Installing an AP Racing hydraulic handbrake is one of the most effective upgrades you can make to a track car, especially if you drift, rally, or need precise rear-wheel lockup for tight turns. Unlike a factory cable handbrake, a hydraulic system uses brake fluid to actuate the rear calipers directly, giving you consistent, powerful control at any speed. However, a proper installation is critical—sloppy mounting, leaking lines, or air in the system can compromise safety and performance. This guide covers everything from kit selection to final testing, so you can get your AP Racing handbrake working flawlessly on the track.

Understanding Hydraulic Handbrakes vs. Cable Handbrakes

Before diving into installation, it helps to understand why a hydraulic handbrake is preferred for competition. A cable handbrake relies on a mechanical linkage that can stretch, bind, or lose leverage over time. Hydraulic systems, by contrast, use fluid pressure to engage the rear brakes directly from the handbrake master cylinder. This provides a more immediate, consistent feel and allows you to modulate lockup with finer control.

AP Racing’s handbrakes are built with a compact master cylinder and a lever assembly that can be configured for either push or pull operation. Most track users choose a pull-style lever mounted between the seats or on the transmission tunnel. The key advantage is repeatable lockup without fading—ideal for repeated drift entries or for managing weight transfer in tight hairpins.

If you're currently running a stock cable handbrake, switching to hydraulic will require adding a dedicated handbrake master cylinder and plumbing it into the rear brake circuit. Many AP Racing kits come with a pre-assembled lever and cylinder, plus the necessary fittings, but you’ll still need to install it correctly to avoid leaks or air intrusion.

Choosing the Right AP Racing Handbrake Kit

AP Racing offers several handbrake models, each with different lever ratios and master cylinder sizes. The most common for track cars are the CP5277 and CP5278 series. The CP5277 uses a 0.625-inch bore master cylinder and a 4:1 lever ratio, which provides a good balance of effort and stroke for most applications. The CP5278 has a 0.700-inch bore for higher fluid displacement, often used on cars with larger rear calipers or when additional travel is needed.

Consider these factors when selecting:

  • Rear caliper piston area: Larger calipers need more fluid volume, so choose a larger master cylinder bore.
  • Lever length and mounting space: Measure your cockpit area to ensure the lever clears seats, shifters, and your legs.
  • Ratchet vs. non-ratchet: Some AP Racing kits include a ratchet mechanism to hold the lever engaged—useful for hill climbs or stationary parking, but add weight and complexity.

For most amateur track cars with sliding or small four-piston rear calipers, the CP5277 is ideal. If you're unsure, consult AP Racing’s official product guide at AP Racing Handbrake Range for detailed specs.

Preparing for Installation

Tools and Materials

Gather everything before you start to avoid mid-job trips to the hardware store. You’ll need:

  • AP Racing hydraulic handbrake kit (lever, master cylinder, mounting bracket, fittings)
  • Metric and SAE wrenches/sockets (typically 10mm, 12mm, 13mm, and 17mm for fittings)
  • Drill with metal bits (pilot drill + final size for mounting bolts)
  • Brake fluid (DOT 4 or 5.1, never DOT 5 silicone)
  • Brake line tubing (usually 3/16-inch copper-nickel or stainless steel for hard lines; AN-3 or AN-4 for flexible braided lines)
  • Flare tool if you are making custom hard lines
  • Brake bleeder kit (one-way valve or pressure bleeder)
  • Safety glasses, gloves, and a fire extinguisher nearby

Also have a helper available for bleeding and for holding the lever during mounting.

Workspace and Safety

Work on a level surface, chock the wheels, and disconnect the battery if you’ll be near any electrical components. Brake fluid is corrosive to paint and plastic, so cover the interior carpets and center console with old towels. Keep a container of water nearby to flush any spills immediately.

Selecting the Mounting Location

Mounting position directly affects ergonomics and activation speed. In a track car, the hydraulic handbrake is usually placed on the transmission tunnel, between the driver and passenger seats, or beside the shifter for easy reach. AP Racing brackets often use the OEM handbrake mounting points, but many installations require drilling new holes into the tunnel or a custom bracket.

Evaluate these criteria for your chosen spot:

  • Driver reach: With your harness on and helmet strapped, you should be able to pull the lever fully without straining your arm or shoulder.
  • Clearance from pedals and legs: Ensure the lever doesn’t hit your knees when you pull it, especially if you are tall or have a fixed seat position.
  • Clearance from shift linkage and wiring: Avoid areas where the lever can contact shift cables, handbrake cables (if you’re keeping the rear cable as backup), or electrical harnesses.
  • Structural backing: The mounting surface must be strong enough to handle repeated forces. If you’re drilling into thin sheet metal, reinforce the underside with a steel plate.

Mock up the handbrake using painter’s tape or clamps before drilling. Sit in the driver’s seat and simulate pulling the lever through its full travel. Adjust the position until it feels natural and then mark the mounting holes with a center punch.

Step-by-Step Installation

Drilling and Mounting

Once you’ve marked the holes, drill pilot holes first, then enlarge to the final bolt size. Use a drill stop or masking tape on the drill bit to prevent punching through into wiring or the underside of the tunnel. Clean any metal shavings thoroughly.

Apply a thin layer of anti-seize to the bolts to ease future removal. Use flat washers and lock washers or thread-locker (Loctite 243) on all mounting bolts. Torque to the specification in your AP Racing kit manual—typically 15–20 Nm for M8 bolts. If your kit didn’t come with a mounting bracket, companies like OBD2Tool offer universal brackets, but a custom plate from a local machine shop is often cleaner.

Connecting the Master Cylinder

The AP Racing handbrake master cylinder will have an inlet port (for fluid from the reservoir) and an outlet port (to the rear brake circuit). Some kits have a built-in reservoir; others rely on an external remote reservoir. Follow the kit’s orientation instructions—the lever must push the master cylinder piston squarely to avoid binding.

If using a remote reservoir, mount it higher than the master cylinder to allow gravity feed and simplify bleeding. Use a rubber grommet or bulkhead fitting where the hose passes through metal panels to prevent chafing.

Hydraulic Line Routing and Connection Tips

The handbrake must be plumbed into the rear brake circuit in series with the existing rear calipers. Typically, the line from the brake master cylinder’s rear outlet goes to the handbrake master cylinder’s inlet, then from the handbrake outlet to the rear calipers. This allows the foot brake to push fluid through the handbrake when the lever is not engaged, and the lever to increase pressure independently.

Use AN-3 or AN-4 braided stainless steel lines for flexibility—they resist heat and vibration better than rubber. If you prefer hard lines, use copper-nickel (cunifer) for its ease of flaring and corrosion resistance. Never reuse old rusty lines; they can burst under the higher pressures a handbrake creates.

When routing lines:

  • Avoid contact with hot exhaust components (turbo downpipe, exhaust manifold, catalytic converter).
  • Use rubber-lined P-clips or Adel clamps to secure the line every 12 inches.
  • Keep lines away from sharp edges—debur any holes or brackets where the line passes.
  • Use a slight loop or bend at the master cylinder connection to absorb vibration.

For a detailed guide on making double flares, check this resource: Double Flare Tool Instructions. Professional flare quality is important—a poor flare will leak under pressure.

Once all connections are tight, fill the handbrake reservoir with fresh DOT 4 fluid. Do not use DOT 5 silicone fluid—it compresses and gives a spongy feel.

Bleeding the Hydraulic Handbrake System

Bleeding a hydraulic handbrake is similar to bleeding a clutch or brake circuit, but requires extra attention because the handbrake circuit is separate from the foot brake circuit. Air can get trapped in the handbrake master cylinder or in the line between it and the rear calipers.

The most effective method uses a pressure bleeder set to 10–15 psi, but a two-person manual bleed works fine:

  1. Jack up the rear of the car securely and remove the rear wheels for easy access to the caliper bleeders.
  2. Connect a clear hose to the right-rear caliper bleeder screw (farthest from the handbrake in many layouts) and immerse the other end in a jar with fluid to prevent air being sucked back in.
  3. Have your helper slowly pull the handbrake lever to full travel and hold it.
  4. Open the bleeder screw about 1/4 turn—fluid and air bubbles will exit. Close the bleeder before the lever is released.
  5. Release the lever. Repeat until no bubbles appear.
  6. Repeat on the left-rear caliper.
  7. Now bleed the handbrake master cylinder itself if it has a separate bleeder. Many AP Racing cylinders have a small bleeder on the banjo bolt or end cap. Open it while pulling the lever until pure fluid comes out.
  8. Top off the reservoir frequently to avoid running dry.

If you still get a spongy lever after multiple attempts, try “bench bleeding” the handbrake master cylinder off the car. This removes trapped air that won’t migrate upward. Hold the master cylinder in a vice, fill it with fluid, and push the piston by hand while blocking the outlet with a thumb—release suddenly to force air out. Reinstall and repeat the on-car bleed.

For DOT 4 and 5.1 fluid, proper bleeding is essential because air degrades clutch and brake performance quickly. After bleeding, check for any fluid leaks at all fittings.

Testing and Adjusting the Handbrake

With the system bled and every connection dry, it’s time for functional testing. First, test without moving the car: pull the handbrake lever with the engine off. The lever should feel firm after 1–2 inches of travel. If it feels spongy, there’s still air—go back to bleeding.

Next, start the engine and test on level ground. With the car in neutral, pull the handbrake while gently revving the engine (if the rear wheels are off the ground you can test lockup). Then take the car to an empty parking lot and drive slowly. Pull the lever at low speed to verify that the rear wheels lock consistently. Adjust the handbrake cable or lever position if necessary:

  • Lever travel adjustment: Most AP Racing handbrakes have an adjustable stop or a pushrod length adjustment to set the point where the master cylinder begins to pressurize. Reduce free play by turning the stop screw in small increments.
  • Bleed again after adjustment: Changing pushrod position can introduce air into the master cylinder, so re-bleed after any adjustment.

Also verify that the handbrake releases fully. If the lever doesn’t return to its resting position, the brake pads will drag, causing overheating and uneven wear. Check that the lever pivot is lubricated (white lithium grease) and that there’s no binding in the master cylinder linkage.

For a more in-depth explanation of handbrake setup for drifting, Drifted.com’s handbrake setup guide offers additional tips.

Maintenance and Upkeep

Hydraulic handbrakes require more attention than cable units because fluid and seals are sensitive to heat and age. After each track day, inspect the system:

  • Check the fluid level in the handbrake reservoir—low level often indicates a leak.
  • Look for fluid weeping at fittings, banjo washers, and the master cylinder seal area. Copper washers should be replaced after every removal.
  • Test for firmness—if the lever becomes progressively spongy during a session, flush the fluid (it may have boiled if you use DOT 3 fluid). AP recommends DOT 4 or 5.1 with a dry boiling point above 500°F.
  • Replace the brake fluid every 6 months or before the start of each race season. Brake fluid absorbs moisture, lowering its boiling point.
  • Inspect the master cylinder pushrod and pivot pin for wear—replace if there is grooving or slop.

If you drive your track car on public roads, be aware that some jurisdictions require a separate mechanical parking brake. In such cases, keep your factory cable handbrake for parking and use the hydraulic handbrake only for track use. Always verify local regulations before making permanent modifications.

Conclusion

A properly installed AP Racing hydraulic handbrake transforms how you control your track car’s rear end in low-speed corners, drifts, and precision maneuvers. The key to repeatable performance lies in meticulous preparation, robust mounting, leak-free plumbing, and thorough bleeding. By following the tips outlined above—selecting the correct kit, reinforcing your mounting location, routing lines away from hazards, and bleeding the system to perfection—you’ll get a handbrake that feels crisp, reliable, and ready for the toughest sessions.

Invest the time to adjust lever travel and test on-site before your first competitive event. Once you experience the confidence of a fingertip-controlled hydraulic lockup, you’ll wonder why you didn’t make the switch sooner. For official documentation and spare parts, refer to AP Racing’s official website.