KYB KG4540 Shock Absorber - Front

KYB Gas-a-just Front Shock for Jaguar XJ

The KYB Gas-a-just KG4540 is a monotube suspension shock absorber built as an OE-style replacement for Jaguar XJ, XJ6, XJ12, and XJS front applications. It is designed to restore original ride control while adding firmer damping response for vehicles that work harder, tow, or run larger wheels and tires.

Gas-a-just Line Details

KYB Gas-a-just shocks use a high-pressure monotube design with separate gas and oil chambers. That layout supports fade-resistant operation, quicker response, and more consistent control than many twin-tube designs, making the KG4540 a practical choice for classic Jaguar front suspension service.

Key Features

• Adds up to 25% more damping performance over original equipment shocks
• Monotube construction separates gas and oil for consistent response
• High-pressure nitrogen gas helps improve steering response
• Triple chrome plated piston rod helps reduce seal wear
• Dust cover included
• Lower mount type: E2 (11.1 x 32)
• Upper mount type: S1
• Compressed length: 11.42 in; extended length: 18.31 in; stroke length: 6.89 in

Detailed Description

KYB KG4540 is engineered for front suspension use on Jaguar XJ and related models where precise damping and stable road feel matter. The Gas-a-just design uses an air-free hydraulic working chamber for control and a separate high-pressure nitrogen chamber for immediate reaction when suspension demands increase. This helps maintain consistent performance during normal driving and under heavier load conditions. This part cross-references Monroe Shocks & Struts (e.g., 39004) for the same application.

What It Helps Address

• Excessive front-end bounce after bumps
• Loose or delayed steering response
• Nose dive during braking
• Reduced control from worn OE-style shocks
• Fade in suspension performance during repeated road inputs

Installation Notes

• Fits 1968-1971 Jaguar XJ, front
• Fits 1972-1986 Jaguar XJ6, front
• Fits 1973-1979 Jaguar XJ12, front
• Fits 1981-1986 Jaguar XJ12, front
• Fits 1976-1995 Jaguar XJS, front
• Replace the suspension strut and coil spring assembly according to the manufacturer’s instructions.
• Verify mount style and dimensions before installation on Jaguar XJ front suspension service.

Quality Assurance

KYB designs the Gas-a-just line as an OE monotube replacement for vehicles that need restored control and consistent damping. The KG4540 is built for direct front suspension service on confirmed Jaguar applications, including Jaguar XJ, XJ6, XJ12, and XJS models.