240sx To 300zx Brake Conversion: A Big Brake Upgrade

The Nissan 240SX, a beloved sports car for its handling and potential, often finds itself in the hands of enthusiasts looking for more performance. One common and effective upgrade is improving the braking system. A popular choice is a 240SX to 300ZX brake conversion. This swap provides a significant increase in braking power, offering improved stopping distances and enhanced safety, especially when adding performance modifications like engine swaps or forced induction.

Why Upgrade Your 240SX Brakes?

The stock brakes on the 240SX, while adequate for everyday driving in its original form, often become insufficient when the car is modified for performance. Here's why an upgrade is often necessary:

Increased Power: More horsepower demands more stopping power. An engine swap or turbocharger significantly increases the car's speed, making the original brakes inadequate.
Improved Handling: Upgraded brakes allow you to brake later and harder, improving corner entry and overall track performance.
Reduced Brake Fade: Track days and aggressive street driving can cause brake fade, where the brake pedal feels spongy and stopping power diminishes. Larger brakes dissipate heat more effectively, reducing fade.
Enhanced Safety: Ultimately, better brakes improve safety. Quicker stopping distances can prevent accidents.

The 240SX to 300ZX Brake Conversion: An Overview

The 240SX to 300ZX brake conversion is a relatively straightforward and cost-effective way to upgrade the braking system. The 300ZX (Z32) brakes are significantly larger than the 240SX (S13/S14) brakes, providing a substantial improvement in braking performance. This upgrade typically involves replacing the front and rear calipers, rotors, and potentially the master cylinder. While it's generally a bolt-on affair, some minor modifications might be required depending on the specific parts used.

Parts Required for the Conversion

Before embarking on this upgrade, you'll need to gather the necessary parts. Here's a comprehensive list:

Front Brakes:

300ZX Front Calipers: Obtain a set of front calipers from a Nissan 300ZX (Z32). Ideally, get a set in good condition with minimal corrosion. Rebuild kits are readily available to ensure optimal performance. Consider the aluminum 4-piston calipers, as these offer superior performance.
300ZX Front Rotors: You'll need a pair of 300ZX front rotors. Ensure they are the correct size and fitment for your calipers. New rotors are highly recommended for optimal performance and safety.
Brake Pads: Choose a set of brake pads that match your driving style. Performance pads are recommended for track use or aggressive street driving.
Brake Lines: Stainless steel brake lines are a worthwhile upgrade, providing better pedal feel and resistance to expansion under pressure.
Caliper Mounting Bolts: Ensure you have the correct bolts to mount the 300ZX calipers to your 240SX spindles.

Rear Brakes:

300ZX Rear Calipers: Similar to the front, obtain a set of rear calipers from a Nissan 300ZX (Z32). Ensure they are in good condition.
300ZX Rear Rotors: You'll need a pair of 300ZX rear rotors. Ensure they are the correct size and fitment for your calipers. New rotors are highly recommended.
Brake Pads: Choose a set of brake pads that match your driving style.
Brake Lines: Again, stainless steel brake lines are recommended.
Parking Brake Cables: The 300ZX parking brake cables are generally needed for proper functionality of the rear brakes, as the 240SX cables are often incompatible or too short.
Rear Caliper Mounting Bolts: Ensure you have the correct bolts to mount the 300ZX calipers to your 240SX spindles.

Optional but Recommended:

300ZX Brake Master Cylinder: Upgrading to a 300ZX brake master cylinder is highly recommended. The larger bore of the 300ZX master cylinder provides more fluid volume, resulting in a firmer pedal feel and improved braking performance. Without it, you might experience a softer, less responsive pedal.
Brake Booster: While not always necessary, some choose to upgrade the brake booster to match the master cylinder for optimal performance.
Brake Proportioning Valve: Consider adjusting the brake proportioning valve to fine-tune the front-to-rear brake bias. This is especially important if you're changing the rear brake setup significantly.
Wheel Spacers: Depending on your wheels, you might need wheel spacers to clear the larger 300ZX calipers, especially in the front. Check the clearance carefully before installation.

Installation Process

The installation process is generally straightforward, but it's crucial to have a good understanding of automotive mechanics and brake systems. If you're not comfortable working on brakes, it's best to have a professional install them. Here's a general overview:

Preparation: Gather all the necessary parts and tools. Park the car on a level surface and secure it with jack stands. Disconnect the battery.
Remove Old Brakes: Remove the existing 240SX calipers, rotors, brake lines, and parking brake cables (rear).
Install Front Calipers and Rotors: Install the 300ZX front calipers and rotors. Ensure proper alignment and torque the mounting bolts to the manufacturer's specifications. Connect the new brake lines.
Install Rear Calipers and Rotors: Install the 300ZX rear calipers and rotors. Ensure proper alignment and torque the mounting bolts to the manufacturer's specifications. Connect the new brake lines and parking brake cables.
Install Master Cylinder (Optional): If upgrading the master cylinder, remove the old one and install the 300ZX master cylinder. Be careful to avoid spilling brake fluid on painted surfaces.
Bleed the Brakes: Bleed the entire brake system thoroughly to remove any air bubbles. This is a critical step for proper brake function. Start with the caliper furthest from the master cylinder and work your way closer.
Adjust Parking Brake: Adjust the parking brake cable to ensure proper engagement and disengagement.
Test Drive: After installation, perform a test drive to ensure the brakes are functioning correctly. Start with gentle braking and gradually increase the braking force. Listen for any unusual noises or vibrations.

Important Considerations

Wheel Fitment: Ensure your wheels clear the larger 300ZX calipers. You might need wheel spacers to achieve proper clearance. Measure carefully before purchasing parts.
Brake Bias: The 300ZX brakes can alter the front-to-rear brake bias. Consider adjusting the brake proportioning valve to optimize the bias for your driving style and vehicle setup. Improper brake bias can lead to instability during braking.
Brake Fluid: Use high-quality brake fluid that meets or exceeds DOT 4 specifications.
Rebuilding Calipers: Consider rebuilding the 300ZX calipers before installation, especially if they are used. Rebuild kits are readily available and relatively inexpensive. This ensures optimal performance and reliability.
Professional Installation: If you're not comfortable working on brakes, have a professional install them. Brake work is critical for safety.

Benefits of the 300ZX Brake Conversion

The 240SX to 300ZX brake conversion offers several significant benefits:

Improved Stopping Power: The larger rotors and calipers provide a larger surface area for braking, resulting in shorter stopping distances.
Reduced Brake Fade: The larger brakes dissipate heat more effectively, reducing brake fade during aggressive driving.
Enhanced Pedal Feel: A properly installed conversion with a 300ZX master cylinder provides a firmer and more responsive brake pedal.
Improved Safety: Ultimately, better brakes improve safety by providing more control and shorter stopping distances.

Alternatives to the 300ZX Brake Conversion

While the 300ZX brake conversion is a popular choice, other options are available for upgrading your 240SX brakes:

Aftermarket Big Brake Kits: Several companies offer complete big brake kits specifically designed for the 240SX. These kits typically include larger rotors, multi-piston calipers, and all necessary hardware. While more expensive, they often offer superior performance.
Z32 Rear Brake Upgrade with Aftermarket Front Calipers: This involves using the Z32 rear brake setup paired with aftermarket front calipers for a balanced braking system.
Wilwood Brake Kits: Wilwood offers a variety of brake kits for the 240SX, providing a wide range of performance options.

The best choice depends on your budget, driving style, and performance goals. Research different options and compare features and prices before making a decision. Consider your wheel size limitations as well.

Conclusion

The 240SX to 300ZX brake conversion is a worthwhile upgrade for any 240SX owner looking to improve their car's braking performance. It's a relatively affordable and straightforward way to achieve significant gains in stopping power and safety. By following the steps outlined in this article and considering the important considerations, you can successfully upgrade your 240SX brakes and enjoy enhanced performance and peace of mind.

Always prioritize safety when working on your car's braking system. If you are not comfortable performing the installation yourself, seek the assistance of a qualified mechanic.