Brake Caliper Mercedes W209 Rear Left Wheel N/S Braking Unit 42/20

Brake Caliper Mercedes W209 Rear Left Wheel N/S Braking Unit is a factory-original braking system component designed for installation on the rear axle on the driver's side. This used, original caliper ensures proper brake pad guidance and stable piston operation, which translates into consistent and predictable braking during daily use. It is a solution for drivers who are looking for a technically matched component rather than universal replacements.

Specifications and technical data

• SKU: A0044233198
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A0044233198
• Substitutable numbers: A0044233198, A 004 423 31 98
• Location on the vehicle: Rear, Left
• Category: Calipers & Brackets

Purpose and fitment for the braking system

The presented caliper is a component in the Brake Calipers and Brackets category, designed specifically for the rear left axle in Mercedes W209 series models. The vehicle placement has been factory-defined, ensuring the correct working geometry of the pads relative to the disc and proper guidance of braking forces.

The original Mercedes origin means compliance with the vehicle's factory design specifications – from the mounting hole spacing and piston diameter to compatibility with the stock master cylinder and brake lines. Choosing this component reduces the risk of installation issues and improper system operation.

Construction and technical characteristics of the caliper

The Brake Caliper Mercedes W209 Rear Left Wheel N/S Braking Unit operates in a hydraulic system where brake fluid pressure forces the piston to move and press the pads against the disc. The design intended for this specific vehicle model ensures:

• stable pad guidance in the carrier,
• correctly matched clamping force for the disc diameter,
• compatibility with the stock ABS/ESP system,
• compatibility with factory lines and mounts.

As a result, the caliper maintains operating parameters close to the factory-installed component, which is particularly important for maintaining even braking on both wheels of the rear axle.

Benefits of using an original used caliper

Choosing a used Brake Caliper Mercedes W209 Rear Left Wheel N/S Braking Unit is a solution that allows you to balance cost control with maintaining the factory concept of the braking system. Compared to random replacements, the original component:

• maintains compliance with the vehicle manufacturer's design,
• reduces the risk of fitment issues and leaks,
• facilitates service – the mechanic is familiar with the design and standard maintenance procedures,
• allows for consistent braking parameters on both sides of the axle.

For many users, this is a reasonable compromise between repair costs and maintaining the car's driving characteristics. The original brake caliper is especially recommended where predictable vehicle behavior during emergency braking is a priority.

Mounting position: rear – left side of the vehicle

The vehicle placement defined as rear – left side means that the caliper is intended for installation on the driver's side of the rear axle. Correct side assignment is crucial due to:

• the direction of the bleeder valve and proper system bleeding,
• brake line routing and protection against abrasion,
• maintaining the correct operating direction of auxiliary mechanisms (e.g., handbrake lever, if applicable to the specific variant).

Selecting the caliper exactly for this mounting position minimizes the risk of installation errors and operational problems after the repair.

Safe selection of used braking system components

When choosing a used brake caliper, it is worth paying attention to part number compatibility, the condition of working surfaces, and the completeness of the element. A detailed list of aspects to check when purchasing used brake components can be found in the article: Second-hand braking system: how to safely select discs, calipers, and ABS?. This is a practical addition to your knowledge when planning repairs or upgrades to the braking system.

If you are planning a comprehensive repair or upgrade of the braking zone in your Mercedes and need other elements from the same group, such as additional calipers, carriers, or mounts, check the available parts in the Mercedes Brake Calipers and Brackets category.