Seat Leon 5F III Rear Door Window Guide Seal Sealing Rubber Left N/S 5F4839431J

Seat Leon 5F III Rear Door Window Guide Seal Sealing Rubber Left N/S is a precision component from the Doors and door panels category, responsible for the stable guidance and sealing of the window in the rear left door. Designed as an original part for the Seat brand, it ensures proper window operation geometry and limits the ingress of water and noise into the vehicle interior.

Specifications and technical data

• SKU: 5F4839431J
• Mark: Seat
• Condition: Used
• OEM Part Number: 5F4839431J
• Substitutable numbers: 5F4839431J, 5F4 839 431 J
• Location on the vehicle: Rear, Left
• Category: Doors & Door Skins

Purpose and function in the vehicle

The described guide seal is dedicated for installation in the rear left door of the vehicle, in the side body area. It is responsible for:

• guiding the window in the correct track during raising and lowering,
• limiting lateral play that can cause rattling and vibrations,
• sealing the window edge against the door structure,
• reducing wind noise and air drafts.

Thanks to the proper fit to the door structure, this component supports the correct operation of the window regulator mechanism and acoustic comfort inside the car.

Construction and fitment for the rear left door

The guide seal is profiled for the specific geometry of the rear door on the left side, which allows for installation without additional modifications. The cross-sectional shape and guiding line are adapted to the factory contour of the window frame, ensuring that:

• a stable support for the window edge is provided,
• tightness at the window-to-door interface is maintained,
• the risk of jamming and uneven window operation is minimized.

Such fitment is particularly important in vehicles used daily, where frequent opening and closing of windows requires maintaining the correct guidance geometry.

Benefits of using an original guide seal

Using a component from the same design group as factory Seat parts translates into a number of practical benefits:

• Compatibility with the door structure – maintaining proper pressure against the window and door frame without the need for adjustments.
• Stable operation of the window mechanism – reducing the risk of misalignment, jamming, and excessive load on the regulator.
• Improved driving comfort – better damping of outside noise and a lower risk of water ingress into the door interior.
• Consistency with other body elements – maintaining the factory finish character in the side window area.

Condition of the component and service application

The guide seal is offered as a used part, which allows for an economical repair of the window system while maintaining the original assembly specification. This type of component is particularly useful in situations where:

• the existing guide is worn, brittle, or deformed,
• there are leaks in the area of the rear left window,
• disturbing noises appear during window operation,
• replacement is necessary after door bodywork repairs.

Selecting the correct guide seal for a specific Seat model allows for restoring proper window operating conditions and limiting further wear of the lifting mechanism.

Expanding repairs within the rear door

If you are planning a comprehensive repair or modernization of the door area in your Seat and need other elements from the same group, such as panels, reinforcements, or other components mounted within the door assembly, check the available parts in the Doors and door panels Seat category.

For users interested in a broader context of selecting and operating body elements and equipment components, the guide material regarding the evolution of design solutions in luxury class cars may also be of value – you can find it in the article Evolution of the Mercedes S-Class: from W140 to W222 – innovations, model differences, and Mercedes auto parts over the years, which discusses, among other things, the manufacturers' approach to designing and servicing key components.