Benefits of cutting rotors?

VaderSS · May 22, 2006

Brake jobs are one thing I've never paid anyone to do.

On some cars I've owned, the rotors were grooved pretty bad, and in that case, I'd get them turned, but usually I just got new one.

As for turning, just out of hand, I've never done that.

One product I've really been impressed with is CRC's De-Squeak. Since I've been using this product, I've had no brake squeal.

My Miata was squealing when I purchased it, so I pulled the wheels to inspect them and found they had just been replaced. Sprayed the DeSqueak on the rotors and still doing fine.

LarryL · May 22, 2006

Aren't brake rotors lighter because less material makes them cheaper for the manufacturer, and less unsprung weight gives a better ride. If effect, they sell you a rotor that is already as thin as it can be and still work. In that case you can't turn it.

I had a pulsing pedal in a car and changed the pads. But I also cleaned the rotors with carb cleaner, acetone, soap and water and a stiff nylon brush with an overnight soak. Problem gone.

surfstar · May 22, 2006

I bought my car with 80k miles on it. Replaced the front pads (originals maybe) at ~135k with $40 ceramics. I doubt the rotors were replaced by the previous owner and now I have 190k miles on it. I'm easy on the brakes and mostly hwy miles. Rotors have some grooves, but seem to be doing just fine.

I think if you're doing the work yourself and can get rotors for a good price, replace instead of turning. Next time I'd just throw some rotors on with the pad slap and it would still be less than a $100 brake job.

I haven't touched the rear drums either.

ccs2k1 · May 22, 2006

quote:

Originally posted by Gary Allan:
I cannot for the life of my figure out how auto manufacturers devolve reliability and longevity and call it advancement.

"Value" engineering and "cost improvement" engineering: the process of making a good product cheap for the sole purpose of improving the company's bottom line.

Gary Allan · May 22, 2006

quote:

Originally posted by Volvohead:
The ATE systems perform better in my experience. That's the tradeoff with improved braking performance - the tires, pads and rotors eat themselves up faster.

[/QB]

So, you're saying that they are basically in conflict of providing the superior performance for some utlra high speed service ..and sacrifice longevity??

Are stopping distances shortened measurably ..and do these cars go appreciably faster to require it? Does the handling see enough significant improvement with reductions in unsprung weight to warrant mass reductions in the rotating components ..ie reducing the heavy flywheel effect as it degrades accelleration?

Are we that "deep" into the margins of enhancement?

Otherwise you're paying dearly for right to marvel at the technology

Lame brakes are nothing new. I had a 1980 Pukeout 504 wagon. I drove over 300 miles a night ..naturally this was virtually ALL highway. I had a pulsating pedal. I had the oil changed every 3 weeks (3500 OCI - diesel) ..and they changed the pad every time I came in ..and machined or replaced the rotors as needed (1 year unlimited mileage warranty). It never stopped. One session of this was so sever it burned a wheel bearing ..that another dealer fixed. That wheel bearing failed due to the spindle being burned.

I finally bought aftermarket pads ...never had a problem after that.

I don't know what they were thinking when they made this

Volvohead · May 22, 2006

quote:

Originally posted by Gary Allan:
So, you're saying that they are basically in conflict of providing the superior performance for some utlra high speed service ..and sacrifice longevity??

Are stopping distances shortened measurably ..and do these cars go appreciably faster to require it? Does the handling see enough significant improvement with reductions in unsprung weight to warrant mass reductions in the rotating components ..ie reducing the heavy flywheel effect as it degrades accelleration? [/QB]

Correct, right on down the line, but with two caveats.

These higher performance brakes and tires perform better at lower, real world speeds, as well.

And I would be happier with more massive rotors, even at the expense of a little extra unsprung weight.

But this stuff is nothing new. These principles have been in play as long as I've been crawling under cars. Make the materials harder to increase service life, and they're less adept at working the friction.

BlownF150 · May 22, 2006

Did a front brake job on my daily beater today. I just replaced the rotors as it costs just as much to have them turned. I have them turned in the past even if there was no shudder present as I liked the new pads to have a fresh surface to start with. Pads: Duralast Gold = $30. Rotors: Made in China = $28. 2 year warranty on all parts.

ccs2k1 · May 22, 2006

My local NAPA store also has a machine shop. Cost of cutting rotors: $17.

VaderSS · May 23, 2006

As an FYI, I bought the $14 rotors for my Olds Ciera. After 80k, they showed many hairline cracks. As I was giving it to grandma, who drives nowhere near as aggressively as me I put another set on. They still look great 35k later.

Master ACiD · May 23, 2006

as you use the brakes the pads and rotors WEAR down.

whats the difference between making the rotors wear down via the pads, or taking them off and having them turned? answer: there is no difference! well besides the fact that turning the rotors will get rid of a pulsing brake petal.

theres lots of misconceptions here guys. the auto makers spec a minimum thickness on a rotor for a good reason, and its so that the rotor isnt used when its too thin. every rotor out there today has a minimum spec cast into it. how it gets to be thin does not matter, weither its from use, or turning on a lathe, the fact remains that if the rotor is within spec thickness, its a GOOD rotor.

i took my rotors into an auto parts store to get them turned because the petal would lightly pulse when pushed down. the guys speced it and told me it was below minimum thickness and they would not be able to turn it for me. i ended up buying a pair of new rotors.

for the guys that buy new rotors reguardless of how little they are worn let me ask you a question. when youre shampoo bottle is 60% used up, do you throw away the bottle and buy a new one even though theres still 40% shampoo left in the old bottle?

thooks · May 24, 2006

Gary, I take it since you like to replace the pads atleast once a year, you aren't driving a 99-2001 Silverado.

Folks, the real reason why there is so much warpage is because most all of them are now Made in China. Also the reason why they are thinner and won't last through 2-3 "brake jobs" nowadays.

I remember when you could get 2-3 turnings out of a rotor.

Oh, and if you gotta ask "why do you say the reason is 'they are Made in China'", well....ya just don't get it.

G-MAN · May 24, 2006

Actually, I do get it. Most rotors don't warp (even the ones made in China). The vibrations most people feel are caused from uneven pad filming on the rotor surfaces.

Gary Allan · May 24, 2006

You're right, thooks. I don't own a Silverado. Nothing ABS ..nothing exotic either. I don't think I ever will. If I do, I hope that I never have to worry about the ante for ownership. They're really over the top with mandatory expenses here.

I've found nothing wrong with made in China rotors. I did find fault with my OEM's on my Caravan (the van was made/assembled in Canada - I dunno about the rotors). The OEM rotors had air bubbles in the castings. Way too deep to cut out. You would just be driving along happy as heck and then find that you had deep holes in your rotor. Got new rotors from Big A ..at the time they were $50 each ..and they were made in China. As you can figure this was a long time ago.

I don't think that any common rotor is made domestically anymore. Maybe some hi-per or fancy cross drilled/slotted thingy.

Anyway ...I don't have an annual "rule". I get them up on a lift every 6 months ..just to see how much meat is on the pads. The rear drums on the wife's jeep are original @ 107k. The drums are getting a ridge to them, for sure, but the shoes are just fine.

Papa Bear · May 24, 2006

Why can't we build rotors in North America at a reasonable price ??
Pretty soon we will need a 3rd world country to come over and wipe our butts 'cause we're too lazy or dumb to do it ourselves.
It's sad !!
P.B.

ALS · May 25, 2006

I've been driving Volvo's for 25 years. From talking to techs at the dealer, the brake rotor cutting machine is the least used piece equipment in the shop. I remember the guys making fun of a new guy that came from Sears. When the senior tech was showing him around the guy made a point of saying when he saw the brake cutter "I'll be getting a lot of use out of that." The Tech looked at him and said I've been here over twenty years and I haven't used it 5 times.
At the time the dealer was carrying both Volvo's and BMW's.

XS650 · May 25, 2006

quote:

Originally posted by Gary Allan:
I did find fault with my OEM's on my Caravan (the van was made/assembled in Canada - I dunno about the rotors). The OEM rotors had air bubbles in the castings. Way too deep to cut out. You would just be driving along happy as heck and then find that you had deep holes in your rotor.

It's not a bug Gary, it's a feature. Some people pay extra for holes in their rotors.

Blake Sobiloff · May 25, 2006

Yeah, I'm amazed that the barbells I bought last year are made in China. I mean, I can't believe the Chinese can take low-grade iron, mold it, paint it, and ship it across the world for less than we can do so here in the US.

thooks · May 25, 2006

Gary,

Most of the 99-2001 Silverados/GMC Sierras are doing over 100k miles on a set of pads.

I did. And when I sold it at 100k, there was atleast 20k miles left on the pads.

Pads (OEM AC-Delco) for those trucks are $100 per axle. And worth every penny.

labman · May 25, 2006

quote:

Originally posted by Blake Sobiloff:
Yeah, I'm amazed that the barbells I bought last year are made in China. I mean, I can't believe the Chinese can take low-grade iron, mold it, paint it, and ship it across the world for less than we can do so here in the US.

One big factor is environmental regulations. The MSM has missed the story about the massive brown clouds over the Pacific down wind of the Indian and Chinese foundries. It absorbs massive amounts of sunlight that used to reflects off the water. Global warming?

Gilitar · May 25, 2006

quote:

Originally posted by G-Man II:
Actually, I do get it. Most rotors don't warp (even the ones made in China). The vibrations most people feel are caused from uneven pad filming on the rotor surfaces.

How do you get rid of the film???

Benefits of cutting rotors?

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