Mercedes CLA X118 Front Door Window Rubber Gasket Seal Left N/S A1187250300

Mercedes CLA X118 Front Door Window Rubber Gasket Seal Left N/S is an original body component designed for precise sealing of the driver's side door window. Thanks to its factory-fit for the CLA X118 model, it ensures stable window guidance, reduced cabin noise, and effective protection against water and debris. This is a practical solution for users looking to restore the proper operation of the window mechanism and acoustic comfort inside the vehicle.

Specifications and technical data

• SKU: A1187250300
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1187250300
• Substitutable numbers: A1187250300, A 118 725 03 00
• Location on the vehicle: Front, Left
• Category: Door Seals

Purpose and function of the seal

The presented seal is designed for installation in the front left door of the Mercedes CLA X118 model. The component is responsible for:

• sealing the window perimeter in the door guide,
• limiting air drafts at higher speeds,
• reducing road noise and wind noise in the cabin,
• protecting the interior of the door against moisture and fine debris.

Thanks to its proper profile and flexibility, the rubber conforms to the edge of the glass and the door frame, which helps maintain a stable position of the window during opening and closing.

Construction and fit for Mercedes CLA X118

The seal has been designed specifically for the CLA X118 body, which translates into:

• a shape tailored to the geometry of the front left door,
• compatibility with factory mounts in the door frame,
• correct guidance of the window edge throughout its entire range of motion.

The original Mercedes origin ensures the maintenance of parameters specified by the vehicle manufacturer, including the correct stiffness and elasticity of the material. As a result, the component works well with the window lifting mechanism and other seals within the door area.

Benefits of using an original door seal

Using a factory seal in the front left door allows for the restoration of proper operating conditions in the side area of the body. The most important advantages include:

• better cabin tightness – limiting the ingress of water and moisture into the door interior,
• improved acoustic comfort – reduction of wind noise during highway driving,
• stable window guidance – lower risk of vibrations and improper closing,
• consistent appearance of the door edge with other body elements.

This solution is particularly useful when replacing a damaged, perished, or deformed seal, especially when leaks, rattling, or improper window operation occur.

Professional installation and practical application

The Mercedes CLA X118 Front Door Window Rubber Gasket Seal Left N/S is a component that should be installed in accordance with the manufacturer's service procedures. Proper seating in the door frame and precise pressing in the corner areas affects:

• even pressure of the window along the entire perimeter,
• absence of point leaks in the upper part of the door,
• smooth operation of the window lifting mechanism.

For vehicles operated in variable weather conditions, replacing a worn seal is a simple way to improve daily driving comfort and protect the door interior from the long-term effects of moisture.

If you are planning a comprehensive repair or upgrade of the door area in your Mercedes and need other components from the same group, such as perimeter seals, window frame seals, or additional rubber profiles, check the available parts in the Mercedes door seals category.

For users who are simultaneously servicing thermal comfort systems in the vehicle, a guide on selecting and maintaining air conditioning and heating components may be helpful – detailed tips can be found in the article Air conditioning and heating – parts selection and maintenance for year-round comfort.