IS300 Rear Knuckle Bushing Install | Polyurethane & Spherical Upgrade

Upgrading your IS300’s suspension is one of the most rewarding things you can do to improve handling, control, and overall performance. One key upgrade? Rear knuckle bushings! In this guide, we’re going to walk you through the process of removing the two rear knuckle bushings in your IS300 and replacing them with high-quality polyurethane and spherical bushings.

These upgraded bushings are designed to minimize play, especially under heavy loads or during intense braking. This ensures your car stays under precise control at all times, making it a must-have for anyone looking to improve the driving experience of their IS300, whether it’s for daily driving or spirited driving on the track.

Why Upgrade to Polyurethane and Spherical Bushings?

Upgrading to polyurethane and spherical bushings offers several benefits over stock rubber bushings:

• Reduced Suspension Play: Polyurethane bushings provide better control, reducing the amount of movement that occurs in the rear knuckle under heavy loads and braking.

• Improved Handling & Control: These bushings stiffen up the suspension and improve the overall response of your IS300, making it feel more precise and planted.

• Durability: Unlike rubber, polyurethane and spherical bushings last longer and are less susceptible to wear, heat, and environmental damage, meaning they’ll keep performing at a high level for a longer time.

Tools You’ll Need:

• Hydraulic jack and jack stands

• Socket set

• Impact wrench (optional, but helps speed up bolt removal)

• Bushing press or appropriate tool for bushing removal

• Hammer (for stubborn bushings)

• Pry bar

• Torque wrench

• Polyurethane and spherical bushings (make sure to get a high-quality set designed for the IS300 from Lunatics Co.)

• Bushing press kit (recommended for easy removal and installation)

Step-by-Step: Removing the Rear Knuckle Bushings

1. Lift the Car and Secure It
   Start by raising the rear of your IS300 with a hydraulic jack. Secure the car with jack stands to ensure safety while you’re working.

2. Remove the Rear Wheels
   Take off the rear wheels to expose the suspension components you’ll be working on.

3. Unbolt the Rear Knuckle
   Locate the bolts holding the rear knuckle in place and use your socket set to remove them. These bolts can be tight, so make sure to apply some force if necessary.

4. Remove the Old Bushings
   Once the knuckle is free, you’ll need to remove the old bushings. If you’re using a bushing press, follow the manufacturer’s instructions to press out the old bushings. If you're doing this by hand, you can use a hammer and pry bar to gently tap and remove the bushings. Be cautious not to damage the knuckle during removal.

Step-by-Step: Installing Polyurethane and Spherical Bushings

1. Prep the New Bushings
   Take your new polyurethane and spherical bushings and ensure they’re properly greased (if required). Polyurethane bushings often come with grease for easier installation and smoother performance.

2. Press in the New Bushings
   Using the bushing press or a similar tool, carefully press the new bushings into the knuckle. Make sure they’re aligned properly and seated firmly.

3. Reinstall the Rear Knuckle
   Once the new bushings are in place, it’s time to reinstall the knuckle back onto the car. Align the knuckle properly and rebolt it to the suspension components.

4. Reattach the Rear Wheels
   After everything is securely in place, put the rear wheels back on and torque the lug nuts to the manufacturer’s specifications.

5. Lower the Car and Test Drive
   Lower your IS300 back to the ground, and be sure to give everything a once-over to ensure that all bolts and components are tight. Take the car for a test drive to ensure the rear suspension feels tight and responsive.

That’s it! The process of removing and installing the rear knuckle bushings on your IS300 is straightforward, and with the right tools and a little patience, you can significantly improve the handling and performance of your car. Whether you're a seasoned pro or a DIY enthusiast, this upgrade is a great way to enhance your IS300’s driving experience.

Common Challenges to Keep in Mind:

• Stubborn Bushings: If you run into any stubborn old bushings, don’t hesitate to use extra force with the bushing press or even a hammer, but do so carefully to avoid damaging the knuckle.

• Aligning the Knuckle: Be mindful when reinstalling the knuckle to ensure proper alignment of all components to avoid any suspension issues.

For more helpful tips, tricks, and IS300 maintenance tutorials, check out the full list of videos and guides on my channel. Don’t forget to subscribe and stay tuned for more!