Parts for your 2004 Subaru Impreza-Wheel hubs

2004 Subaru Impreza wheel hubs: purpose, care and replacement

Wheel hubs are definitely fitted and relevant on the 2004 Subaru Impreza. Technical sources including the 2004 Subaru Impreza Factory Service Manual, Subaru’s official service information (STIS), and genuine Subaru parts catalog diagrams all show front and rear hub-and-bearing arrangements on the GD/GG-chassis Impreza for MY2004. Non-STI models use a 5x100 hub pattern, with press-in, sealed bearings in the knuckle and a separate hub that carries the wheel studs and ABS tone ring interface.

On a 2004 Impreza, the hub’s job is straightforward but crucial: it provides the mounting face for the wheel, holds the studs, supports the vehicle weight via the bearing, and works with the ABS sensor to deliver clean wheel-speed signals. Because the bearings are sealed, there’s no routine greasing—so the focus is on inspection and correct replacement when wear sets in.

As part of regular servicing, it’s smart to check for play and noise at each corner whenever tyres are rotated or brakes are inspected. A light growl that rises with speed, droning that changes when gently swerving, or warmth at the hub after a drive can all tip you off to a tired bearing. Subaru issued technical bulletins in the early 2000s about rear wheel bearing noise on some models, recommending updated bearings and correct press procedures—so technique matters.

• Common signs of hub/bearing wear: humming or rumbling with road speed, looseness felt at 12-and-6 o’clock wheel shake, ABS warning from a disturbed tone ring/sensor, uneven tyre wear, and metallic swarf on the ABS sensor tip.

When replacement’s due, the 2004 Impreza typically needs the bearing pressed in and the hub pressed onto the inner race. That means a proper press and the correct driver tools. Many workshops simply replace the bearing and hub together to ensure a perfect fit and longevity.

• Good practice:
  • Use OEM-quality bearings and seals, and replace the circlip.
  • Support the correct race when pressing to avoid brinelling.
  • Clean the ABS sensor and confirm air gap, don’t nick the tone ring.
  • Fit a new axle nut, torque to Subaru spec with the vehicle on the ground, then stake it—avoid “rattle-gunning” it tight.
  • After road test, recheck for noise and ABS faults.

Treated right, fresh hubs and bearings will run quietly for years, keeping the Impreza tracking straight, ABS happy, and tyres wearing evenly—just the way it should be for Aussie and Kiwi roads.

Are 2004 Subaru Impreza hubs 5x100 or 5x114.3?

For 2004, Impreza (including WRX and STI) uses 5x100 hubs. That applies to both front and rear on Australian and New Zealand deliveries for that year.

How can someone tell if their 2004 Impreza hub or bearing is failing?

Listen for a speed-dependent hum or growl that changes when gently weaving at highway speeds. Check for wheel play with the car safely lifted, feel for heat after a drive, and scan for ABS faults. Any of these signs usually means it’s time for a hub/bearing job.

Does a wheel hub/bearing replacement need a wheel alignment?

Often it doesn’t, but it’s recommended if the knuckle bolts are loosened or the strut is disturbed. If the steering wheel sits off-centre after the job or you’ve had suspension apart, book an alignment to protect your tyres.