Thursday, June 12, 2014

Improve your brake feel with Schnell Autosports' braided brake lines!

A popular and easy way to improve your brake feel is to replace your stock brake lines with braided brake lines.

The braking system on your car is a closed system. A simplified version of how it works, is that when you press the brake pedal, your brake fluid (which is non-compressible) is displaced, and the force of the fluid being displaced into the calipers is what makes the brake calipers close around the brake discs.

With the stock brake lines, the rubber hoses actually bulge slightly from the pressure of the fluid displacement, which translates into less pressure being applied to your calipers, which then makes you have to press harder on the brake pedal to compensate for the reduced braking force (i.e. brake feel). Braided brake lines prevent the hoses from bulging under load, which improves the brake feel.

Stock brake line (top) vs braided brake line (bottom)

Installing Schnell Autosports’ braided brake lines is a simple process, you just have to make sure to be careful and use the correct tools.

Tools needed:
  • 15mm open end wrench
  • 10mm box end wrench
  • 8mm box end wrench
  • Container for catching drips
  • Rags


The fittings on the ends of your hard brake lines are small, and the nuts that you must loosen and tighten can be easily rounded off if you use a regular open end wrench. A properly sized flare nut wrench will minimize the potential of damage by giving you the most amount of surface area possible for turning a nut that would otherwise be impossible to get a box end wrench around. If the fittings on the hard brake line are damaged, you will not be able to properly tighten the lines, and will need to completely replace the hard line.
15mm open end wrench for soft line, 10mm flare nut wrench for hard line
Note how the flare nut wrench makes contact with all six sides to prevent rounding off of the nut.

As you will have to bleed your brakes (to evacuate the air introduced from installing the new lines), it’s easiest to install your brake lines in the order that you would normally bleed your brakes (i.e. starting from the caliper furthest away from the master cylinder, and working your way to the caliper closest).
You will be starting with the right rear caliper (i.e. the rear passenger side caliper for LHD models), so safely raise the rear of the car and remove the right rear wheel.

Take note of where the “soft” brake line meets with the “hard” brake line. When the brake line is disconnected, you will have some brake fluid that will inevitably drip out. Brake fluid is corrosive to your paint, so it is important to try and minimize any spills by having rags and a container handy to catch any. And on the off chance that you do get brake fluid on any painted surfaces, make sure to get it off immediately by blotting (not wiping, which will spread it) with a rag.

Start by disconnecting the end of the soft brake line that goes to the brake caliper. On the end of the soft brake line, there are two flat sides on the fitting designed to allow your 15mm open end wrench to grasp the line. The fittings on the soft line are not designed to rotate, so the 15mm wrench is only used to keep the line in one position while you loosen the fitting on the hard line with your flare nut wrench.

If you are having difficulty turning the fitting on the hard line, do not force it. Use some penetrating spray, give it a little time to soak in, and try again. It is very important that only the fitting rotates, and not the hard line itself. It would also be a good idea to put a rag underneath the fitting to catch any drips once the nut is loose. Once the brake line is free, let the free end hang in a container to catch the brake fluid that comes out.

Make sure the threads on the hard line fitting as well as any surfaces that the new brake line will come in contact with are clean. Attach the new brake line in the opposite manner of how you removed the old one; using the flare nut wrench to only rotate the fitting until tightened snugly. Be sure not to over tighten, as you will damage the hard line.

Now move on to the other end of the old brake line and do as before: use the 15mm wrench to steady the soft line while the flare nut wrench loosens the fitting. There should be less brake fluid that may come out (because of the orientation), but be cautious anyways, as you are closer to more painted surfaces.
With the brake line completely removed, you can now attach the remaining end of the new brake line, and as before, installation is opposite of removal.

Once both ends are installed and secure, you will need to bleed your brakes to remove the trapped air.

There are two bleed nipples per brake caliper, on either side of the rotor. You must bleed both sides to remove all the trapped air. While you are bleeding your brakes using whatever method you choose, make sure to check your brake lines for any drips or wetness that would indicate that the hard and soft brake lines have not seated properly.
Make sure to bleed your calipers from both bleed nipples, otherwise, air will still be trapped.

Once you've bled the brakes, and you’re certain that the new brake hose is installed properly, you’re ready to move on to the next brake line. Installation for all 4 brake lines is similar, and remember to go in order from furthest to closest lines (i.e. rear right, rear left, front right, front left) to the master cylinder.

With all 4 wheels back on, test how the brake pedal feels before driving. If there is any "sponginess", or excess pedal travel, you will have to check to make sure that the lines are on securely, and that all air has been completely bled from your brake system.

Please note: brake lines are manufactured to DOT compliant specifications, and are designated as "for off-road use only"

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