Cracks in Rotor Normal?
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Originally Posted by nastymant
Is this normal? All these cracks in the rotor? I bought this 98 with 75K miles on it. The car shudders bad when i brake hard at 120 mph.
If you car shutters with hard stops a few things to look at:
1) it may be the activation of ABS, which is normal
2) brake pads are tappered
3) caliper mounting brakets are bent
4) Brake fluid may be old
5) old brake pads or glazed over ( melted) brake pads
6) combination of the above
Melting Slicks
Joined: May 2000
Posts: 2,498
Likes: 4
From: Brentwood TN
Originally Posted by patton
they aint norm on my watch
Cracks = excessive heat. Shuddering = warped rotor.
It's time to mosey on over to O'Reilly or somewhere and pick up a couple of new ones. The swap out is something an average mechanically inclined person should be able to do with few hours and a six pack, or a couple of hours and no six pack.
Charlie
Team Owner
Joined: Jul 2004
Posts: 24,652
Likes: 298
From: NJ
St. Jude Donor '05-'08
Originally Posted by AU N EGL
Heat check cracks are normal
If you car shutters with hard stops a few things to look at:
1) it may be the activation of ABS, which is normal
2) brake pads are tappered
3) caliper mounting brakets are bent
4) Brake fluid may be old
5) old brake pads or glazed over ( melted) brake pads
6) combination of the above
If you car shutters with hard stops a few things to look at:
1) it may be the activation of ABS, which is normal
2) brake pads are tappered
3) caliper mounting brakets are bent
4) Brake fluid may be old
5) old brake pads or glazed over ( melted) brake pads
6) combination of the above
Stress cracks are normal. It will happen eventually to all rotors. Just watch the list above and check your rotors for cracks that are all the way through. With Road racing we will run your rotors day after day if we dont crack them all the way.
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Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
the likely of a 'warped' rotors is almost non-issue.
May be too much brake dust build on one side or part of the rotor that gives that felling of shutter. Some spay brake cleaner and a rag on both sides of the rotors to clean them off. Then go rebed the pads and rotors.
PPl who say their rotors dont crack drive differently. Not better or worse, just they dont get on the brakes hard.
Cracks are heat checks, that is all.
May be too much brake dust build on one side or part of the rotor that gives that felling of shutter. Some spay brake cleaner and a rag on both sides of the rotors to clean them off. Then go rebed the pads and rotors.
PPl who say their rotors dont crack drive differently. Not better or worse, just they dont get on the brakes hard.
Cracks are heat checks, that is all.
Melting Slicks
Joined: May 2000
Posts: 2,498
Likes: 4
From: Brentwood TN
Originally Posted by nastymant
Is this normal? All these cracks in the rotor? I bought this 98 with 75K miles on it. The car shudders bad when i brake hard at 120 mph.
Unless you have a 5 point harness and a roll cage (and probably even if you DO), a few hundred bucks or so for slotted or drilled high performance rotors and compatible pads is probably less than your hospitalization deductible and copay. If these rotors were on my car and I planned to drive more than 55 mph, they'd be gone. It may well be that others run "cracked" rotors with no problem. Good on 'em.
Safety considerations suggest that erring on the side of replacement may be a good idea. This from someone who once drove his '56 with a Z28 engine in it at 5200 rpm in high gear which calculates to something on the order of a buck forty. That was then. 
Charlie
Thread Starter
Instructor
Joined: Apr 2006
Posts: 161
Likes: 1
From: Cypress TX
alright.. thanks for the help guys..i'm leaning towards buying higher performance slotted/drilled rotors.
the first time it happened i thought something was wrong with my car, i was going 120-130 and braked hard down to about 90. i thought a tire had blown. thats how bad it was shaking. i let off the brakes and after 10 or 20 seconds it was back to normal brake feeling. i'm guessing that the previous owner had the rotors turned. less metal, more warpage.
thanks again...
the first time it happened i thought something was wrong with my car, i was going 120-130 and braked hard down to about 90. i thought a tire had blown. thats how bad it was shaking. i let off the brakes and after 10 or 20 seconds it was back to normal brake feeling. i'm guessing that the previous owner had the rotors turned. less metal, more warpage.
thanks again...
Pro
Joined: Mar 2003
Posts: 699
Likes: 0
From: Richfield MN
Originally Posted by nastymant
alright.. thanks for the help guys..i'm leaning towards buying higher performance slotted/drilled rotors.
Race Director
Joined: Dec 2000
Posts: 19,304
Likes: 85
From: San Diego CA
With other vehicles, that statement may be true, but C5 OEM-style rotors tend to collect uneven deposits of brake pad material on them, causing the dreaded pulsating brake pedal syndrome. Slotted rotors not only stay cooler, but prevent uneven deposits AND glazed pads from occuring.
Drilled rotors are more prone to cracking and should be avoided if aggressive driving is the norm.
Drilled rotors are more prone to cracking and should be avoided if aggressive driving is the norm.
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,820
From: Charlotte, NC (formerly Endicott, NY)
Originally Posted by nastymant
alright.. thanks for the help guys..i'm leaning towards buying higher performance slotted/drilled rotors.
the first time it happened i thought something was wrong with my car, i was going 120-130 and braked hard down to about 90. i thought a tire had blown. thats how bad it was shaking. i let off the brakes and after 10 or 20 seconds it was back to normal brake feeling. i'm guessing that the previous owner had the rotors turned. less metal, more warpage.
thanks again...
the first time it happened i thought something was wrong with my car, i was going 120-130 and braked hard down to about 90. i thought a tire had blown. thats how bad it was shaking. i let off the brakes and after 10 or 20 seconds it was back to normal brake feeling. i'm guessing that the previous owner had the rotors turned. less metal, more warpage.
thanks again...
If the problem goes away when you are doing normal braking you do not have a warped rotor. Warped rotors do not heal themselves or get better at low speeds.
Bill