Steering rack

EPS and hydraulic steering racks are both prone to a range of mechanical/electrical issues. They can also be damaged from collisions and under-car impact. We sell them frequently for both scenarios.

Hydraulic steering rack issues

Hydraulic racks—which were disused after the E-Generation—were particularly unreliable and prone to fluid leaks.

EPS steering rack issues

The newer EPS steering racks are much less problematic—but are still prone to issues nonetheless. They have two common faults: 1) electrical motor failure, and 2) acoustic knocking.

• Electrical motor failure: The motors in BMWs EPS racks do fail. When this happens you can either replace the entire rack or just the motor—in either case you will need to factor in coding. Coding a second-hand motor/rack will require decent aftermarket coding/scan tools (Autologic or comparable.) It is also worth lining up option codes such as Active Steering and Park Assist to minimise the amount of coding required.
• Knocking: An acoustic knocking issue will occur in most F-Generation vehicles (including 1, 2, 3 and 4 Series, X3 and X4.) It can occur as early on as 50,000 kms and is due to a design fault in the racks thrust piece. This thrust piece can be replaced using a genuine BMW repair kit that is designed to address the problem—however it’s difficult to get the adjustment right without a specialised precision tool that electronically measures the adjustment. You can try adjust it by hand, but it’s very hard to get it right—too loose and the steering is too loose—to tight, vice versa. Some BMW dealership and workshops within Australia might be able to perform the procedure, but we’re not aware of any. In most cases people put up with the noise, as it doesn’t affect the actual handling of the car.

There are two different types of steering racks in late-model BMWs: hydraulic racks and and EPS (electric power steering) racks. Both play the same role in converting the rotational movement of the steering wheel into the lateral motion needed to change the direction of the vehicle’s wheels.

How a hydraulic steering rack works

Hydraulic power steering systems utilise a hydraulic pump to provide assistance in steering. The steering rack integrates with this system, using hydraulic pressure to ease the effort required to turn the wheels. This setup offers a smooth and fluid steering feel, making it easier to handle the vehicle, especially at lower speeds.

How an EPS rack works

Electric Power Steering (EPS) systems replace the hydraulic pump with an electric motor attached directly to the steering rack. This design significantly reduces energy consumption, as the motor only operates when steering assistance is needed, improving overall fuel efficiency. EPS offers enhanced adaptability, with the ability to easily adjust steering assistance levels and feedback to suit different driving conditions or preferences. The precision and programmability of EPS systems also support advanced driver assistance features.

Hydraulic racks can easily be matched using the BMW part numbers from the catalogue.

EPS racks are more difficult to match. The hardware can be matched by matching the BMW part number, but second-hand EPS racks have coding issues relating to the motors. These motors can be recoded using decent coding/scan tools (Autologic or comparable) but without this you will need to match up option codes such as Active Steering and Park Assist.

If only the mechanical section of your EPS rack is damaged, you can swap the motor to avoid coding issues—meaning you only need to match the genuine BMW part number.

To find a compatible steering rack you can provide our team with your vehicle’s 17-digit VIN—we’ll check our stock for a match.

Hydraulic racks have very little/no interchangeability between models. This is because the physical dimensions, mounting points, and hydraulic connections can vary significantly between different models.

EPS racks do have some interchangeability between models. Specifically there is a lot of interchangeability between the F Generation 1 Series, 2 Series, 3 Series and 4 Series that share the same engine. For instance, the rack in the F30 320d is the same as in the F32 420d—but the rack in the F20 120i is not the same as F20 135i.