Audi A4 S4 RS4 B8 Rear Door Catch Seal Rubber Gasket Left N/S 8K0839923B

Audi A4 S4 RS4 B8 Rear Door Catch Seal Rubber Gasket Left N/S is a precisely fitted component from the Door seals group, designed for the rear left body area. It is responsible for the tight seating of the door catch, noise reduction, and protection against moisture and contaminants, which translates into stable operation of the locking mechanism. This is a solution for users who want to maintain factory acoustic comfort and proper door operation in their Audi.

Specifications and technical data

• SKU: 8K0839923B
• Mark: Audi
• Condition: Used
• OEM Part Number: 8K0839923B
• Substitutable numbers: 8K0839923B, 8K0 839 923 B
• Location on the vehicle: Rear, Left
• Category: Door Seals

Purpose and function of the seal

The presented seal has been designed specifically for the rear left part of the body, in the area of the door catch. Its tasks include:

• limiting the penetration of water and dirt into the lock and catch area,
• stabilizing the operation of the locking mechanism,
• reducing unwanted sounds when closing the door,
• maintaining proper tightness of the door circuit in the rear part of the vehicle. Thanks to the correct rubber profile, the seal works with the door and body structure, ensuring predictable door behavior during daily use.

Construction and material properties

The seal is made of flexible rubber material selected for operation in typical passenger car operating conditions. The material structure has been designed to:

• maintain elasticity during repeated opening and closing of the door,
• provide resistance to temperature changes and typical mechanical loads,
• limit the transmission of vibrations from the body to the catch mechanism. Such properties help maintain even pressure of the door against the body, which supports cabin acoustic comfort and improves the subjective feeling of closing quality.

Benefits of using an original Audi seal

Using a component sourced from Audi allows for maintaining compliance with the factory geometry of the door and body. Key advantages include:

• Precise fit to the rear left door area – no need for modifications or shape adjustments.
• Consistency with other door system components, such as the lock, catch, and other seals.
• The ability to restore the original level of tightness after replacing a worn component. For users who want to better understand the importance of original components and the selection of used parts by identification numbers, the article on the legendary five-cylinder Audi engine and the selection of original Audi parts, which discusses the practical aspects of using OEM parts, may be helpful.

Vehicle placement and assembly aspects

The seal works in the rear left part of the body, in the immediate vicinity of the door catch. Proper seating in this area is important for:

• maintaining the correct position of the door relative to the body,
• limiting play in the locking mechanism,
• protecting the lock area from excessive dirt. During assembly, it is worth paying attention to the even placement of the seal in the guides and sockets provided by the manufacturer, so as to maintain the continuity of the sealing line and avoid local material stress.

Application in service and door area modernization

Replacing the rear left catch seal is a typical element of service work during door regeneration, especially when leaks, increased noise, or closing problems occur. In combination with other elements from the Door seals group, you can effectively refresh the side body area, improving the comfort of using the vehicle. If you are planning a comprehensive repair or modernization of the door area in your Audi and need other elements from the same group, such as perimeter door seals, threshold seals, or window frame sealing elements, check the available parts in the Audi door seals category.