Tech Tip: Machining New Rotors Is Unnecessary

Tech Tip: Machining New Rotors Is Unnecessary

New quality rotors should simply be thoroughly washed and installed.

It isn’t uncommon for techs to ask if new rotors should be machined. The answer, according to Bendix Answerman Chuck Kennedy, is a resounding no: machining new rotors is an unnecessary step that could actually lead to more problems that might not have occurred otherwise.

“New rotors are machined on accurate and costly computer numerical controlled (CNC) machines,” said Kennedy. “The use of a CNC machine minimizes run-out and stack-up tolerances from multiple operations such as those that would be needed on a bench lathe. It is highly unlikely that the average shop has this type of CNC equipment at their disposal.”

According to Kennedy, new rotors should merely be washed thoroughly with soap, water and a stiff brush and then installed. He also recommends checking old rotors to determine the source of run-out — a step that is often overlooked. Checking hub assemblies and axle flanges for run-out may help determine what will happen after a new rotor is installed on the vehicle.

“New rotors cannot fix a run-out issue, but if a thousandth or two of run-out on a rotor is clocked to offset a small amount of run-out in a hub, this can help give the rotor extended life and do a lot to keep pulsation issues from arising after a short time,” said Kennedy. “Using quality brake components means you won’t have to worry about the fit or finish, and you can be sure your concerns are handled should any issue ever arise.”

For more information about the Bendix line of rotors, or tech tips from the Bendix brand, log on to



You May Also Like

Tesla Wheel Bearing Replacement

The process of replacing the hub unit on a Tesla is the same as many cars and light trucks.

The most common EVs on the road come from Tesla. The Model S, 3, X and Y share similar drivetrains and wheel-end components like the wheel-bearing hub units.

The process of replacing the hub unit on a Tesla is the same as many cars and light trucks. You do not need insulated tools or gloves to replace chassis parts. The only complications come with initial diagnostics and setting modes for service procedures.

Brake Pad Edge Codes – What Can They Tell You?

The edge code is a language written by engineers, federal entities and industry associations.

Brake Problems

Reducing brake drag on late-model vehicles is not accomplished by a single component; it takes a system.

The Real Cost of Installing Cheap Brake Pads

The brake repair market is starting to become dominated by a “good enough” mentality.

Brake Boosters and Start/Stop Vehicles

For a vacuum brake booster to work, it needs a source of vacuum.

Other Posts

Wheel Speed Sensor and Hub Unit Diagnostics

All wheel speed sensor codes are just the starting points of a diagnosis and not a reason to order a part.

Better Brake Law Update

Learn the latest about the salmon-inspired law.

Identifying Brake Issues With Brake Dust

Brake dust can indicate what could be wrong. This video is sponsored by Auto Value and Bumper to Bumper.

Top 10 Brake Mistakes

Here are the top 10 brake mistakes technicians can make.