Ford Fiesta Mk8 Coil Spring Rear Left Right N/O/S K1BY-5B859-AAC K1BY-5560-AAC

Ford Fiesta Mk8 Coil Spring Rear Left Right is an original rear suspension spring designed for installation on either the left or right side of the axle in the Ford Fiesta Mk8 model. This component ensures proper body support, vehicle stabilization, and predictable handling, serving as a vital part of the suspension system. Thanks to the factory specification, the Ford Fiesta Mk8 rear spring allows for maintaining suspension performance characteristics consistent with the manufacturer's design.

Specifications and technical data

• SKU: K1BY-5B859-AAC
• Mark: Ford
• Condition: Used
• OEM Part Number: K1BY-5B859-AAC
• Substitutable numbers: K1BY-5B859-AAC, K1BY5B859AAC, 2289478
• Location on the vehicle: Rear, Right, Left
• Category: Other Steering & Suspension Parts

Purpose and function in the Ford Fiesta Mk8 suspension

The presented coil spring operates in the rear suspension of the Ford Fiesta Mk8, where it is responsible for maintaining the correct body height and absorbing loads acting on the rear axle. It can be installed on both the left and right sides, which facilitates part selection during repairs or when replacing a pair of components on the axle.

By maintaining factory geometry and deflection characteristics, the spring helps to maintain proper alignment, cornering stability, and predictable car reactions during braking and acceleration. This is particularly important in daily use, where repeatable, safe vehicle behavior is essential.

Benefits of using an original Ford rear spring

Using an original suspension component in the Ford Fiesta Mk8 translates into a number of practical advantages:

• maintaining the factory performance characteristics of the rear suspension,
• proper body support under various loads,
• consistent operation with stock shock absorbers and other suspension system elements,
• reduced risk of uneven tire wear resulting from incorrect suspension height,
• easier diagnostics and service due to compliance with manufacturer documentation.

A used original component is a reasonable compromise between repair costs and maintaining the correct suspension performance parameters. In many cases, this is a more predictable solution than uncertain aftermarket replacements with unknown characteristics.

Vehicle placement and installation aspects

The spring is designed for installation on the rear axle of the Ford Fiesta Mk8, with the possibility of use on both sides of the vehicle. This solution simplifies the service process – the same type of element can be used on both the left and right sides, which facilitates the paired replacement recommended when working on the suspension.

During installation, it is worth paying attention to:

• the use of appropriate spring compressor tools,
• checking the condition of seats, washers, and mating components,
• verifying suspension geometry after completing the work.

Such an installation allows you to fully utilize the potential of the original Ford rear spring and reduce the risk of additional interventions in the suspension system in the future.

Part selection by numbers and integration with other elements

The spring belongs to a group of suspension elements for which precise selection for a specific model version is crucial. In practice, this means the necessity of verifying compatibility by part numbers and interchangeable numbers, which allows avoiding the installation of a component with different deflection characteristics than those intended for a given vehicle.

This element works in conjunction with shock absorbers, control arms, the rear beam, and the braking system, influencing ride comfort, stability, and the effectiveness of force transmission to the road surface. A properly selected rear spring is particularly important during intensive city use and when frequently carrying passengers or luggage.

If you are planning a comprehensive repair or upgrade of the rear suspension area in your Ford and need other elements from the same group, such as springs, shock absorbers, or mounts, check the available parts in the Other Ford category.

Technical support and knowledge about suspension systems

When selecting suspension elements and analyzing the differences between equipment versions and sport vs. standard specifications, knowledge of the construction of suspension and drivetrain systems in compact and sports cars can be helpful. A broader context of the operation of suspension, brakes, and drivetrain in high-performance cars can be found in the article Audi RS vs other models – what is hidden under the hood and chassis?, which discusses, among other things, the impact of chassis design on vehicle handling.