How to Install a Line Lock? – 8 Steps You Need to Do

Written by

Charles Bolte


Vernon Hoppe 

how to install a line lock

A line lock is a kind of device that can be installed in your vehicle’s brake system; it allows the front and rear brakes to lock and work independently.

Line lock installation can be technical and requires the proper set of tools in order to achieve a functional setup.

Continue reading, as we guide you through each step and show you the things you will need before learning how to install a line lock.

Steps to Install a Line Lock


What to prepare

  • Line lock kit
  • Vacuum Brake Bleeder
  • #13 Drill Bit
  • 48 Inch Brake Line
  • Wire Benders
  • Barrel Connector Adapter
  • Line Wrench
  • Vise Grips
  • Wires For Line Lock
  • Inverted Bushing Adapters (⅛ to ¼ or ⅛ to 3/16 inch)

Step 1: Flush out the Master Cylinder and remove the brake lines


First, pop open or remove the hood of your car. You have to be able to identify where the master cylinder is located and if its front works for the front or rear brakes.

To do this, use a vacuum brake bleeder to dry out the fluid in the reservoir. Use a line wrench to unscrew the brass fittings, and take out the brake lines.

Step 2: Putting Bushing Adapters to the Brake Lines

To prevent any kind of leaks, use a bushing adapter that would perfectly fit and go with the solenoid brake lines.

Ideally, it is recommended to find a 1/8 to ¼ or 3/16 inch inverted bushing adapter.

Connect the brake lines to the adapters and make sure that they are securely in place.

Step 3: Securely Mount the Solenoid


Suppose that you have your line lock kit, it is time to mount the solenoid. Keep in mind to read through the installation instructions first.

Mount the solenoid in close proximity to the brake lines. As much as possible, position it away from components that would produce heat such as headers and exhaust pipes, as well as other moving parts.

Use a #13 Drill Bit to drill holes at the mounting position. Securely fasten the solenoid valve.

Step 4: Connecting the Brake Lines


Obtain a 48-inch brake line adapter from your local auto parts store. It should cost you around $8.

Then, customize your brake line using a wire bender so that the adapter would achieve the shape that you need for it to be connected to the solenoid and the master cylinder.

Note that the line lock should go after the proportional valve. You may refer to this wiring diagram/line lock install diagram.

The master port should be connected to the master cylinder, and the brake port should be connected to the front cylinder.

Step 5: Wire the Solenoid and Connect the Fuse Holder

Connect the solenoid’s two wires with the line lock’s activation switch using barrel adapters. The two wires, in particular, are the black ground wire and the hot wire.

Then, connect the fuse holder with the solenoid. Place the holder before the switch’s intended position.

Step 6: Mounting the Line Lock Button

Before proceeding, you must first disconnect the car battery. Mount the line lock button in a convenient position where it is easy to reach. Some people put it on the toggle switch, while others prefer the steering wheel sides. The location’s up to you.

Once you have mounted the switch to your desired position, there should now be two wires coming from the switch that would connect to the solenoid and to the power source.

An 18-22 inch gauge size should do the trick. Make sure that all connections are securely in place and that the switch is wired properly.

Step 7: Bleed the Brakes


A car with ABS (Anti-lock Brake System) should be air-bled so that the hydraulic fluid flows properly. You should start air-bleeding with the wheel farthest from the master cylinder and end with the closest.

It is essential that the seals and brake pipes are intact to avoid any leakages. Plus, refill the reservoir in the master cylinder to its appropriate fluid level for the braking system to properly function.

Step 8: Reconnecting the Battery and Turn the Engine On


Now, reconnect your car’s battery and turn the engine on so we can test the brake system. Apply the brakes and push the switch button.

Hold on to the button and then release the brake pedals. See if your wheels turn or not. If the brake doesn’t stop the wheels or the fuse burns, you need to recheck the connections.



What is a Line Lock?

A line lock, such as a Hurst Line Lock, is an electric solenoid that allows the front brakes to lock on their own without affecting the rear brakes. It is popular in drag racing and is also known as a launch controller.

How Does it Work?

So how does a line lock work? It works by keeping pressure in the front brakes and closing off their circuit. This device activates when you press down on the brake pedals and hold down the switch.

Using your car’s throttle will make burnouts easier. Releasing the switch ends the burnout.

Can You Use a Line Lock as a Parking Brake?

A line lock parking brake is not an advisable setup, since it can overheat and cease to work due to its high power demand draining the battery.

Should the Line Lock Come Before or After Proportioning Valve?

With proportioning valve in place, the line lock should come after it, as seen in the above line lock plumbing diagram.

So in this order, the wiring order should be the master cylinder, the proportioning valve, and then the line lock.

How Much Does a B&M Line Lock Cost?

You can get a B&M Launch Control Kit online for $120.56. The kit contains the solenoid, the button switch, the switch mount, the fuse, and the indicator light.

How Much Does a Manual Brake Line Lock Cost?

There are various models online, particularly on Amazon, which offers a lock for hydraulic brakes which cost $26.33.


Now that you have learned what a line lock is, its purpose, and how to install it, your vehicle can now do those burnouts and bring home the bacon on your next race.

As long as you follow the steps and have the right equipment, installing a launch controller should be a piece of cake, especially for car enthusiasts like you.

We hope that this topic on how to install a line lock was able to give you useful information as well as helpful tips to set up line lock.

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