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Stop here! Let's talk about brakes

2025 messages,  Last post on May 03, 2013 at 4:53 PM

You are in the Maintenance & Repair Forum.

What is this discussion about? Brakes

Messages Page 198 of 203

#1968 of 2025 Re: Why is is...? [imidazol97] by jipster

Dec 01, 2010 (8:37 pm)

Replying to: imidazol97 (Dec 01, 2010 7:54 pm)
How much were good quality rotors to replace the ones they wanted to turn.
 
From what I recall the rotors were about twice as much as turning them.
 
 I had high quality pads put on both my cars. Napa ceramic on the Regal and the OEM pads on the Mazda.
 
A friend said he thought they had machines now that turned the rotor while it was still on the car. Don't know if that's true, but it doesn't seem it would take that long to turn a rotor. The guy at the dealership made it sound like there was a lot of time and effort involved in it. I have no idea.

#1969 of 2025 Re: Why is is...? [jipster] by obyone

Dec 02, 2010 (12:03 am)

Replying to: jipster (Dec 01, 2010 8:37 pm)
A friend said he thought they had machines now that turned the rotor while it was still on the car.
 
That was designed specifically for FWD vehicles. I remember Snap On wanted $2K for their model. Was suppose to save labor as removing the rotors from a FWD was a little difficult

#1970 of 2025 Re: Why is is...? [jipster] by isellhondas

Dec 02, 2010 (7:33 am)

Replying to: jipster (Dec 01, 2010 8:37 pm)
Oh, there is a HUGE profit in turning rotors!
 
The "on car" machines are a snap to hook up. The guy working on the car hooks up the machine and walks away. While he is waiting for the machine to finish, he can go work on another car.
 
Shops charge 200.00 or more to turn two rotors!
 
But, it's not the money that bothers me as much as the fact it just isn't needed most of the time. It takes a layer of metal off which only creates more heat.

#1971 of 2025 Re: Why is is...? [isellhondas] by shipo

Dec 02, 2010 (7:54 am)

Replying to: isellhondas (Dec 02, 2010 7:33 am)
Creates more heat?
 
Hmmm, silly me, I always thought the reduction of metal simply reduced the thermal mass of the rotor, thus causing it to get hotter per calorie of heat added to it. Shows what I know.

#1972 of 2025 Re: Why is is...? [shipo] by isellhondas

Dec 02, 2010 (8:14 am)

Replying to: shipo (Dec 02, 2010 7:54 am)
I always thought that the thinner the rotor the greater the effect of heat which would lead to fading and warpage of the rotors.
 
At least that's what I meant.

#1973 of 2025 Re: Why is is...? [isellhondas] by shipo

Dec 02, 2010 (9:02 am)

Replying to: isellhondas (Dec 02, 2010 8:14 am)
Yup, the lower the thermal mass, the faster the rotor heats up when any given amount of heat is injected into it. The faster the rotor heats up, the sooner you get into brake fade territory (not to mention "hot spotting" and/or warping the rotor).

#1974 of 2025 Re: Why is is...? [shipo] by isellhondas

Dec 02, 2010 (9:04 am)

Replying to: shipo (Dec 02, 2010 9:02 am)
And the very reason I don't want them resurfaced unless absoulty necessary.
 
The shops will tell you that they can't guarantee their work and some will flatly refuse to not machine them.

#1975 of 2025 Re: Why is is...? [isellhondas] by shipo

Dec 02, 2010 (9:38 am)

Replying to: isellhondas (Dec 02, 2010 9:04 am)
And also why I never machine the rotors on my cars, I always replace them when new pads are required.

#1976 of 2025 Re: Why is is...? [shipo] by isellhondas

Dec 02, 2010 (9:45 am)

Replying to: shipo (Dec 02, 2010 9:38 am)
So, why would you replace a perfectly good, in spec set of rotors?
 
Kinda seems like overkill to me.
 
Do you replace your calipers too?

#1977 of 2025 Re: Why is is...? [isellhondas] by shipo

Dec 02, 2010 (11:12 am)

Replying to: isellhondas (Dec 02, 2010 9:45 am)
"Perfectly good" is a matter of opinion. When I pull the brakes off one of our cars, the swept area of the rotor always exhibits considerable metal loss, too much for my tastes. While said rotors may still be within spec, the loss of thermal mass is due to normal wear is typically much greater than the metal loss from "turning" or "facing" used rotors. Measure them, you might be surprised.
 
As for replacing calipers, no, typically I don't do that. The lone exceptions have been when there was damage to the piston either due to corrosion (from the previous owner not flushing the brake fluid often enough) or (in one case only) damage due to some ham-handed previous owner/maintainer.

Messages Page 198 of 203

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