Parts for your 2006 Subaru Impreza-Brake wheel cylinders

2006 Subaru Impreza brake-wheel-cylinders: fitted on drum-brake models, not on rear-disc models

Technical references confirm the 2006 Subaru Impreza may use brake-wheel-cylinders depending on the rear brake type. The Subaru Factory Service Manual (2006MY Impreza, Brake section – Drum Brake) and Subaru FAST electronic parts catalogue list rear drum assemblies with wheel cylinders for certain non-turbo grades, while models with rear disc brakes (e.g., many 2.0R and WRX variants) don’t use wheel cylinders. Australian and New Zealand aftermarket catalogues (e.g., Bendix) also list rear wheel cylinder part numbers for GD/GG Impreza 2000–2007 drum-brake variants. So, if a 2006 Impreza has rear drum brakes, brake-wheel-cylinders are relevant, if it has rear discs, they’re not used.

On drum-brake 2006 Imprezas, the brake-wheel-cylinder’s job is simple but critical: it converts hydraulic pressure from the master cylinder into outward force on the brake shoes, pressing them against the drum to slow the car. Each rear drum has a wheel cylinder with two small pistons under rubber dust boots. Over time, moisture and old brake fluid can corrode the bore, seals can harden, and the pistons can seize or leak.

Tell-tale signs it’s time to replace include:

• Fluid weeping under the dust boots or inside the drum
• Spongy pedal, longer stopping distances, or the car pulling to one side
• Uneven shoe wear or contaminated linings

There’s no fixed replacement interval, but it’s smart to inspect the wheel cylinders whenever the rear shoes are checked or replaced, and whenever brake fluid is flushed (typically every two years with the correct DOT fluid specified by Subaru). If one side is leaking or seized, replace wheel cylinders in pairs and fit new shoes if they’ve been soaked in fluid. Always clean the backing plate, check the shoe adjuster moves freely, and bleed the system properly afterwards. A careful road test and recheck for leaks finishes the job.

DIYers should use quality parts, new copper washers where applicable, and avoid getting any grease or brake fluid on the friction surfaces. If the car has rear disc brakes, skip the wheel-cylinder chat—those cars use caliper pistons instead, and the service focus shifts to caliper slides, seals, pads and rotors.

FAQs

How can I tell if my 2006 Impreza has wheel cylinders?
Pop a rear wheel off and look: a drum brake (closed cylindrical drum over the shoes) uses a wheel cylinder, a disc brake has a visible rotor and caliper. Many AU/NZ base non-turbo trims ran rear drums, while 2.0R and WRX typically have rear discs. Your build plate, VIN-based parts lookup, or the Subaru workshop manual will also point to the correct setup.

Do wheel cylinders need regular replacement on a 2006 Impreza?
There’s no set mileage, but they should be inspected at each brake service. Replace if there’s any sign of leakage, corrosion, sticking pistons, or if the dust boots are torn. Always do both sides, bleed the system, and consider new shoes if fluid has contaminated the linings. Keeping brake fluid fresh every two years helps wheel cylinders last longer.

Can I rebuild the wheel cylinders or should I replace them?
Rebuild kits exist, but new wheel cylinders are usually inexpensive and save time. In Aussie and Kiwi conditions where moisture and road grime are common, outright replacement of both rear cylinders often makes the most sense for reliability. If rebuilding, the bore must be spotless and within spec per the service manual.