2005-2008 Subaru Legacy GT Front vs Rear Brakes: What Wears First and What to Replace

By Core Brake Parts Tech Team — Circleville, OH warehouse

On a 2005-2008 Subaru Legacy GT, the front brakes almost always wear out first. The fronts carry most of the stopping load, so front pads typically need replacing before the rears, while the rear pads and rotors usually last longer but should never be ignored. The smart move is to inspect all four corners at every pad job and replace parts by axle, never one wheel at a time.

How the Legacy GT Brake System Is Laid Out

The turbocharged Legacy GT uses disc brakes at all four wheels. Up front it runs a large vented rotor: DBA lists its 2005-2008 Legacy GT front rotor at 316 mm in diameter and 30 mm thick, with a 58 mm center bore and five lug holes. The same rotor is listed for several later Subarus, including some Tribeca, Outback, Forester and WRX model years, which helps parts availability.

The rear axle also uses discs, not drums. Rear rotors and pads are smaller than the fronts because the rear brakes do less of the work. Rear rotors for the 2005-2008 Legacy GT are sold under their own part numbers, so always order front and rear parts separately and confirm the axle position on the listing.

The hydraulic system is a dual-circuit, diagonally split design. In Subaru's own recall notice, the company explains that each circuit works independently and diagonally across the vehicle, so if one circuit fails the other half still works. That matters for diagnosis: a leak on one side can change how the pedal feels at both ends of the car.

What Wears First: Front vs Rear

A turbo sedan or wagon that gets driven with some enthusiasm heats the front rotors hard, which is why front pads go first and why front rotors are more likely to develop pedal pulsation. The rear brakes see less heat, but on a Legacy that lives in a snowy state they can fail from the outside in: rust eats the rotor faces and the pad abutment hardware, and the caliper slides can stick. It is common to find rear pads worn unevenly, with one pad much thinner than the other, because of sticky slides rather than mileage.

Symptoms and How to Tell Which End Needs Work

• Scraping or squealing when you brake: Subaru's owner manual says the disc brake pad wear warning indicators make a warning noise when the pads are worn. Listen with the window down at low speed; noise from the front usually means front pads.
• Steering wheel shake under braking: points to the front rotors, which take the most heat on this car.
• Pulsation felt in the seat or pedal but not the wheel: often the rear rotors.
• Grinding from the rear after the car sits: light surface rust on rear rotors is normal and should clean off in a few stops. If it does not, pull the rear wheels and check pad thickness and rotor faces.
• Soft or long pedal: not a pad problem. Check for fluid leaks at the lines, hoses and calipers before replacing anything else.

The only reliable check is to look. With the wheels off, measure the friction material on both the inner and outer pads at each corner, and look at the rotor faces for scoring, a raised lip at the outer edge, or heavy rust. Compare the rotor thickness to the minimum thickness stamped on the rotor itself.

The Brake Line Recall You Should Check First

Before any rear brake work on a 2005-2008 Legacy GT, check the recall status. NHTSA recall 14V-311 (Subaru campaign WQK-47) covers certain 2005-2009 Legacy and Outback models that are or ever were registered in salt-belt states, including Ohio, Pennsylvania, New York, Michigan, Illinois and others. Subaru determined that salt water could splash on the brake lines through a gap in the fuel tank protector and corrode them, and a perforated line can leak fluid and cause the related circuit to lose effectiveness. Subaru's remedy is to inspect the lines, apply anti-corrosion material, and replace any lines found unacceptable, at no cost to the owner.

If you are doing rear brakes on one of these cars, look at the lines running back toward the rear axle while you are under it. If they are flaking or wet, stop and get the recall done, or replace the damaged sections with replacement brake lines, before putting new pads on.

What to Replace, and What to Replace at the Same Time

Front pad job: the Legacy GT front pad uses the D1078 shape, which Hawk sells as the HB533 family in several compounds. For a spirited street-driven GT, our Hawk HP Plus front brake pad set for the 2005-2008 Legacy GT is a performance street option; if you want a quieter daily-driver pad, browse ceramic brake pads. Replace the front rotors if they are below minimum thickness, warped, or deeply scored. New pads on worn rotors bed in poorly and often bring the vibration right back.

Rear pad job: rear pads use a different part number from the fronts. Because rear rotors on salt-state cars usually die from rust rather than wear, plan on new brake rotors for the rear if the faces are pitted or the edges carry a heavy lip.

Always replace in axle pairs. Both front sides together, both rear sides together. Mixing new and old parts on the same axle causes pull.

Also worth replacing at the same time:

• Abutment clips and slide pin boots from a brake hardware kit. Rusty clips are a leading cause of the uneven rear pad wear seen on these cars.
• Brake fluid, if it has not been flushed in a few years. Use the fluid type printed on the master cylinder reservoir cap.
• Brake calipers only if a piston is seized or leaking, or a slide will not free up after cleaning and fresh grease.

How Hard Is the Job?

Front pads and rotors on the Legacy GT are a reasonable driveway job for someone with a jack, stands, a torque wrench and basic hand tools. The rear is similar, though rusty rotors can be stubborn to free from the hub. Torque the caliper bracket bolts and lug nuts to the values in the factory service manual rather than guessing. After any pad or rotor change, pump the pedal until it is firm before moving the car, then bed in the new pads following the pad maker's procedure.

If the job turns into line or caliper replacement, the brakes must be bled afterward, and a car with ABS needs careful bleeding to avoid a soft pedal. That is the point where many owners hand it to a shop.

Frequently Asked Questions

Do front and rear brakes wear at the same rate on a Legacy GT?

No. The fronts do most of the braking and usually wear out first. The rears last longer in normal driving, but on cars in salt states rust can force rear rotor and hardware replacement before the pads are worn down.

Does the 2005-2008 Legacy GT have rear drum brakes?

No. The Legacy GT has disc brakes at all four wheels. The rear rotors are smaller than the fronts and use their own part numbers.

Will Legacy GT front rotors fit other Subarus?

DBA lists its 316 mm Legacy GT front rotor as also fitting certain Tribeca, Outback, Forester and WRX model years. Always confirm fitment for your exact year and trim before ordering.

Should I replace rotors every time I replace pads?

Not always. Replace them if they are below the minimum thickness stamped on the rotor, cause vibration, or are deeply scored or rusted. Smooth rotors within spec can be reused.

Is my Legacy GT covered by the brake line recall?

Recall 14V-311 covers certain 2005-2009 Legacy and Outback models registered in the listed salt-belt states. Check your VIN on NHTSA's recall lookup or with a Subaru dealer.

Sources

1. DBA 4000 Series front rotor, 2005-2008 Legacy GT - front rotor diameter, thickness, center bore, vented design and cross-fitment
2. DBA Street Series rear rotor, Legacy 2005-2008 - rear disc rotor sold as a separate rear-position part
3. Hawk HB533 application list - D1078 front pad shape and compound options for the Legacy GT
4. NHTSA recall 14V-311 owner notice (Subaru) - brake line corrosion, affected states, diagonal dual-circuit design, remedy
5. Subaru Legacy owner manual - pad wear indicators - audible warning when pads are worn
6. Subaru Legacy owner manual - pad replacement - driving on the wear indicator leads to rotor damage