Radflo 2.5 OE Adjustable Coilover Installation Guide for Toyota 4Runner

Quick Answer

Installing Radflo 2.5 OE adjustable coilovers on your Toyota 4Runner is a straightforward job if you have basic mechanical skills and the right tools. Follow this guide to ensure a safe, correct installation, and remember to adjust the coilovers to your desired ride height before mounting them.

If you're looking to improve your Toyota 4Runner's off-road capability and on-road comfort, the Radflo 2.5 OE adjustable coilovers are a solid choice. These coilovers let you fine-tune your front suspension to match your driving style and terrain. This guide walks you through the installation process, from prep to final adjustments.

Before you start, gather the necessary tools: a floor jack, jack stands, wrenches, sockets, a torque wrench, spring compressors, and safety glasses. Also, have the vehicle's service manual handy for torque specifications. If you're not confident in your abilities, consider having a professional install the coilovers.

Preparation and Safety

Start by parking your 4Runner on a flat, level surface and engaging the parking brake. Loosen the lug nuts on the front wheels, then use a floor jack to lift the front of the vehicle and support it securely with jack stands. Never work under a vehicle supported only by a jack.

Before removing anything, spray penetrating oil on the lower strut bolts and any other fasteners that might be seized. This will make removal easier and reduce the risk of breaking bolts. Also, take note of the original ride height and alignment settings so you can return to them if needed.

• Check that all necessary parts are included: coilovers, hardware, and any spacers or instructions.
• If you plan to adjust the coilover spring preload, do it before installation to save time.

Removing the Factory Struts

With the wheel removed, disconnect the sway bar end link from the lower control arm. Then, remove the brake line bracket from the strut to give yourself room. Support the lower control arm with a jack to keep it from dropping when you remove the strut.

Remove the two or three nuts holding the top of the strut to the strut tower. Then, remove the lower bolts that secure the strut to the steering knuckle. Carefully pull the strut assembly out. Watch for any corrosion or stuck bolts; if they resist, use a breaker bar or impact wrench.

• Keep all hardware organized in a labeled bag.
• Do not force the strut out; if it's stuck, check for hidden bolts or clips.

Installing the Radflo 2.5 OE Adjustable Coilovers

Before installation, compare the new Radflo coilover with the factory unit to ensure it's the correct application. Set the spring preload and ride height according to your desired lift—Radflo OE adjustable coilovers allow you to adjust the spring perch to achieve the height you want.

Install the new coilover into the strut tower, ensuring the top nut is snug but not fully tightened. Then, attach the lower end to the steering knuckle. Torque the lower bolts to factory specifications. Reconnect the sway bar end link and brake line bracket. Finally, tighten the top nuts to spec.

• Double-check that the coilover is oriented correctly; the reservoir hose should not be kinked or rubbing against anything.
• Use a torque wrench for all critical fasteners to avoid over-tightening or under-tightening.

Setting Ride Height and Preload

Radflo 2.5 OE adjustable coilovers let you fine-tune the ride height by adjusting the spring preload. To do this, loosen the jam nut on the spring perch and turn the perch to compress or relax the spring. Increasing preload raises the vehicle; decreasing it lowers the vehicle. Always adjust both sides equally to keep the vehicle level.

After setting your desired height, torque the jam nut to spec. Remember that changing preload affects alignment, so you'll need a professional alignment after installation. Also, check that the coilover's adjustment range stays within the manufacturer's recommended limits to avoid coil bind or bottoming out.

• Measure from the center of the wheel to the fender lip to verify equal height on both sides.
• Make small adjustments (1/4 turn) and recheck before moving on.

Reassembly and Final Checks

With both coilovers installed, reinstall the wheels and lower the vehicle to the ground. Before driving, cycle the suspension by pushing down on the front bumper a few times to settle the suspension. Then, check all bolts again for proper torque.

Take the vehicle for a short test drive, listening for any unusual noises. Check for clearance issues by turning the wheels fully left and right. If everything feels good, schedule a professional alignment to set camber, caster, and toe to factory specs.

• After a few hundred miles, re-torque the coilover mounting bolts and check the spring preload settings.
• If you notice excessive vibration or noise, inspect the installation for loose parts or interference.

Step-by-Step Installation Checklist

1. Prepare the vehicle: Park on level ground, engage parking brake, loosen lug nuts, lift and support on jack stands, and spray penetrating oil on bolts. Check: Vehicle is stable and all fasteners are accessible.
2. Remove factory struts: Disconnect sway bar links, brake lines, and top strut nuts. Support lower control arm, then remove lower bolts and pull strut assembly. Check: No hidden clips remain; keep hardware organized.
3. Install Radflo coilovers: Set preload and ride height, then install into strut tower and attach to knuckle. Torque all bolts to spec. Check: Coilover orientation correct; no kinked hoses.
4. Adjust ride height and preload: Loosen jam nut, turn spring perch to desired height, re-tighten jam nut. Adjust both sides equally. Check: Vehicle sits level; adjustments within manufacturer limits.
5. Reassemble and test: Reinstall wheels, lower vehicle, cycle suspension, check torque, test drive, and get a professional alignment. Check: No noises or clearance issues; re-torque after 500 miles.

Related Products at Shock Surplus

• King Shocks 2.5 Performance Coilovers w/ Adjustable Remote Reservoir + Rear Adj Reservoir Shocks Set for 2025-2026 Toyota 4Runner 4WD RWD w/2-2.5: Upgrade your 2025-2026 Toyota 4Runner with this complete King Shocks suspension set, featuring 2.5 Performance Coilovers with adjustable remote reservoirs up front and rear adjustable reservoir shocks. If you're considering a high-end alternative to Radflo, this King Shocks set offers remote reservoir adjustability and is designed specifically for the latest 4Runner models.
• 6112 Assembled Set includes 5100/5160 Shocks for 2010-2024 Toyota 4Runner: Thyssenkrupp Bilstein of America warrants its gas pressure shock absorbers against defects in workmanship and materials for as long as you, the original purchaser, own your car. For a budget-friendly option, this Bilstein set provides a complete front and rear solution with a lifetime warranty, making it a strong alternative to Radflo coilovers.

Installing Radflo 2.5 OE adjustable coilovers on your Toyota 4Runner can dramatically improve ride quality and off-road performance. By following these steps and paying attention to adjustment details, you'll ensure a successful installation. Always prioritize safety and don't skip the alignment.