As winter approaches and brake repair jobs begin rolling in to the shop, the engineers at Ingersoll Rand want to share some important tips for ensuring a safe and reliable brake repair or replacement for your customers.
Whether it’s a DIYer replacing brake pads at home or a technician in a shop, the primary concern in a brake job is cleanliness. This is one area that is often over-looked both at home and in the shop. Today’s slip-on rotors fit between the wheel and the brake hub. Since rotors are made of steel, they’re subject to corrosion and rust. In order to avoid making the situation worse, make sure the wheel hub and rotor are spotless.
“Consider oil spreading over the top of a lake,” said Jim Cookingham, owner of Nex Tech Automotive Engineering in Somerville, NJ. “Just five quarts of oil can cover 10-12 acres of a lake. Similarly, oil spreads on a rotor when it gets hot. One dirty thumbprint can significantly decrease brake efficiency.”
A brake only needs to be out of alignment by about 0.002 of an inch in order for the driver to feel the shimmy in the wheel or the pulse in a brake pedal at high speeds. Even worse, corrosion, dirt or oil in the mounting can create a dangerous situation if the brakes are not performing well or are out of alignment.
Another tip for brake repair and replacements is to do a thorough inspection of the rotor. As brake pads wear and tear, so do rotors. Because the brake pad is flush against the rotor, they typically wear in the same patterns. Upon close inspection of a rotor, you’ll notice the wear looks like a mountain range. Placing a smooth brake pad on that rough surface will decrease the performance of the brake pad. The pad rests on the peaks of that rough surface, significantly increasing the pounds of pressure per square inch. The result? Heat and warping of the rotor can lead to squeaky brakes, or brakes that don’t perform as well.
There are a few options to ensure that the brake pad and rotor sit flush against each other. The first would be to replace the rotor, matching a new rotor to the specifications of the manufacturer of the vehicle and brake pad. Another option is machining the rotor surface to the correct manufacturer specifications.
“You can make the rotor too slick – you don’t want it to be shiny like chrome,” said Cookingham. “If you make the rotor too smooth, you reduce the coefficient of friction enough that the driver has to increase pressure on the brake.”
Each individual situation should be assessed appropriately. A general rule of thumb is to always inspect the rotor and install the brake pad so that it’s flush against the rotor. Whether this is achieved through machining the rotor or replacing it depends on the technician’s abilities. Above all, make sure that all parts, tools, and hands on the job are as clean as possible. The brakes are arguably one of the most important parts on a car in terms of driver safety, so doing the job right every time is of utmost importance.