Audi A4 B8 Window Lifter Rear Door Left N/S Regulator Mechanism 8K0839461

Audi A4 B8 Window Lifter Rear Door Left N/S Regulator Mechanism is an original component from the Window regulators and motors group, designed for the rear left window in the Audi body. It ensures stable window guidance, proper power transmission, and reliable operation of the entire lifting system, which translates into comfort and safety of vehicle use.

Specifications and technical data

• SKU: 8K0839461
• Mark: Audi
• Condition: Used
• OEM Part Number: 8K0839461
• Substitutable numbers: 8K0839461, 8K0 839 461
• Location on the vehicle: Rear, Left
• Category: Window Motors & Regulators

Purpose and function in the vehicle

The mechanism is designed to operate in the rear left window area, where it is responsible for precise window guidance in the rails and smooth lifting and lowering. Thanks to its fitment for a specific position in the body, the correct operating geometry is maintained, which reduces the risk of jamming, excessive play, or uneven closing.

As an original Audi component, the mechanism works with the factory window motor and the vehicle's electrical system without the need for modifications or adaptations. This solution is particularly beneficial for post-accident repairs, replacing a worn-out system, or restoring full window functionality after a failure.

Construction and technical fitment

The window lifter mechanism uses a system of rails and cables adapted to the construction of the rear left door. The appropriate placement of mounting points allows for installation in the original technological holes, which facilitates service work and reduces repair time.

Key design features:

• dedicated placement in the rear left part of the body,
• compatibility with the factory window control system,
• maintenance of the correct window movement path in the door frame.

Due to the preservation of factory design parameters, it is possible to achieve even pressure of the window against the seals after installation, which helps reduce noise and improves interior sealing.

Benefits of using the original mechanism

Using the original window lifter mechanism in the Audi A4 B8 allows for maintaining the consistency of the entire window system with other door components. Factory fitment minimizes the risk of improper operation, squeaking, or accelerated wear of the rails and seals.

Key practical advantages:

• stable window operation throughout the full range of motion,
• no need to modify the electrical system or mounts,
• easier diagnostics and service in the future thanks to the preservation of OEM solutions.

This solution is especially recommended for professional body and mechanical repairs, where repeatability of the effect and compliance with the manufacturer's service documentation are important.

Component condition and service application

The offered mechanism comes from the used parts segment, which allows for economical repair while maintaining the original design. This type of component is often chosen in situations where there has been mechanical damage to the door, seizure of the rails, or failure of the window lifting system due to wear and tear.

The mechanism will work well both in workshops specializing in the Audi brand and in general service centers that perform body and door equipment repairs. The original design facilitates installation and reduces the risk of compatibility issues typical of some aftermarket replacements.

Audi window regulators and motors – expansion and repairs

If you are planning a comprehensive repair or upgrade of the door and window area in your Audi and need other elements from the same group, such as rails, complete lifter mechanisms, or compatible window motors, check the available parts in the Audi window regulators and motors category.

Expert support when choosing used parts

When selecting components from the secondary market, it is worth using reliable sources of knowledge to consciously compare originals and replacements and properly assess the cost-effectiveness of the repair. An expert guide explaining how to approach the purchase of key drive components may be helpful – you can find it in the article Why it is worth buying used gearboxes and engines – facts instead of myths. Additionally, if you are considering wider use of parts from the secondary market, practical arguments regarding the advantage of OEM components over replacements are presented in the post 5 reasons why a used OEM part is a better choice than a replacement.