Seeing that this month’s emphasis is on brakes, I think that equal time should be spent on routing of the fluid that enables us to stop our vehicles.
Brakes have been around since the days of the chariots, the original chariot parking brake was a stout wooden stick that was inserted through the spokes of the wheels. While this brake could not be applies while the chariot was on the move, it was good enough to stop the horses from wandering around the town dragging the chariot around the town while the gladiators were socializing.
Archaeologists say that the later chariots were equipped with a chain brake. That consisted of a piece of wood that would pivot up against the front of the rear wheels when the drive pulled up on a length of chain. This gave the drive some form of control over the amount of braking he needed at any given time. By the 1800’s lever operated wooden brake shoes were in widespread use. These shoes were usually acted directly to the iron clad rim of the wheels.
In the 17th century French philosopher and scientist Blaise Pascal discovered that by trying to compress an incompressible fluid the force applied was amplified at the working end of a press. Enter the birth of hydraulics.
Have you ever wondered how the smallest person can stop an eighteen wheel tractor trailer with just the tip of their toe? That my friend is the beauty of hydraulic force!
In other articles that I have written, the need of maintenance of this fluid has been thoroughly discussed. It is known that brake fluid is hydroscopic, that is to absorb moisture, because conventional oils and waters do not mix. This makes brake fluid susceptible to both boiling and allowing the metal parts of the brake system to rust from the inside out.
It is said that the strongest chain is only as strong as its weakest link, and in the life of an automobile that lives in the “Salt Belt” that is usually 8 to 12 years after the vehicle was built. The first symptoms are a small loss of brake fluid in the master cylinder reservoir. This is usually ignored by most people for some unknown reason that I cannot fully understand.
Loss of brake fluid means one of two things; the friction material on the brakes is wearing and the fluid is taking up the difference or there is a leak someplace. If in fact there is the beginnings of a fluid leak the second symptom to appear is either a softer or “mushy” pedal, only to be followed by a direct loss of half of the braking system when the brake line or hose finally ruptures.
Brake lines or hoses are the conduits which house and direct the fluid from the master cylinder to their application components, either the wheel cylinders or brake calipers. Brake lines are steel tubing, whose walls are between .019” and .023” thick. Their overall physical diameter are either 3/16” or 1/4” with the newer models have a 10mm diameter. These tubes are usually mounted along chassis rails where they are secured by clips.
Because they have to go around various other components such as rear axles or fuel tanks they are rarely straight. Anywhere under the vehicle where there are pivot points or movement such as the front wheels which obviously turn or in the rear axle which moves in conjunction with the suspension system the steel tubing is changed to rubber flex hoses to facilitate these movements.
All of these tubes and hoses are in constant contact with the environment which include but is not limited to water, snow , ice, salt and all sorts of road debris. The treatment that these parts have on them from the factory can only last so long when exposed to the elements. The very first place of wear and tear usually appears in the clamps or clips that hold these tubes in place. There are rub marks that are usually simple to repair by splicing in a new piece of tubing using special tools to fabricate double flare ends and connected with unions that can withstand the pressures associated with the braking process without leaking or losing any pressure.
Tubing that has been compromised by salt damage tends to be a little more difficult. First is the problem of finding a place to splice in the repair where the integrity of the original tubing has not been compromised. Many times this forces us to replace the entire length of tubing from its inception to its ending point. Ideally pre-bent tubing can be used but many times they are not readily available or just not cost effective. If rolled tubing is available a single length without any splices can be used otherwise precut lengths of tubing must be combined to repair these vehicles.
Likewise the rubber flex hoses need to be monitored for stress or heat cracks or for cuts from hitting debris on the roadway. Flex hose failures are usually catastrophic in nature resulting in an immediate loss of pedal.
This is just a small part of what an accurate inspection should consist of, because if these items do break you will lose your brakes.
236 S. Tamiami Tr.
Punta Gorda, Fl. 33950
Auto Repair, A/C Repair, Oil Change, Brake Repair & Transmission Services