Brake repairs can be costly, but because the brakes are easily the most important safety feature on a vehicle after putting a competent driver behind the wheel, most everybody can agree that they are necessary costs and usually do their best to maintain them. But some people are still put off by the prices of some of the more high-dollar wear items, like brake rotors. I’ve seen rotors so thin that they should have cracked with a little bit of pressure and so warped that I had to wonder how long the skid marks were from the panic stop. But I’ve never, ever seen what counter guy Peter has seen:
*female customer walks in carrying an extremely discolored and scored brake rotor*
Customer: Umm…I need one of these things.
Me: *staring in bewilderment* Yeah…I’d say you do.
Customer: It’s for a ’99 Dodge Dakota. 2WD 3.9 V6.
Me: Okay…hang on…can I asked what *that* is (pointing at a ~3 sq. in. part of the rotor that looks like it was attacked by a bear) or what caused it?
Customer: Well that’s actually my question. See, my friend told me that since it’s warped I could just have it sanded down. So she started trying to sand it with some steel wool before we decided to bring it up here.
Me: …the short answer is no…no you cannot SAND a brake rotor…
Customer: Oh…well okay then yeah I definitely need one.
Excellent effort, but poor result. If you are skillful enough, you might get away with a very light scruffing of the rotor surface with sandpaper if you do it right, but the image in my head looks like the customer sat on the same section of the rotor, sanding from the edge to the hub for about an hour, then moving on to the next section. Remember, there are professionals out there willing to help. Cutting rotors isn’t expensive, and honestly, they get me off of the counter and back to the meditation zone that is the brake lathe. But for now, let me tell you about our rotors…
Rotor warping? Eh, that’ll buff out.
If a rotor warped once, it will most likely warp again. On my vehicles, if my brakes are pulsing, I just install new rotors (or drums) – they aren’t that expensive on most vehicles.
I just did this on my 84 C10. The brakes were pulsing after getting warmed up to operating temperature.
The brakes would pulse, but I couldn’t feel it in the steering. Hmmm. I did the “drag the parking brake” check, and felt no pulsing coming from the rear drums. I took off the front wheels and looked for telltale discoloration marks on the rotors and saw none. I spun the rotors by hand to feel for spots where they may be dragging the pads… nothing I could feel. But they did have a slight lip and the pads were almost down to the squealers, so I put new pads and rotors on.
Brake pulse is gone.
Oh, and I’ve seen some “mechanics” use roloc or bristle-locs to take the glaze off rotors when doing a brake job. I imagine scuffing them with sandpaper or scotch-brite would also work okay for the DIY person if there was no brake pulse and the rotors weren’t passed their minimum thickness or showing signs of uneven wear… but as the author said; machining them isn’t very expensive and changing them out for new ones isn’t much more.
Brakes are important.
And now a view from the other side of the counter: I have had a yahoo at the parts store ruin a good set of brake drums turning them. And did so out of complete ignorance. I don’t know how an hour training really prepares you to turn drums and rotors. But for some reason, auto parts stores think it does. I took a pair of drums that had some slight wear to Azone many years ago to get them turned due to some slight wear caused by one rivet getting into the drum. The drum was not worn bad but I decided to get a clean surface for the new shoes. I gave them to the genius working there who took them back, mounted them on his brake lathe, and after two gouging cuts, pronounced them out of tolerance. The guy did not know what he was doing. I have turned them on a lathe before and been able to salvage a set with “hard spots” in them. This guy did not even try. Gee- thanks dude.
How long do you have to work at it with STEEL WOOL to do serious damage to a brake rotor? I could see damaging a rotor with a power sander or 80 grit sandpaper and some determination, but using steel wool to trash your rotor takes a special kind of crazy!
I also wonder how steel wool can damage a rotor? Only thing it could do is scuff them.
Counter guy measured a pair of drums for me ,said they would not turn them because they are out of limits now 10.17 now with 10.37 the limit. OK he showed me ,I said you are reading the MM scale for the limit.
I learned years ago that bringing a car to Joe Blow Tire Center can cause warped rotors. How you say? Since they should be tightened with a torque wtench to spec, they just hammer them on with a impact wrench usually at 150 lbs and be done with it. I would go home loosen them and torque correctly. No more warped rotors.
Took a pair of rotors to a local chain parts store. I had already mic’ed them and knew they were turnable, and told the counter person what they measured and what the minimum was. He says he has to check them himself, because thats their policy – which is fine since I knew they were good. He gets the digital mic out, measures the rotor, then turns the mic ON. He then clears the reading, turns the mic OFF, remeasures the rotor, turns the mic back on, changes the reading from mm to in, closes the mic, repoens the it, clears it again, and tells me “yep they are ok to be turned.”
I leave them with him and walk back in the door a half hour later and can hear a rotor just singing its ass off in the back. I prayed it wasn’t mine, but it was. I raised hell. They bought me one new rotor and sold me the other at cost. I havent been back,
I was the Manager of an auto parts store when a guy came in and said his brakes were acting funny. I had the shop foreman pull it in and take a look. The foreman calls me into the back. I showed up at the door and the car was on a lift with this sun burst pattern where the front wheel should have been. The foreman was laughing his hindparts off saying that the sunburst was the rotor cooling vanes and the brake pad was actually the piston from the disc brakes!
I totalled up the damage for the guy, over 600 bucks, and he said “just put it back together, I cannot afford that.” That is when I had to break the bad news that because we looked at the car and found the unsafe condition, we were liable for any accident that happened as a result of his “brakes”. Pissed off would be an understatement!
Came in the next morning and the car was gone. Must of had a spare set of keys!!