ICON Vehicle Dynamics Rear Hydraulic Air Bump Stop Kit for Toyota 4Runner / FJ Cruiser / Lexus GX

The ICON Vehicle Dynamics Rear Air Bump Stop Kit (SKU 56104) is a bolt-in hydraulic and pneumatic bump stop upgrade for the 2003–2024 Toyota 4Runner, 2007–2014 Toyota FJ Cruiser, and 2003–2023 Lexus GX, replacing the factory rubber bump stops with a velocity-sensitive unit that absorbs more energy the harder it is hit. Vehicles with factory rear air suspension require a separate rear coil conversion before this kit can be installed.

Shipping: ICON parts ship direct from ICON Vehicle Dynamics, mostly by UPS Ground. Lead times vary by part and some items are built to order, so please allow extra time. We email tracking as soon as your order ships.

Velocity-Sensitive Energy Absorption

OEM rubber bump stops release absorbed energy in an uncontrolled burst on rebound, producing the sharp rear-end kick familiar to anyone who has pushed a 4Runner or GX hard over rough terrain. The ICON hydraulic bump stop is velocity sensitive: the faster it is engaged, the more energy it absorbs. That means the harshest g-outs and square-edged hits (the ones most likely to unsettle the rear end) are also the ones this kit addresses most aggressively, rather than least.

Linear-Digressive Piston and Infinite Tuning Range

The kit uses a linear-digressive piston, which ICON states complements bump stop duty better than the industry-standard linear-linear piston by providing a more progressive resistance curve as the stop is compressed. For owners who want to go further, the kit supports infinite tuning through three adjustable levers: valve stack, oil volume, and nitrogen pressure. The bump stops are fully rebuildable and user-serviceable, so the investment is not a single-use consumable.

Bolt-In Fit with No Loss in Travel

The kit installs inside the existing rear coil with no modification to the coil perch or shock mount, and ICON states there is no loss in suspension travel compared to the stock configuration. A CAD-plated body provides corrosion resistance, and a urethane rod seal and wiper are included for long service life. The bump stops arrive pre-tuned for most users, so the kit is functional immediately after installation without requiring a custom valving session.

Features

• Velocity-sensitive design: energy absorption increases proportionally with impact speed
• Linear-digressive piston: provides a progressive resistance curve suited to bump stop use
• No travel loss: installs inside the coil without reducing suspension travel
• CAD-plated body: corrosion-resistant finish for long-term durability
• Urethane rod seal and wiper: included for extended service life
• Rebuildable and tunable: valve stack, oil volume, and nitrogen pressure adjustable; user-serviceable

Specifications

Who This Is For and Isn't

This kit suits 2003–2024 Toyota 4Runner, 2007–2014 Toyota FJ Cruiser, and 2003–2023 Lexus GX owners who experience harsh rear-end behavior over rough terrain and want a rebuildable, tunable hydraulic bump stop that installs inside the stock coil without reducing travel.

This kit does not install directly on vehicles equipped with factory rear air suspension; those applications require ICON rear coil conversion kit (p/n 56110) and compatible ICON rear coil springs (p/n 52700 or 52800) as separate purchases before this kit can be used.

Common Questions

Will this kit work with my factory rear air suspension?

The ICON Rear Air Bump Stop Kit (SKU 56104) does not install directly on vehicles with factory rear air suspension. Those vehicles require ICON's rear coil conversion kit (p/n 56110) and ICON rear coil springs (p/n 52700 or 52800) before this bump stop kit can be fitted.

Does installing this kit reduce rear suspension travel?

No. The ICON Rear Air Bump Stop Kit installs inside the existing rear coil and is designed to provide no loss in suspension travel compared to the stock configuration.

Can I tune or rebuild these bump stops myself?

Yes. The ICON Rear Air Bump Stop Kit is fully rebuildable and user-serviceable, with tuning available through valve stack, oil volume, and nitrogen pressure adjustments. The kit ships pre-tuned for most users and does not require custom valving to be functional out of the box.

What vehicles does this bump stop kit fit?

The ICON Rear Air Bump Stop Kit (SKU 56104) fits the 2003–2024 Toyota 4Runner, 2007–2014 Toyota FJ Cruiser, and 2003–2023 Lexus GX. This part number is not listed for any other vehicle fitment.