Brake line repair is a necessary maintenance step in many vehicles as they begin to age. Brake lines are susceptible to becoming brittle, rusting, and leaking, which degrades the reliability of the brake system. Exposure to the elements of nature is the main reason that brake lines degrade. Temperature, both hot and cold, along with moisture can cause a brake line to rust or degrade and leak.
Why Not All the Time?
Compression fittings can splice pieces or sections of steel brake line together to create a seal between the two sections. The pressure running through brake lines is extremely high. Compression fittings typically are not capable of withstanding this high amount of pressure. When the pressure of the brake line exceeds the pressure that the compression fitting can withstand, the fitting will blow and your brakes will not work. Several states have made the use of compression fittings on passenger cars illegal for this very reason. Therefore, when dealing with passenger cars, the recommendation will always be to replace the brake lines instead of repairing them with a compression fitting. If you are working on your brake line for your everyday vehicle, the best thing to do is to replace the line instead of fixing it with compression fittings.
Because of the unreliability of compression fittings on brake lines, the use of compression fittings is not widely recommended. There are certain instances where using a compression fitting is acceptable, however. If you are repairing the brake lines in a vehicle that is not a passenger car used for everyday road travel and transportation, compression fittings are an acceptable brake line repair. It is acceptable to use compression fittings in a vehicle that is not meant for public transportation, such as an off road vehicle used for play, or a farm vehicle or work truck that is not used on public roadways. Any vehicle that does not travel on public roadways and does not travel at high rates of speed can have a brake repair using compression fittings. If the compression fitting were to blow on a vehicle of this sort, the low rate of speed would allow the driver to roll slowly to a stop.
Compression fittings are also admissible to use on brake line repairs when the repair is temporary. Again, it is only acceptable to use compression fittings in a vehicle that is not used for public transportation. For example, if you were rebuilding a car or repairing a car, you might choose to use a compression fitting to repair the brake line. The compression fitting would be a temporary solution that would allow you to complete other repairs or work on the vehicle. When repairing or rebuilding a vehicle you may need to start the vehicle and test the acceleration in a closed setting. The use of compression fittings is alright in this situation as long as the fittings were removed and brake line replaced before the vehicle is used for passenger transportation or on public roads.