arm bushes are ignored?

Expect vague steering, clunks, and accelerated tyre wear. In bad cases, braking stability suffers and the car can tramline over rutted roads. Fixing worn bushes or a loose ball joint restores proper geometry and keeps tyres wearing evenly.