Turning brake rotors question

[Bob]

I know the standard professional way to do a brake job is to turn the rotors (drums) to get a good surface and eliminate runout. I can understand this from a pro, because no shortcuts should be taken on a customer’s brake job.

For myself, I usually have more time than money. (Damn family law judge) If there is no damage to a rotor, no runout, and it is above minimum thickness I don’t have the rotors turned. I would rather have the metal on the rotor than on the machine shop floor. I work over the surface with a cup type wire brush and/or sandpaper to give the pads a good start in life.

Agree/disagree?

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[Erin]

Sounds alright.

I may be wrong but I would assume if the rotors are so messed up that they NEED turned, they are probably beyond repair anyways. Who wants to deal with removing messed up rotors, take them in, pay money to have them turned, etc. Just spend a few more bucks and get brand spankin new if the rotors are not in good shape.

A shop cannot take any type of shortcut that most home mechanics do. When a shop takes shortcuts, they are taking a risk of the car coming back. They have to do it by the book.

[Cameron]

[quote=”DBFSubs21!” post=114977]I know the standard professional way to do a brake job is to turn the rotors (drums) to get a good surface and eliminate runout. I can understand this from a pro, because no shortcuts should be taken on a customer’s brake job.

For myself, I usually have more time than money. (Damn family law judge) If there is no damage to a rotor, no runout, and it is above minimum thickness I don’t have the rotors turned. I would rather have the metal on the rotor than on the machine shop floor. I work over the surface with a cup type wire brush and/or sandpaper to give the pads a good start in life.

Agree/disagree?[/quote]

I disagree but I guess you have to do what you can afford up to a point. But look at how you prioritize your expenditures. If people cannot afford to maintain their brakes properly then they should not be running the car.

If you have worn out one pair (maybe even 2 pairs) of pads on the rotors then you will of course have rotor wear as well.

The problem is that there will be run out on the worn rotor surface (even when installed perfectly square on the hub) because it is most unlikely that the wear on the rotor will be even. If you do not either replace the rotors or machine them perfectly flat you will not have a sound match between the new pad surface and rotor surface and you may well get vibrations-when braking- (due to the DTV condition) depending on the extent of any uneven wear on the old rotor.

Running wet and dry sandpaper over the surface of the rotor is fine for cleaning them up but obviously that will not remove the uneven surface wear (or remove the grooved indentations in the rotor’s metal surface that occur over time).

In my case I do not machine rotors because for my cars the cost of replacing the rotors versus machining the used ones is really not that much so I just replace the “old” rotors with new items of sound quality when each set of pads wear out. If I was running something like a Porsche 997 rotor or some optional pricey high end product I would machine them to within the safe boundaries of minimum thickness as the replacement cost of new items is quite high. I would never run a new pad on a worn rotor on any vehicle without machining the old rotors.

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