How to Install Line Lock
While I was re-doing my entire brake setup on my '54 Belair, swapping master cylinders and running new hard lines, I decided to add another little fun button to the car. A Hurst Roll Control with Stainless Steel Valve.
I am installing this on just the front brakes so I can hold the front tires with the calipers allowing the rear brakes to remain free. This allows for long, smokey, tire ruining burnouts. The main function of this would be to hold the car in place on the starting line of a drag strip. It would allow the driver to achieve an RPM level with the vehicle for ultimate launch and not roll through the timing lights causing a Red Light and lose the race before it even starts. This also holds the vehicle in place in the water box behind the starting line to heat up the tires by doing a burnout. Getting the tires hot and sticky allows more traction than a cold tire off the line. There is a time hopefully in the future I will be hitting a local drag strip, so I figured, why not add this little gem now just for fun.
This Line Lock has multiple ways to lock the brakes on your vehicle. It allows you to lock the front brakes only, the rear brakes only, or lock all four corners. Another nice feature is you can add a brake light pressure switch right into the housing of the valve to simplify wiring in brake lights.
First off, I chose a location on the firewall away from any heat source such as exhaust to mount the valve using the supplied 1/4-inch sheet metal screws. I chose to mount mine right below the booster off to the driver’s side. Once mounted, I determined what adapters I needed to run new hard lines from the master cylinder to the valve. For these, I chose Speedway Motors part number 91031833, 90-degree 3/8"-24 to 1/8" NPT male adapters. One for input from the front port on the master cylinder and one for exiting to my front brake lines. The valve body has 1/8" NPT threads so attaching my 3/16-inch brake line would require a 3/8"-24 IFF for the tube nut to screw into and seal. With the 1/8-inch pipe side of the fitting wrapped in Teflon tape for sealing, I screwed them into the appropriate ports on the valve. Inlet is on the top/front and the outlet to for the front brakes is on the left side when facing the valve. The right side of the valve I used to locate a brake light switch, Speedway Motors part number 91031304.
With the valve mounted and adapters oriented how I wanted the 90-degree ports to face I used Speedway Motors 25-foot roll of 3/16-inch steel brake line part number 91031810 along with Speedway Motors tube nuts, part number 91031820. Using a brake line tubing bender, Speedway Motors part number 72851503 allowed me to make kink free bends on the new hard lines. I also recommend Speedway part number 72851535 from Titan Professional Tools for flaring 3/16" steel brake line. This compact and easy to use flaring tool is by far the best flaring tool for the best price I have found yet. Simple two-step process gives me a perfect 45 degree flare every time. And compact enough to use right on the car!
With all my hard brake lines ran the way I wanted next up was wiring the valve to the switch and the indicator light that is supplied in the kit. This is a simple wiring set up with just 12-volt power and ground. The switch has a band that can slip over a shifter handle to hold it in place as well.
Just follow the included wiring diagram. You will also want to bleed the front brakes once everything is installed. Activating the line lock is simple. When stopped, apply the brake pedal, push and hold the button. The indicator light will light up showing the valve is working. Release the brake pedal while holding the button and pump the brake pedal again. When you release the brake pedal again the car should not move until you release the button. Depending on the brake pressure, it determines how much holding power this will provide. For my setup using stock GM midsize calipers on the front, it has enough pressure to securely hold my car in place.