Mercedes W177 W118 W243 Seatbelt Buckle Clip Lock Rear Left A1778603502

Mercedes W177 W118 W243 Rear Left Seat Belt Buckle is an original safety system component, designed for installation on the rear left side of Mercedes vehicles of the appropriate body series. The precise design of the buckle ensures proper cooperation with the rear seat belt, which translates into safe and stable passenger restraint.

Specifications and technical data

• SKU: A1778603502
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1778603502
• Substitutable numbers: A1778603502, A 177 860 35 02, A1778602100, A 177 860 21 00
• Location on the vehicle: Rear, Left
• Category: Seat Belts & Parts

Vehicle Application and Placement

The presented rear left seat belt buckle has been specifically designed for installation on the rear seat on the driver's side. It is responsible for securely fastening the seat belt, correctly guiding the webbing, and maintaining the proper position of the buckle relative to the seat.

Its dedicated placement on the vehicle minimizes the risk of incorrect installation and preserves the factory geometry of the passive safety system. This ensures that the seat belt system functions according to the vehicle manufacturer's specifications.

Seat Belt Buckle Construction and Function

The buckle is a component of the system that transfers loads from the seat belt to the vehicle's body structure. It is responsible for:

• Stable belt fastening – secure engagement of the belt tongue into the buckle receptacle,
• Controlled lock release – precise operation of the release button,
• Maintaining the correct belt position relative to the seat and passenger.

The original buckle design ensures compatibility with the factory seat belt and other system components, which is crucial for maintaining an adequate level of protection.

Benefits of Using an Original Mercedes Buckle

Using a factory buckle in the seat belt system offers a range of practical benefits:

• Full compatibility with the safety system – a component designed to work with the specific seat and body structure.
• Proper operation of the locking mechanism – predictable performance during daily use.
• Accurate dimensional fit – no play, correct belt routing, and stable attachment to the vehicle's structure.
• Consistency with factory standards – maintaining the original configuration of the vehicle's safety system.

Used Product Characteristics

The seat belt buckle is a used part, sourced from a dismantled vehicle, which allows for combining original manufacturing quality with a more favorable purchase price. This type of solution is particularly attractive for collision repairs or for restoring a vehicle to its factory specifications without resorting to unknown aftermarket replacements.

For many Mercedes car owners, choosing original, used safety system components is a sensible compromise between quality and economy, provided the parts are correctly selected for the specific body version and interior configuration.

Vehicle Fitment and Additional Technical Information

Before purchasing, it is recommended to compare the buckle's design with the currently installed part in your vehicle and verify its compatibility with the service documentation. The product has an assigned OEM part number and related interchangeable numbers, which facilitates unambiguous identification and selection for a specific car model.

If you also need other parts from the Mercedes Seat Belts and Parts category, check out the Mercedes Seat Belts and Parts available in our store to complete your safety system component set.

Safety and Operation in AWD Vehicles

In Mercedes vehicles equipped with advanced all-wheel-drive systems, a properly functioning seat belt system is particularly important for maintaining vehicle control in challenging road conditions. To better understand the specific construction of such cars and related components, it is worth reading the article xDrive, 4Matic, quattro or 4Motion – Comparison of AWD Systems from BMW, Mercedes, Audi and VW, which discusses, among other things, service characteristics and the selection of used components.