2015 Lexus IS350 F Sport Suspension Part Diagram: A Complete Guide

The 2015 Lexus IS350 F Sport offers a performance-oriented suspension that blends comfort with handling. Understanding its parts and how they connect is essential for maintenance, repair, or aftermarket upgrades. This guide breaks down the suspension part diagram, explains each component's role, and provides practical insights for owners.

Front Suspension Overview

The front suspension of the 2015 IS350 F Sport uses a MacPherson strut design with aluminum components to reduce unsprung weight. Key parts include the strut assembly, lower control arm, stabilizer bar, and steering knuckle.

Strut Assembly

The front strut integrates the coil spring and shock absorber. The F Sport version features a tuned damper for better response. Common part numbers include 48510-79A00 (left) and 48510-79A10 (right). The top mount includes a bearing that allows steering rotation.

Lower Control Arm

This aluminum arm connects the steering knuckle to the subframe. It houses a front bushing (typically fluid-filled) and a rear bushing. The ball joint is integrated into the arm. Part numbers vary: 48630-79A00 (left) and 48610-79A00 (right).

Stabilizer Bar

The front sway bar (part 52321-79A00) is 26mm thick and links the control arms via end links (part 48820-79A00). It reduces body roll during cornering.

Steering Knuckle

This casting connects the strut, lower control arm, tie rod, and wheel bearing. The F Sport knuckle is identical to the standard IS350 but may have different part numbers due to brake caliper mounting.

Rear Suspension Overview

The rear uses a multilink setup with separate upper and lower control arms, a toe-control arm, and a stabilizer bar. This design provides camber adjustability.

Upper Control Arm

The rear upper arm is an aluminum forging (part 48710-79A00). It mounts to the subframe and knuckle, with bushings at both ends.

Lower Control Arm

The lower arm (part 48730-79A00) is also aluminum and supports the spring seat. The coil spring sits between the arm and the subframe.

Toe Control Arm

This arm (part 48740-79A00) adjusts rear toe alignment. It connects the subframe to the knuckle and has an eccentric bolt for adjustment.

Stabilizer Bar

The rear sway bar (part 52321-79A10) is 18mm thick with end links (part 48830-79A00).

Diagram Interpretation

When viewing a diagram, note the following conventions:

• Arrows indicate torque specifications or tightening sequences.
• Rubber bushings are often shown as crosshatched ovals.
• Ball joints appear as circles with a dot in the center.
• Threaded holes with bolts are common; pay attention to fastener grades.

Factory service diagrams typically break the suspension into these sections:

• Front: Strut, lower arm, stabilizer, and knuckle.
• Rear: Upper arm, lower arm, toe arm, and stabilizer.

Common Replacement Parts

Some components wear faster. Consider these:

• Struts: F Sport struts often leak after 60,000-80,000 miles. Replace with OEM or performance coilovers.
• Control Arm Bushings: Front lower rear bushing (part 48632-79A00) is a known failure point. Polyurethane replacements increase stiffness.
• End Links: Stabilizer bar end links wear, causing clunks. Aftermarket options use greasable joints.
• Ball Joints: Not separately serviceable on front lower arms; replace entire arm.

Practical Usage Guidance

If you're planning to replace suspension parts, note these tips:

• Use an alignment after any control arm or strut replacement.
• Torque all fasteners with the suspension under load (car on wheels) to prevent bushing preload.
• Compatible aftermarket brands include KYB (struts), Moog (control arms), and Energy Suspension (bushings).
• Part numbers listed are OEM; cross-reference with catalogs for aftermarket equivalents.

Final Recommendation

For DIY owners, start by obtaining a factory workshop manual or a reputable suspension diagram specific to the 2015 IS350 F Sport. Identify the worn component by symptom (noise, vibration, or uneven tire wear). Replace in pairs (both front struts, both rear upper arms) to maintain balance. If upgrading, consider coilover kits that replace the entire strut assembly for improved adjustability. Always pair new parts with fresh fasteners and perform a professional alignment afterward.