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Brake Safety is one thing but what about the feeder lines in Safety!

Everyone tests the brakes puts on new pads or shoes, but what about the brakes lines, but what law enforcement knows you the consumer and driver should equally know for your safety. 

To get you up to speed on the infrastructure (very basically), your brake system is part mechanical–brake pads, rotors and the like–and part hydraulic–master cylinder, brake calipers and wheel cylinders in the case of shoed brakes. The brake fluid that is used to apply hydraulic pressure to the brakes at each wheel is contained within the brake line. The trouble with sudden brake line failure is that there is rarely a warning. If the line is “weeping” an alert operator may become suspicious when brake fluid has to be added or the brake warning light on the dash lights up. At this point, you should have all the lines inspected and check for leaks at each wheel and around the perimeter of the vehicle. Brake fluid is clear and oily but will appear black as it discolors the pavement.

So when you press on the brake pedal pressure builds up in the master cylinder and that pressure is transmitted to the wheels through the brake lines. It is sort of like pressing the trigger on water gun except a brake system is a closed loop system. Leaks are not a good thing.

The brake lines are made of steel and are located under the vehicle which makes them susceptible to corrosion induced by road salt and other contaminants prevalent on the highway. Whether because of the extended length of time vehicles are staying on the road or the chemicals applied to assist winter driving, brake line failures are happening more often.

When replacing your brake lines, the replacement brake hose assembly does not need to look exactly the same as the original brake line, but make sure that the brake lines (especially the new brake hose fittings) will fit the surrounding area where they will be installed. Sometimes the brake hose fitting can interfere with another part of your brakes. Pay attention to any tight spots when removing your brake lines and communicate any restrictions to the vendor who will be fabricating your replacement brake lines.   The NHTSA folks taught us a great lesson in accident investigations worth reading about.  “Older-model vehicles, often driven in harsh conditions, are subject to corrosion over long periods of time, and we need owners to be vigilant about ensuring they, their passengers, and others on the roads are safe.” The problem is worse on vehicles that do not have a high quality anti-corrosion coating on their brake lines.

Loss of pressure in a brake line is a serious problem because it causes your brakes to fail. The brake systems in all vehicles since the late 1960s are split into two separate hydraulic circuits: front brakes and rear brakes, or diagonally with one front and the opposite rear brake sharing the same circuit. If one half of the system loses pressure because of fluid or pressure loss, you should still have two working brakes to help bring your vehicle to a halt. Even so, it can increase the stopping distance dramatically because you only have two brakes that are still functioning.

There’s not much you can do to protect your brake lines from rusting, except maybe to move to a dry climate like Arizona. Undercoating and paint can be applied to the brake lines, but the lines are often hard to reach and it’s difficult to apply an even coating on all sides of the tubing.

As your vehicle ages, you should inspect the brake lines, hoses, calipers and other hydraulic components in the brake system for leaks or excessive corrosion. If the steel brake lines are in poor condition, don’t take a chance. Replace them BEFORE the rust through and start to leak or blow out.

NHTSA’s safety advisory urges owners of trucks, SUVs and passenger cars that are more than seven years old to:

  • Maintain their vehicle and prevent corrosion by washing the undercarriage regularly throughout the winter and giving it a thorough washing in the spring to remove road salt and other de-icing chemicals that can lead to corrosion.
  • Monitor the brake system for signs of corrosion by having regular professional inspections and watching for signs of problems, including loss of brake fluid, unusual leaks and a soft or spongy feel in the brake pedal.
  • Address severe corrosion, marked by flaking or scaling of the metal brake pipes, by having the full assembly replaced.

I can see a few of you saying SOOOOOOOOO WHAT, well, When brake pipe corrosion is in its most advanced state, those rusty lines are prone to break, leading to a potential brake system failure. It’s needless to point this out but having no brakes is… ahem… a potentially dangerous situation for both the driver and passengers. The problem is worse on vehicles that do not have a high quality anti-corrosion coating on their brake lines.

Loss of pressure in a brake line is a serious problem because it causes your brakes to fail. The brake systems in all vehicles since the late 1960s are split into two separate hydraulic circuits: front brakes and rear brakes, or diagonally with one front and the opposite rear brake sharing the same circuit. If one half of the system loses pressure because of fluid or pressure loss, you should still have two working brakes to help bring your vehicle to a halt. Even so, it can increase the stopping distance dramatically because you only have two brakes that are still functioning.

There’s not much you can do to protect your brake lines from rusting, except maybe to move to a dry climate like Arizona. Undercoating and paint can be applied to the brake lines, but the lines are often hard to reach and it’s difficult to apply an even coating on all sides of the tubing.

As your vehicle ages, you should inspect the brake lines, hoses, calipers and other hydraulic components in the brake system for leaks or excessive corrosion. If the steel brake lines are in poor condition, don’t take a chance. Replace them BEFORE the rust through and start to leak or blow out.

Other than regularly taking your means of transport to the service department to check the underbody for rust, what else can you do to prevent such a scenario from happening?

First and foremost, the undercarriage has to be thoroughly washed throughout the winter for an extremely simple reason: removal of the corrosive road salt.

When ordering your brake line, you will need to specify the following:

  • Material of the brake line – rubber or stainless steel braided (colors available on SS braided)
  • Inside diameter of the brake line – 1/8” or 3/8”
  • Overall (end-to-end) length of the hose
  • Thread size of each hose end
  • Fitting type of each hose end and its clocking
  • Any hose brackets and their clocking
  • Any desired accessories such as protective springs, strain relievers, abrasion protective sleeves or heat protection sleeves.

Only the hoses specifically designed for air brake systems are legally allowed to be used on your air brake system if you plan to operate your vehicle on public roads. To gain D.O.T. approval, the hoses have to pass a series of tests prescribed by NHTSA. You can learn more about how the hoses get tested in order to comply at D.O.T.

So how do you know that a hose is legal (and safe) to use as an air brake hose? The only hose assemblies that you can legally use for air brakes are those clearly marked “DOT” on the hose layline as well as on both fittings. Anything else is not approved.

So why should you care? You should care because the air brake hoses are tested to perform in many different conditions which occur on and around your vehicle’s air brake systems – not just pressure. 14 different test areas that D.O.T. air brake hoses must pass in order to gain D.O.T. approval:

  • Construction
  • High temperature resistance
  • Low temperature resistance
  • Oil resistance
  • Ozone resistance
  • Length change
  • Adhesion
  • Internal clearance
  • Flex strength and pressure cycling
  • Corrosion resistance and burst strength
  • Tensile strength
  • Water absorption and tensile strength
  • Zinc chloride resistance
  • End fitting corrosion resistance

It takes a lot of engineering and testing to build an air brake assembly that is D.O.T. compliant, but for you it is easy to tell if you use any particular assembly – look for the D.O.T. designation on both the hose and the fittings.

 

Identifying Brake Hose Fittings

Identifying your brake line fittings consists of three steps:

  1. Identify the thread sizes
  2. Identify the end configurations
  3. Identify the fittings group and type

Brake Line Fittings End Configurations:

On rare occasions we come across a pipe thread, but typically brake hose fittings involve a flare. There are three types of flares on brake hose fittings:

Brake Line Fitting Groups:

  • Banjo
  • Center Support Fitting (bracket)
  • Male Fitting
  • Female Fitting
  • Other/Special Fitting

Banjo Fittings:

  • Round Style – Straight
  • Round Style – Bent
  • Block Style
  • Tube Style – Either Side
  • Tube Style – Left
  • Tube Style – Right

Center Support Fittings

  • Clip mount
  • Bracket Mount

Male Fittings

  • Standard mount
  • Bulkhead mount
  • Clip mount

Female Fittings

  • Clip Mount
  • Bolt-On Mount
  • Bulkhead Mount
  • Bracket Mount

There are many situations which could prevent you from correctly identifying parts of your brake hose assembly.

  • The brake hose fittings may include long tubes with complex bends, making it hard to measure the brake line’s overall length.
  • You may not have the necessary tools to accurately measure thread size and pitch – making it easy to confuse metric and imperial threads.
  • You may not get the clocking just right.
  • You may want to make an adjustment to your existing brake line because your vehicle is being modified (lifts, wider axles, aftermarket brakes…).

Terry Penney

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