How do I route the brake lines for a Wilwood brake kit on a Mazda RX-7 FC?

Routing brake lines for a Wilwood kit on an FC RX-7 requires careful attention to suspension movement. Because the FC uses a MacPherson strut front suspension (unlike the double-wishbone FD), the entire strut assembly turns with the steering. If you don't route and secure the lines correctly, they will rub against the tire, snag on the suspension, or pull out of the fittings.

Difficulty: Moderate
Safety Warning: Always use appropriately rated jack stands. Brake fluid destroys paint, so keep rags and brake cleaner handy. You are working on a critical safety system; if a line rubs through while driving, you will lose braking on that circuit.

Here is the standard practice for routing aftermarket braided lines on the FC chassis:

Front Line Routing

1. Connect the Chassis Side: Thread the new line into the factory hardline fitting on the inner fender well. Use a flare nut wrench to avoid rounding the hardline fitting.
2. Route to the Caliper: The line needs to arc down to the Wilwood caliper. Pay close attention to the fitting angle at the caliper itself. Depending on how your specific kit was pieced together, it may use straight, 45-degree, or 90-degree fittings. Make sure the fitting is oriented so the line naturally points up toward the chassis without kinking or forcing a hard bend that could contact the strut at full lock, which is a known headache on some RX-7 Wilwood setups ³.
3. Secure to the Strut: This is the most critical step. The line must be secured to the strut body so it moves with the wheel. If your Wilwood lines do not have a built-in locating block or clip to attach to the factory FC strut bracket, do not leave them hanging. A standard community workaround used on RX-7 big brake kits is to slide a split rubber sleeve (like a piece of vacuum or fuel hose) over the braided line to act as an insulator, then tightly zip-tie that sleeved section to the factory shock mount ⁴. This prevents the stainless braiding from chafing against the metal bracket.

Rear Line Routing

The rear is much simpler because the independent rear suspension only moves vertically; the wheels don't steer.

1. Route the line from the chassis hardline down to the trailing arm/caliper.
2. Ensure the line is routed away from the half-shafts and doesn't bow outward where it could rub the inside barrel of your wheel.
3. Secure it to the factory trailing arm bracket using the same rubber sleeve and zip-tie method if the line lacks a factory-style retaining clip.

The Clearance Test (Mandatory)

Before bleeding the system, you must verify clearance:

1. With the car still safely on jack stands, bolt the front wheels on.
2. Have a helper turn the steering wheel slowly from full lock left to full lock right.
3. Get under the car with a flashlight and watch the front lines. They should have enough slack to accommodate full steering lock and full suspension droop without pulling tight, but not so much slack that they bow out and touch the tire sidewall or the inner fender.
4. Adjust the slack at your zip-tie/mounting points as needed until the arc is clean and safe throughout the entire range of motion.