Line Locks and Centering the Front Brake Line
by Norm Wnuk
Out in the trail we want to think about being unstoppable rather than stopping. As soon as we stop forward progression, chances are we're stuck. Here are two brake modifications that can keep you moving forward or stopped when you want to be. This tech article is intended to give you enough detail to understand what it takes to make the modifications. Your install will vary widely and require more steps than outline here.
A line lock (Fig. 1), also known as a roll stop, is an electronic solenoid which holds your wheels as if the brakes were on even when you don't have your foot on the pedal. Similar to a Trans-Brake, in racing it allows you to get your engine to launch RPMs before the light goes green. On trails rides it is equally useful holding you on steep inclines and precarious situations where you wish you had a third foot, particularly if you drive a stick. (It's also a great way to fake an e-brake during inspection time.)
Fig. 1
You can use line locks for the front or rear brakes, but on the front you need to modify the proportioning valve. The front lines split at the differential switch block going to each front wheel separately, requiring a plug on one of the front lines. This will not affect your braking and will allow you to put in a T-fitting line on the front axle in the center like the rear axle, more on this later.
Items needed for front and rear line lock installation
Installation This installation goes over the way I installed line locks on an 83 CJ. This is by no means the only way and the line locks also come with detailed install instructions. Start by figuring where you want to install the line locks. Note: you always want to install them after the proportioning valve. I installed my below the master cylinder on the fender-well (see Fig. 2). I also chose to relocate the pressure differential switch block and used a 94 Wrangler version. On CJs these are located on the frame near the back of the driver's side front spring hanger. I put where I've seen it on Wranglers, below the master cylinder. The wiring plug for the brake warning light plugs right in. I plugged one front line (see red arrow in fig. 3).
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Next I ran two short lines from the master cylinder to the proportioning valve, one for the front brake line and one for the rear. Then two more short lines from the pressure differential switch to the line locks. The rear line lock connects with a union to the rear brake lines. I put new tube to the front since I was installing a rear line t-fitting in the front. See below for finishing the front brakes.
Centering the front brake line
Ever have your front brake lines stretched a little to taught for comfort? This modification allows you to flex like Arnold in Terminator and not compromise your brake lines. By using the same line as your rear with a t-fitting on the center of your axle your lines run the length of the axle and never bind during extreme droop. This is the rubber hose that goes from the center front of your gas tank (on a CJ) to your rear differential and has a t-fitting going to each tire. I ran a new brake line from the pressure differential switch block to just under the grill body mount. Fig. 4 is a view from where the radiator should be. Simply run new line from the t-fitting to your drums or calipers along the top of the axle. Use rear style clips or wire ties to hold down the new line.
Fig. 4
Now, ground one wire from the line lock and run the other two to a switch on the dash. I run both front and rear off one switch. If you want to do burn-outs you can run the front and rear on separate switches. I also recommend having an indicator light on when the switch is on. I have stalled unnecessarily by forgetting to release the line locks.