Brake Hydraulic Line Lock Kit
What Is a Brake Hydraulic Line Lock Kit?
A brake hydraulic line lock kit is one of the most essential tools in a performance driver's arsenal. At its core, a line lock is an electrically controlled solenoid valve that installs inline in your brake hydraulic circuit. These kits allow the front brakes to lock independently of the rear brakes via a switch — meaning you can hold the car stationary at the front while the rear wheels spin freely. The result: a fully controlled burnout to heat your tires for maximum traction, or a clean, staged launch without rolling through the timing beams.
How Does a Hydraulic Line Lock Work?
The mechanism is straightforward but ingenious. When you press the brake pedal to build hydraulic pressure and then activate the line lock switch, the solenoid closes off the front brake circuit, trapping that pressure and keeping the front wheels locked. You can then release the brake pedal — the front brakes stay engaged, but the rear brakes release, freeing the drive wheels to spin. When you're ready to launch, releasing the switch instantly opens the solenoid and frees the front wheels for a clean getaway.
For manual transmission cars, this is especially critical. Launching requires simultaneous clutch and throttle inputs, leaving no foot free for the brake pedal. A line lock solves that problem by holding the car stationary with the front brakes while the driver manages the clutch and gas. On automatic transmission cars, it lets the engine rev to peak power RPM for a more aggressive, consistent launch.
What to Consider When Shopping for a Line Lock Kit
- Universal vs. Vehicle-Specific: Some kits come with pre-bent, direct-fit brake lines for popular platforms like the Ford Mustang, making installation clean and straightforward. Universal kits offer flexibility for custom or less-common builds.
- Solenoid Construction: Look for stainless steel valve assemblies and epoxy-molded or waterproof coils for long-term durability under the heat and vibration of repeated track use.
- Release Time: In drag racing, where hundredths of a second matter, a line lock's release time is crucial. Top-tier kits are engineered for near-instantaneous response.
- Included Components: A complete kit should include the solenoid valve, activation switch, indicator light, fuse, and mounting hardware. Some kits also include a separate port for a brake pressure gauge — a handy feature for dialing in your setup.
- Rebuildability: Field-serviceable solenoids let you clean and rebuild the unit rather than replace it, saving money over a racing season.
Top Brands in Brake Hydraulic Line Lock Kits
Hurst is the most recognized name in line lock technology, with their legendary Roll/Control® system setting the benchmark for the category. Known for their finned aluminum housing that helps dissipate heat, stainless steel valve assemblies, and 150-micron screen-filtered ports, Hurst offers both universal and vehicle-specific kits to cover a wide range of applications.
B&M brings its deep drag racing heritage to the line lock market, offering launch control solutions that can manage either the front or rear brake circuit depending on your drivetrain configuration — available as complete kits or standalone units for those who already have some hardware in place.
Biondo Racing is a brand with proven drag strip credentials, and their line lock units reflect that pedigree. Their units feature waterproof coils, built-in mounting tabs for easy installation, and high-flow ports rated at 3,000 psi, all in a rebuildable design built for years of reliable track service.
Granatelli Motor Sports offers their Tyre Fryer line lock kits for racers who demand a rebuildable nickel-plated solenoid valve with stainless steel inserts and shifter-mountable activation switches. Their kits are engineered for a wide 12–24V operating voltage range, making them adaptable across a variety of vehicle electrical systems.