Z51 Rotors, Please help
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
If they're bad enough to need turning, get new ones.
I'd probably replace them anyways, but I've changed just pads on more than I can remember. No issues.
The minimum thickness should be stamped on the rotor somewhere. Make sure they aren't under that first.
I'd probably replace them anyways, but I've changed just pads on more than I can remember. No issues.
The minimum thickness should be stamped on the rotor somewhere. Make sure they aren't under that first.
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Boo. It's usually on there.
Regardless.. found this that claims to be the minimum
Regardless.. found this that claims to be the minimum
Front Brakes: Rotor Discard Thickness 1.19in. or 30.3mm
Rear Brakes: Rotor Discard Thickness 0.965in. or 24.5mm
Rear Brakes: Rotor Discard Thickness 0.965in. or 24.5mm
Melting Slicks
Joined: Sep 2008
Posts: 2,360
Likes: 59
From: San Jose California
DJ
Last edited by djbrun; Oct 22, 2015 at 10:40 PM.
Melting Slicks
Joined: Jul 2010
Posts: 3,001
Likes: 243
From: Surprise, Az
When replacing pads from different manufacturers, I will scuff the rotor surface with aluminum oxide sand paper, then bed the new pads - as long as the rotors are still in the serviceable range. After the bedding procedure, I still see the scuff marks from the sandpaper using street pads, ymmv with track pads.
One thing I like about Carbotech pads is you can swap between pads types without rebedding or being concerned about contamination from different compounds.
If using track pads and driving to/from events, the cold track pads will remove all transfer material -noticeable by different levels of brake squeal.
I've done the sandpaper trick for years, as long as the rotors don't have hard spots they'll be fine.
One thing I like about Carbotech pads is you can swap between pads types without rebedding or being concerned about contamination from different compounds.
If using track pads and driving to/from events, the cold track pads will remove all transfer material -noticeable by different levels of brake squeal.
I've done the sandpaper trick for years, as long as the rotors don't have hard spots they'll be fine.
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,631
The rotors will wear "out edge" surface faster then the inner hub surface.
So turning the rotors, even with a light pass just to square the rotors surfaces to each other to begin with, allows the new pads will mate to the squared surfaces faster that if the rotor surfaces are left catawampus out of square to each other isntead.
Also, when the pads are changed, the E brakes are re-adjusted, and if the rotor drum surfaces have a non outer wear lip, good luck on trying to get the E brakes adjusted correctly. Hence there is not back slot to adjust the E brake star adjuster, so the back rotors have to be pulled to get to the Star adjuster.
So turning the rotors, even with a light pass just to square the rotors surfaces to each other to begin with, allows the new pads will mate to the squared surfaces faster that if the rotor surfaces are left catawampus out of square to each other isntead.
Also, when the pads are changed, the E brakes are re-adjusted, and if the rotor drum surfaces have a non outer wear lip, good luck on trying to get the E brakes adjusted correctly. Hence there is not back slot to adjust the E brake star adjuster, so the back rotors have to be pulled to get to the Star adjuster.
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Team Owner
Joined: Sep 2000
Posts: 25,019
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From: Far NW 'burbs of Chicago
St. Jude Donor '13
Question about rotor Discard Thickness:
Let's say you have a rotor where new thickness is 32.0 mm and the Discard Thickness is 30.3 mm
You're worn out the first set of pads and are going to change them, you get out your trusty micrometer and measure the thinnest part of the rotor as 30.4 mm. That's above minimum by .1 mm
That means that while wearing out the first set of pads, you also wore away 1.6 mm of the rotor.
If you leave the rotor alone and just install new pads, by the time the new pads are worn out then the rotor will be down to about 28.8 mm, well below Discard Thickness.
SO, does the Discard Thickness take into account the additional rotor wear you would get while running through a new set of pads and it's ok to start out just above Discard, or is the Discard Thickness something you should never go below at any time during the pad/rotor life cycle?
In airplane engines; we sometimes had a New thickness, a Minimum Reuse at Overhaul Thickness, and a Minimum Service thickness.
Automobile rotors seem to be different...
Let's say you have a rotor where new thickness is 32.0 mm and the Discard Thickness is 30.3 mm
You're worn out the first set of pads and are going to change them, you get out your trusty micrometer and measure the thinnest part of the rotor as 30.4 mm. That's above minimum by .1 mm
That means that while wearing out the first set of pads, you also wore away 1.6 mm of the rotor.
If you leave the rotor alone and just install new pads, by the time the new pads are worn out then the rotor will be down to about 28.8 mm, well below Discard Thickness.
SO, does the Discard Thickness take into account the additional rotor wear you would get while running through a new set of pads and it's ok to start out just above Discard, or is the Discard Thickness something you should never go below at any time during the pad/rotor life cycle?
In airplane engines; we sometimes had a New thickness, a Minimum Reuse at Overhaul Thickness, and a Minimum Service thickness.
Automobile rotors seem to be different...
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
I HATED my Hawk HPS pads. I threw them away. Combo pads are lousy on the street (noisy and dusty like crazy) and lousy on the track.
It's so simple to swap pads on our cars (one bolt per caliper) that it takes me longer to remove the tires than to swap the pads. I never cut the rotors anymore either.
Can I ask why you chose them? If you haven't bought them I'd suggest you look at other Hawk products, the HT 10's are great for track use and ceramics are great for street use.
Just my humble opinion from experience talking here.
It's so simple to swap pads on our cars (one bolt per caliper) that it takes me longer to remove the tires than to swap the pads. I never cut the rotors anymore either.
Can I ask why you chose them? If you haven't bought them I'd suggest you look at other Hawk products, the HT 10's are great for track use and ceramics are great for street use.
Just my humble opinion from experience talking here.
Burning Brakes
Joined: Mar 2012
Posts: 836
Likes: 43
From: Killeen Texas
Just a thought, if you want to save some money & still get awesome pads; Brake Performance has a Premium Semi-Metallic brake pad that costs much less than comparable Hawk pads. They are very low dust, super quiet & stop the car. (Those are the main desired features right?)
Here is a thread I started on them a while back: (https://www.corvetteforum.com/forums...-are-an-a.html)
(http://brakeperformance.com/brake-pa...brake-pads.php)
Here is a thread I started on them a while back: (https://www.corvetteforum.com/forums...-are-an-a.html)
(http://brakeperformance.com/brake-pa...brake-pads.php)
Retired & lovin' it!
Joined: Mar 2005
Posts: 4,475
Likes: 549
From: Jackson NJ
2007 Z51. Im going from stock brake pads to Hawk HPS pads. Every rotor cutting place I call says "don't turn" the z51 rotors, just put the pads on. The dealerships cant help because with info because they deal in OEM and Hawk is aftermarket they say. I have no noises, shaking, pulsing of any kind right now. Just low pads. Do I find a place to turn the rotors which is going to be hard as hell to do. or just change the pads. And what about the transfer that's already on the rotors. How do I now get the Hawk pads transfer on them with the old transfer still on the rotors?