We find it surprising that some mechanics use hydraulic hose for air brake applications. Perhaps they figure that since hydraulic hose is rated at a much higher pressure than air brake hose it is safe to use. The truth is that a hose assembly must meet much more requirements than adequate working pressure in order to assure safety.
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. website: http://www.fmcsa.dot.gov/rules-regulations/administration/fmcsr/fmcsrruletext.aspx?chunkKey=090163348008f293#top.
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. Below is the list of the 14 different test areas that D.O.T. air brake hoses must pass in order to gain D.O.T. approval:
- High temperature resistance
- Low temperature resistance
- Oil resistance
- Ozone resistance
- Length change
- 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.
Choose from the following Parker D.O.T. approved air brake hoses:
- Parker 201 - Fiber braid cover, synthetic rubber inner tube air brake hose
- Parker 206 - Blue fiber braid cover, PKR inner tube air brake hose
- Parker 213 - Fiber braid cover, PKR inner tube air brake hose
- Parker 266 - Fiber braid cover, PKR inner tube air brake hose
- Parker 271 - Synthetic rubber air brake hose
- Parker 293 - Abrasion resistant nylon braid cover, PKR inner tube air brake hose
Posted by Steve Winterowd