KYB 551131 Suspension Strut - Front Left

KYB Gas-a-just Front Left Strut for Lexus IS

The KYB Gas-a-just 551131 is a monotube suspension strut built as an OE-style replacement for the front left position on select Lexus IS models. It is engineered to restore original handling response, steering control, and ride consistency for daily driving and heavier-duty use.

Compatible with 2006-2016 Lexus IS350, 2006-2015 Lexus IS250, and 2016 Lexus IS200t, front left. This KYB Gas-a-just strut is a direct-fit suspension service part for Lexus IS front suspension repair.

Key Features

• Monotube OE replacement design for the front left suspension position
• Separate hydraulic and high-pressure nitrogen gas chambers for responsive damping
• High gas pressure helps improve steering response
• Triple chrome plated piston rod helps reduce seal wear from fluid leakage
• Internal rebound spring included
• Built for vehicles that tow, work, or use larger, heavier tires and wheels
• Supports proper operation of electronic safety systems by maintaining suspension behavior as engineered
• Part number 551131 for accurate ordering and service matching

Product Details

KYB Gas-a-just 551131 uses a high-pressure monotube layout that separates gas and oil for consistent damping and quick response. The air-free hydraulic piston area is tuned for control, while the nitrogen gas chamber with floating piston adds firmness on demand without sacrificing normal ride comfort. For Lexus IS applications, this helps restore the designed balance of ride quality, steering feel, and body control.

This part cross-references Monroe Shocks & Struts 39132 for the same application. The KYB Gas-a-just line is positioned as an OE monotube replacement solution for drivers who want factory-style suspension behavior with added response under load.

What It Helps Address

• Excessive front-end bounce or oscillation
• Loose steering feel or delayed response
• Reduced control during braking, cornering, or lane changes
• Ride fade from worn or leaking front struts
• Suspension inconsistency on Lexus IS models with heavier wheels or demanding use

Installation Notes

Fits 2006-2016 Lexus IS350, front left; 2006-2015 Lexus IS250, front left; and 2016 Lexus IS200t, front left. Replace the suspension strut and coil spring assembly according to the manufacturer’s instructions. KYB recommends new strut mounts, part number SM5642, to reduce noise and vibration. Verify compressed length 17.34 in., extended length 20.78 in., and stroke length 3.44 in. before installation.

Quality Assurance

KYB is an OE suspension supplier, and the Gas-a-just design is built to match original monotube strut function for Lexus IS front suspension service. Part number 551131 is specified for the listed applications and dimensions.