Brake cleaner is a chemical product specifically formulated to do a specific job. There are other chemicals that can be used for cleaning, but many leave behind a residue that can contaminate linings and attack rubber components.
Brake cleaners contain a variety of ingredients. Many have been reformulated to make them more environmentally friendly.
For years, 1-1-1 trichloroethane was the primary ingredient in most aerosol brake cleaners. It works great, dries almost instantly, leaves no residue and is nonflammable.
It was also a relatively inexpensive chemical until a new federal excise tax increased its cost. The tax was applied because 1-1-1 trichloroethane is an ozone-depleting chemical (like CFCs).
To minimize the impact of the new tax, some cleaners now use a mixture of 1-1-1 trichloroethane with other chemicals such as perchloroethylene. Others have eliminated 1-1-1 trichloroethane altogether and use other chemicals. Perchloroethylene is a chemical used by dry cleaners because of its excellent cleaning properties. It dries fast (though not quite as fast as 1- 1-1 trichloroethane), leaves no residue, and is nonflammable. It also costs less than 1-1-1 trichloroethane.
Perchloroethylene is a Volatile Organic Compound (VOC), which is being regulated because it contributes to air pollution. It is also toxic and not biodegradable.
Some cleaners use nonchlorinated formulas, including n-methyl pyrollidone, oxodecyl acetate (acetone), methanol alcohol, toluene, and various petroleum distillates. None of these chemicals are CFCs and are exempt from federal CFC taxes.
Most nonchlorinated brake cleaners don’t clean as well as 1-1-1 trichloroethane or perchloroethylene, nor do they dry as fast. Products without petroleum distillates do not leave a residue.
Nonchlorinated brake cleaners are flammable, making them subject to a national fire code regulation limiting the number of cans of flammable product a retail store or parts jobber can stock. Nonchlorinated brake cleaners are also VOCs and not biodegradeable. Some are toxic. Another alternative are water-based brake cleaners. These typically contain a citrus-based solvent, such as D-Limonene, and other ingredients, such as Methyl Ethyl Ketone. The primary advantages with a water-based formula are nonflammability, no residue, biodegradability of the base product, low VOCs, no ozone depletion or greenhouse gases, and low toxicity. Water-based products clean more slowly and may require scrubbing or wiping to do a thorough job. Drying times are also slow, measured in hours rather than minutes or seconds.