Cheap BMW 3 Series Brake Servo

No — the E46 (1998–2006) and E90 (2005–2013) are completely different generations with different bulkheads, master cylinder arrangements, and servo sizes, so the units are not interchangeable. You should only be sourcing a servo from the same generation as your car. Confirm the exact part reference with the breaker against your registration to be sure you get the right unit.

Engine size can influence brake system specification on the BMW 3 Series, as heavier-braking larger-engined variants sometimes carry a different servo size or ratio to cope with greater stopping demands. Within the same generation, a servo from a 318i may not be a straight swap for a 330i even though they look similar. Always quote both your engine size and registration to the breaker so they can match the correct servo to your car.

Trim level alone does not determine brake servo fitment on the BMW 3 Series — the servo spec is driven by the generation and engine size, not whether the car is badged SE, ES, M Sport, or Sport. An M Sport car does carry larger brakes at the caliper and disc end, but whether this also means a different servo should be confirmed with the breaker against your specific registration rather than assumed. You can largely ignore trim badging when searching, but do give the breaker your reg so they can check the full spec.

2005 is right on the boundary between the E46 (1998–2006) and the E90 (2005–2013), as BMW ran both generations in parallel during that overlap period. Your car could be either generation depending on its build date, so you cannot rely on the year alone. Check your V5 or give your registration to the breaker so they can identify the exact generation and source the correct servo.

The E90 received its LCI (Life Cycle Impulse) facelift in 2008, and while much of the running gear carried over, whether the brake servo is identical across the facelift boundary is not something that can be guaranteed without checking. Name the facelift to your breaker and ask them to verify the part number against your registration before agreeing a purchase. This is the safest way to avoid receiving a unit that won't mate correctly with your master cylinder or bulkhead.

Diesel and petrol 3 Series of the same generation can share brake servo specifications where the engine outputs and vehicle weights are similar, but this is not always the case — a heavier or more powerful variant may carry a different servo. Rather than assuming petrol-to-diesel compatibility, quote your exact engine code and registration to the breaker so they can confirm whether the unit they have will suit your car.