Mercedes-Benz W212 W204 E-Class C-Class Brake Master Pump A2124300301 - Used Original Parts

Diagnosis and Common Symptoms

A failing brake master cylinder on the W204 and W212 chassis typically manifests as a "spongy" or sinking brake pedal, where the pedal slowly travels to the floor while maintaining steady pressure at a stoplight. This is often caused by internal seal degradation, allowing high-pressure fluid to bypass the primary or secondary pistons. Technicians may encounter fault codes related to "Brake Pressure Sensor Plausibility" or "Pressure Sensor Signal Improbable" within the ABS/ESP module. Physical symptoms include external fluid leakage at the mounting interface between the master cylinder and the vacuum booster, which, if left unaddressed, will deteriorate the booster's internal diaphragm.

Introduction

At M.S. Motor, we prioritize hydraulic integrity by offering only Genuine Mercedes-Benz brake master pumps salvaged from low-mileage donor vehicles. Each unit undergoes a rigorous pressure-bench test to ensure that internal bypass valves and seals hold under maximum load. Choosing a Genuine used component ensures perfect bore alignment and material compatibility that aftermarket alternatives often fail to replicate.

Product Details

• Brand: Mercedes-Benz
• Model Compatibility: C-Class (W204), E-Class (W212), GLK-Class (X204)
• Part Name: Brake Master Pump / Master Cylinder
• Part Number: A2124300301
• Condition: Genuine Used (Tested Working)
• Notes: Requires professional hydraulic bleeding. Ensure the brake booster is free of residual fluid before installation to prevent future vacuum failure.