[HWYSTR455]

When replacing brake pads, it has always been SOP to turn rotors/drums for me. Lately, I've heard people changing pads without turning more and more often, and am wondering what people here are doing. A friend owns a circuit race chassis prep shop, and says he doesn't unless the rotor is damaged or excessively worn.

Do you turn your rotors when changing pads or not?

If usually not, when DO you decide to turn rotors?

Does pad bedding take longer on an un-turned rotor?

Doesn't a pedal pulse on un-turned rotors?


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[Z Code 400]

Mike,

I no longer turn them unless they are grooved (badly) or out of round.

[sstripes96]

Ive never turned them unless I can feel a warped rotor in the pedal or they are scored.

[wheelspin]

Another vote for not turning rotors unless they are heavily scored or warped. I recommend scuffing the pad contact area of the rotors w/ coarse sandpaper or the flat bottle brush style hones made for this purpose. The rotor scuffing provides the "bite" that profiles the new pads, and you will not experience pedal pulsing when braking unless you had it before changing pads.

Les

[stevep]

If you know that you do not have a pulsation @ 65-70 MPH when you apply the brake, do not turn them.

I would rather replace the rotor than turn it.

[HWYSTR455]

Warped, that makes sense, scored too. Are we talking about visible surface variances, or only if you feel it in the pedal?

I have the C5/6 setup on the daily driver, and the pads are almost gone. I can see the surface isn't completely smooth or flat, and wonder if this would make for a turning candidate? Don't feel anything in the pedal though, but the surface certainly isn't flat.

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[Z Code 400]

Run it...

When I worked for BMW and MBZ, they had very explicit instructions not to turn rotors, even with the presence of grooves, so long as the pedal disn't pulsate. Their reasoning was by machining the rotor, you weaken it...Robert

[HWYSTR455]

Hm, may just do that then, toss the new pads on and see how it goes. The C5/C6 rotors are pretty thick, 1.25 if memory serves me correctly, and believe that a 'clean-up turn' would prevent them from being weakened. There is a minimal rotor thickness spec for all rotors, and as long as that is maintained, would think that turning would be safe. Any thoughts or comments on that logic?

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[performerrpm]

its only what 7 bucks to turn a rotor? its been awhile since had it done. i usually check my pads and if its close to time i replace them and used a scuff wheel on a die grinder just to clean the glaze on the rotors. if they pulsate or have grooves worn in id turn them if i had time but usually it works out that i dont have time and just buy new if there cheap enough, acorse if the rotor price goes much over 30 bucks then i turn them like it or not if their usable. you should be fine staying in that minimal thickness if you do turn'em

[Bill Eveland]

There are really 2 thickness specs to look at. Minimum machining and minumum thickness (discard) the differance can range from .015 to .070? or more depending on application. I rarely install pads without machining rotors. Alot it's the other way around, the rotors are warped so bad and the pads are 50%, but i'll sell new pads with new rotors so everything is new and seats together better.

I use an on car lathe at work and a regular pass will take .012" off. It's usually a 1 pass deal unless the rotor is real bad. it will cut a rotor too withon .003 runout. The bench lathes are not as an accurate deal and might need more to cut off because usually most don't have a 1 pass cut availability, and a fast and slow pass are needed on those.

[HWYSTR455]

Out of curiosity, what would the Minimum Machining and Minimum Thickness specs be for an '04 Z51 'vette?

There's a machine shop up the street that can turn my rotors, think they charge $15 a piece. That's on a typical stand lathe.


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[performerrpm]

the parts store can tell you the specs, or at least oreily's can.

[Region Warrior]

GM has said for years not to unless it's warped.
Believe the better aftermaket's advise against it also.
Our tech's do anyhow. Probly cause it pays more.
They also run a scotch roloc disc around it regardless.

[HWYSTR455]

I just spoke to Noel at Touring Classics, where I purchased the C5/6 brake kit from, and he suggested having them turned and see if they fall within specs. If not, obviouosly, replace them. Now it's just a matter of finding a decent place to have them turned!

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[mikeb]

Like everyone else said, I only turn the rotors when pedal pulsation can be felt, or there is visable damage on the rotor. I only turn once, then discard the rotor.

[HWYSTR455]

Aw the heck with it, I just went ahead and bought new rotors. I got brand new drilled, slotted, and zinc washed rotors, front and rear, for a total of $140 bucks.

http://cgi.ebay.com/ebaymotors/ws/eB...m=190296759743

I'll take the old ones up and have them turned and see how they work out. At least this way when I go to do the brakes I won't get zapped by not having rotors that turn out. I can save them for next time, have a rotation, no pun intended!


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[sstripes96]

On all the Chevys Ive driven there is a mark that is cast into the rotor across the width of the rotor. You will be able to see it if you sit at the front of the car and look aft. Turn the rotor until the mark comes up. This mark is the minimum machineable width.