My Mechanic Says I need New Rotors With My Brake Job. Am I Being Taken For a Ride?

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No, you are not. Mechanics explain why they change brake rotors along with pads now.

Brake jobs have changed. In the past, there were three major steps for disc brakes. Change the pads and machine the rotors smooth. Add in the proper adjustments and brake line bleeding and you were out the door with a bill and handshake. Over the past decade, there has been a shift away from machining rotors by both dealers and independent shops. Instead, mechanics are simply unbolting the used rotors and tossing them in the recycle bin. Here’s why they have headed in that direction.

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Mark McMullen the owner and mechanic at G&M Services in Millis, Mass. says that it is simply more cost effective to swap the rotors. “We use to machine rotors a while back, but the labor cost and the costs we had to add to pay for the tool and its maintenance equaled the cost of new rotors. So we stopped altogether.” Mark went on to add, “On any brake job in the past we had to inspect the rotors for wear. If they had worn too thin at any point across the friction surface we had to replace them anyway. Do that a few times and it becomes clear that just replacing them as part of the job makes good sense.”

Mark explained why old rotors can’t simply be left on “as is” and then the new pads installed. Mark said, “You could do that, and you might get away with it. However, most times, the brakes will squeal and rotors wear improperly and warp and the customer will come back, so the whole job is wasted and you have to start over.” Mark explained that the pads wear unevenly across the face of the rotor as they age. When the new flat pads go on, they would wear rapidly on the already distorted rotors. The grooves in the rotors cause the squeal. You can see the grooves worn into the rotor above. What is harder to see is that the brake pad (sitting on top) and rotor are not uniformly worn in terms of thickness. The pad was thicker at the top and thinner at the bottom. The rotor had worn a bit unevenly as well.

Tom and Darren Daley of Daley Service in Norfolk, Mass. have been doing brake jobs for decades. Here too the old rotor turning machine is long gone. They explained, “Rotors are inexpensive and they are no longer made of high-quality steel. The new alloy they make them from wears more rapidly. One brake pad life is all they are worth.” Brian Mushnick, the owner of Brian’s Garage in Needham, Mass. added, “New rotors are produced at or barely over minimum thickness, so any wear at all makes the rotors undersized and not eligible for turning.” Lightweighting has its costs.

Shops including a local Lexus dealer pointed to the relatively low cost of new rotors. They are only $45 per side for a rear rotor for a Toyota Highlander, for example. This may be the best evidence that the old way was simply more costly. Each of our trusted shops said that when one factored in the time to inspect and machine a rotor the cost savings were negated and that new rotors always do the job reliably.

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John Goreham

John Goreham