Brake rotors
GeoRandy
10-13-2007, 10:36 AM
My brake rotors need to be turned often to eliminate bouncing to a stop even slowing. Especially bad at highway speeds. Mechanic at GM told me the rotors get hot and warp. Is this a problem common to all Astro/Safari vans? If that is true what kind of racing style (slotted, drilled) heat resistant or heat dissapating rotors can I use on my 2005 Safari? I'd rather pay the money for better rotors that won't warp than keep having to turn the rotors and keep replacing them. Any help will be appreciated.
ericn1300
10-13-2007, 06:18 PM
My brake rotors need to be turned often to eliminate bouncing to a stop even slowing. Especially bad at highway speeds. Mechanic at GM told me the rotors get hot and warp. Is this a problem common to all Astro/Safari vans? If that is true what kind of racing style (slotted, drilled) heat resistant or heat dissapating rotors can I use on my 2005 Safari? I'd rather pay the money for better rotors that won't warp than keep having to turn the rotors and keep replacing them. Any help will be appreciated.
How often do you have to turn them? GM OEM rotors should be fine for normal driving. About the only way they could get hot enough in normal driving to warp is if you have a stuck caliper or you're riding the brakes. I'd have say get your foot off the brake pedal, make the mental effort to keep your left foot on the floorboard and away from the pedal until you need to brake. My dad has the same problem.
How often do you have to turn them? GM OEM rotors should be fine for normal driving. About the only way they could get hot enough in normal driving to warp is if you have a stuck caliper or you're riding the brakes. I'd have say get your foot off the brake pedal, make the mental effort to keep your left foot on the floorboard and away from the pedal until you need to brake. My dad has the same problem.
old_master
10-14-2007, 03:41 PM
If the rear brakes are out of adjustment, and/or working less than they should, the front rotors and pads will overheat. Overheating alone will not cause the front brakes to surge, (pulsate) when stopping, there's a little more to it.
Fairly recent technology has determined what actually causes the surge. Before semi metallic, carbon metallic, and ceramic pads were introduced; disc brake surging was unheard of. Surging from disc brakes is caused by metal transfer from the pad to the rotor. When a vehicle comes to a hard stop, the heat that is generated softens the friction material. When you leave your foot on the brake pedal after the vehicle comes to a complete stop, the metallic material in the pad can and does bond to the rotor as the rotors and pads cool. The metal that is bonded to the rotor causes an irregularity in the braking surface of the rotor. Each time the pad contacts that area of the rotor; it causes a surge due to the difference in friction ability.
Checking axial run out of the rotors can confirm a bent rotor, but will not identify metal transfer. If a rotor has excessive axial run out, (bent) each time the brakes are applied, the caliper will slide inboard and outboard on its guides as the pads follow the surface of the rotor. When this happens, it does not cause a surge because the friction surface of the rotor is uniform. Most likely you'll notice a rattle or squeal noise from the calipers sliding back and forth. Resurfacing the rotor provides a smooth, uniform surface and removes all traces of metal transfer, and corrects imperfections in axial run out eliminating the surge... until the driver stops hard and leaves his foot on the pedal, and the process starts over.
As Eric mentioned, OEM rotors are fine. Make sure the entire brake system is operating correctly, and that you reduce, or eliminate, brake pedal pressure when stopped, (shift to neutral if necessary). The easier you are on your brakes, the fewer problems you’ll have with them.
Fairly recent technology has determined what actually causes the surge. Before semi metallic, carbon metallic, and ceramic pads were introduced; disc brake surging was unheard of. Surging from disc brakes is caused by metal transfer from the pad to the rotor. When a vehicle comes to a hard stop, the heat that is generated softens the friction material. When you leave your foot on the brake pedal after the vehicle comes to a complete stop, the metallic material in the pad can and does bond to the rotor as the rotors and pads cool. The metal that is bonded to the rotor causes an irregularity in the braking surface of the rotor. Each time the pad contacts that area of the rotor; it causes a surge due to the difference in friction ability.
Checking axial run out of the rotors can confirm a bent rotor, but will not identify metal transfer. If a rotor has excessive axial run out, (bent) each time the brakes are applied, the caliper will slide inboard and outboard on its guides as the pads follow the surface of the rotor. When this happens, it does not cause a surge because the friction surface of the rotor is uniform. Most likely you'll notice a rattle or squeal noise from the calipers sliding back and forth. Resurfacing the rotor provides a smooth, uniform surface and removes all traces of metal transfer, and corrects imperfections in axial run out eliminating the surge... until the driver stops hard and leaves his foot on the pedal, and the process starts over.
As Eric mentioned, OEM rotors are fine. Make sure the entire brake system is operating correctly, and that you reduce, or eliminate, brake pedal pressure when stopped, (shift to neutral if necessary). The easier you are on your brakes, the fewer problems you’ll have with them.
louie vulgar
10-15-2007, 10:25 PM
i have a 2000 astro and have experienced similar problems and i installed Powerslot rotors on the front that are cryo-treated and cryo treated drums on the rear. I can honestly say they have made a huge difference!
GeoRandy
10-17-2007, 05:04 PM
Thanks for the responses ericn1300, old master, and louie vulgar,
My Safari is a 2005 model that we bought from the dealser and they have done all the service work, even oil changes. I've chosen to have them do the work so if anything goes wrong they have been the only mechanics to work on it. Thanks for the feedback ericn1300, but I am always careful not to ride the brakes and cause this problem, and it is becoming a yearly thing. It is not my first Safari/Astro van and I've noticed the same thing with the two others I've had. I was just hoping that GM had solved the problem when they reworked the front end on these models and changed to the 16 inch wheels, by the way the turning radius sucks on these late models. Thanks old master for the education, I appreciate it. And
Louie, where did you get the Powerslot rotors and what should I expect to pay for them?
My Safari is a 2005 model that we bought from the dealser and they have done all the service work, even oil changes. I've chosen to have them do the work so if anything goes wrong they have been the only mechanics to work on it. Thanks for the feedback ericn1300, but I am always careful not to ride the brakes and cause this problem, and it is becoming a yearly thing. It is not my first Safari/Astro van and I've noticed the same thing with the two others I've had. I was just hoping that GM had solved the problem when they reworked the front end on these models and changed to the 16 inch wheels, by the way the turning radius sucks on these late models. Thanks old master for the education, I appreciate it. And
Louie, where did you get the Powerslot rotors and what should I expect to pay for them?
louie vulgar
10-17-2007, 08:15 PM
hey, i purchased them at www.autoanything.com (http://www.autoanything.com) they were about 160.00 each because of the cryo-treatment. I think 125.00 just regular powerslot. The rear were treated by a local cryogenics company, I don't know whats available where you live. good luck.
drew300
10-31-2007, 09:48 AM
Maybe too late to reply.
The rotors on my '97 rusted so bad internally that the rotor was collapsing when the brakes were applied.
Luckily, the company that was going to turn them found it.
The rotors on my '97 rusted so bad internally that the rotor was collapsing when the brakes were applied.
Luckily, the company that was going to turn them found it.
saturnguy2
11-01-2007, 07:09 AM
GM had fixed the problem, they stopped making Astro Vans.
It's no wonder GM is having problems and losing market share with the crap they continue to build.
It's no wonder GM is having problems and losing market share with the crap they continue to build.
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