As we mentioned on the last page, there can be some toxic chemicals in brake cleaner which means that you not only have to make sure you're in a well-ventilated area with the proper protective wear on, but you also need ensure that the car is protected as well.
Those chemicals can harm your car's paint, the final coat finish or any plastics on the vehicle [source: 3M]. It may be a good idea to cover areas of the car that could be exposed to the brake cleaner before you apply it. If using the cleaner outside, make sure that you apply it on a day where the wind won't cause the cleaner to spray on any other part of the car besides the brakes.
In addition to covering up areas of the car, another precaution that should also be taken is to ensure that the brakes and all the surrounding parts are completely cooled down before applying any brake cleaner. Brake cleaner should never be applied to any hot metal on the vehicle because the chemicals in the cleaner have the potential to spontaneously combust [source: 3M]. This combustion can release toxic chemicals into the air that are even more poisonous than they would have been just coming out of the can.
Other than these preparations, there aren't many steps to be taken before applying the cleaner because many brake cleaners don't require that the brake parts be dissembled before application [source: 3M]. The cleaner can be used on brake linings, brake shoes, drums, rotors, caliper units, pads and other areas of the braking mechanism while they're still intact [source: 3M].
Go on to the next page to find out how to apply brake cleaner to your vehicle.