Building a street rod is a rewarding experience, particularly when you get to drive the end result, but there are also some sobering realities involved in assembling an automobile from the ground up. First off, despite what you may see on TV, it takes more than a couple of weeks for the average person to do it. Secondly, you and your loved ones will be riding in it, so the importance of building a safe car above all else can't be overstated. One of the tasks involved in street rod construction that is both time-consuming and critical to functionality is plumbing. Last month we looked at the variety of fittings commonly used, so this time around we're going to give you a few tips and tricks on how to hook them together.
Brake Lines
First let's deal with a common misconception-the relationship between brake line size and hydraulic pressure. Simply put, there is no relationship. The master cylinder establishes the pressure in a brake system; all the lines do is deliver the pressurized fluid.
Brake lines are most often 3/16- or 1/4-inch-diameter and, while there will be no pressure difference between the two, there will be a difference in the amount of fluid delivered. The bigger tubing will carry more volume, so 1/4-inch line may be preferable in some instances (four-wheel disc brakes being an example).
Regardless of the size, when it comes to selecting the type of rigid brake lines to use, there are only two choices: steel or stainless steel. Copper or aluminum should never be used. And Gary Clausen of Pure Choice Motorsports points out that excessively long lengths of flex line, including the braided variety, should not be used, as a spongy pedal will result.
One of the most common mistakes made when plumbing a chassis has to do with routing; brake and fuel lines should be a minimum of 3 inches away from any significant heat sources, most notably the exhaust system. And while it's a little off the subject of plumbing, we have to mention the problems associated with positioning the exhaust pipe too close to an underfloor master cylinder. It is very common for these components to be quite close, but be aware that a master cylinder, and the fluid it contains, will readily absorb heat. We've seen instances where the proximity of the master cylinder to the exhaust was such that the fluid would get hot enough to expand and make the brakes drag, or in the worst-case scenario, not release after being applied. If you opt for an underfloor master cylinder and the exhaust pipe is anywhere in the area, consider fabricating some sort of heat shield.