Odd braking at high speed or hard turn and brake, ABS related>
04-11-2007, 01:49 PM
#21
VIP ...
I had C5 caliper with the C5 rotors and LGM relocation brackets and ran a wide array of brake pads.
I then went to 4 piston Brembos on the front running Porsche Motorsports black pads for the track and a Porterfield stock pad for the street.
The other 2 ...
And my subtle point is hundreds if not thousands of folks have done EXACTLY the mod you describe WITHOUT the issue you describe.
So, I still stand by my original thought is that something other than ABS and/or bias is wrong.
And for the record, I have never felt ABS as you both have described it. I'm no longr proclaiming what you feel isn't ABS, but mine never, ever acted like that.
The only time I've ever had a pedal go hard and brake performance reduce significantly is when I did a hard 90-30 brake on stock type pads. I say 30 because that's about as slow as I could get the car without evasive maneuvers. The previous 60 mph redution felt fine.
I asked about pad application because a C5 pad on an F-Body rotor will not clear the rotor hat once the pads is about 2/3 the way through it's life. The lip of the backing plate will hit the rotor hat and keep the pad from going any further down.
It was a shot in the dark.
I hope you guys figure out the problem.
I had C5 caliper with the C5 rotors and LGM relocation brackets and ran a wide array of brake pads.
I then went to 4 piston Brembos on the front running Porsche Motorsports black pads for the track and a Porterfield stock pad for the street.
The other 2 ...
And my subtle point is hundreds if not thousands of folks have done EXACTLY the mod you describe WITHOUT the issue you describe.
So, I still stand by my original thought is that something other than ABS and/or bias is wrong.
And for the record, I have never felt ABS as you both have described it. I'm no longr proclaiming what you feel isn't ABS, but mine never, ever acted like that.
The only time I've ever had a pedal go hard and brake performance reduce significantly is when I did a hard 90-30 brake on stock type pads. I say 30 because that's about as slow as I could get the car without evasive maneuvers. The previous 60 mph redution felt fine.
I asked about pad application because a C5 pad on an F-Body rotor will not clear the rotor hat once the pads is about 2/3 the way through it's life. The lip of the backing plate will hit the rotor hat and keep the pad from going any further down.
It was a shot in the dark.
I hope you guys figure out the problem.
04-11-2007, 06:13 PM
#23
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Mitchntx,
I have the same setup you did on your car, lg brackets, c5 caliper, and c5 rotor. Using Ls1 sized pads though as recommended by everyone.
I guess I have the oddball of the group, just didn't know it would have been this odd. I was thinking there is something special everyone does when they autox their car to disable the ABS sensor or to reduce its sensitivity, b/c if you hit a hard turn and your wheels start to screetch, my ABS wants to kick in if I drag the brake or even touch it.
I have the same setup you did on your car, lg brackets, c5 caliper, and c5 rotor. Using Ls1 sized pads though as recommended by everyone.
I guess I have the oddball of the group, just didn't know it would have been this odd. I was thinking there is something special everyone does when they autox their car to disable the ABS sensor or to reduce its sensitivity, b/c if you hit a hard turn and your wheels start to screetch, my ABS wants to kick in if I drag the brake or even touch it.
04-03-2023, 01:58 PM
#29
I know its an old thread but i found this while searching for my problem I'm having. This sounds exactly like whats going on with my car. I first noticed it when i took my car to the track several years ago, at the top end after crossing the finishline and attempting to rapidly brake and slow down to make the turnoff i noticed the pedal was hard and the car became difficult to slow down (only going 111 mph in the 1/4). The brakes act completely fine during normal driving, even when getting them hot in stop and go traffic it never "fades" or has a problem with lack of vacuum from the booster even with a medium sized cam..even tested the booster and it holds vacuum fine. The brakes are stock and relatively new, plenty of pad life left. But the problem only surfaces when trying to rapidly slow down (not even panic braking) from a higher speed. It feels downright scary at the track trying to stop the thing. This happened with the stock original 3.23 10 bolt (3 channel) and with the 2nd replacement 10 bolt i put in also 3 channel but with 3.42 gears. Wish there was a concrete answer 20+ years later to wtf is going on as i see several people have the same issue.
04-08-2023, 05:09 PM
#30
Had this happen to a 99 Tahoe I had, making a turn around on a boulevard or pulling into a parking spot even - abs would activate, turned out the wires going to the sensors were failing when being turned with the steering, new harnesses fixed it...those sensors would read right until it turned a specific amount then the ABS speed would drop to zero
04-26-2023, 01:20 PM
#31
Teching In
I feel your pain and almost shat myself I feel your pain and almost shat myself when it happened to me. I bought my 02 SS in 08 (4 channel ABS with traction control) and once familiar and trusting of the car I decided it was time time to top end it.
I found a very limited access 1 mile stretch of rural road with only a couple of ag field access places that only a farmer would use. The road T' ed into a county route and I figured the last 1/8 mile would be my brake point and extra for safety distance for good measure. I cruised the road twice to assure no issues would arise during my speed run. That said I ran it up to 130mph, all was well with me and the car and there was no reason to push it and went for the brakes. The plan was for an easy 1/8 mile straight line stop and no place or time for a brake test. I hit the brakes and the pedal was rock hard at about 1" pedal compression and there was no braking effect to be felt at all, NADDA . I released the pedal and stood on it again, NADDA and then again a 3rd time and NADDA and still doing 100+ and using up the 1/8 mile fast. My conscience thought was all about running out of road and the 4' ditch and the other side of the county route. Without thinking I power cycled the car and the brakes applied as normal and I stopped with some to spare. At the time i researched and even had a contact within GM that could not shed light on it. When purchased the car had a staggered set up and the front was a few inches less in circumference than the rear. I believe that the ABS freaked and algorithm was unable to handle the different circumference results at speed. With some guidance this is all we could ascertain and I put C3 10 spoke wheels and 275-40-17 on all 4 corners and life was good. UNTIL a few years later when the suspension build was complete and then I started HPD with slicks I might add. I never had the steel pedal again (including while at Road America driving 3 straights at 135+ per lap). Regardless of the track I ran I always left the TC on and what I found was that the ABS would go inoperative half way through a 20 minute session and become worse over time. I believe that the cause is an ABS module that cannot process the data fast enough for a significant front to back stagger (steel pedal results) nor the rigors of a slicks on track (no steel pedal but the ABS light came on and left with non ABS braking). Possible solutions: eliminate the stagger (i did) and I replaced the ABS module which seemed to hold up well for a few track days then performance would fall apart and ABS would disappear but normal braking was in place and strong. It always came back after a power cycle. If you are dealing with this find a buddy with a matched set of 4 tires and wheels that you can swap out then replicate the braking scenario and see what happens. I had this issue with stock brakes and a big 14" brake kit with 4 piston fixed position calipers and was assured that fluid volume was not the issue. The boys at GM must not have calculated and allowed for a significant stagger nor slicks on track when they selected the ABS module. I still have 2 E-Bay used 4 circuit ABS modules if anyone has the need. Initial stagger 275 35 18 = 25.6" dia and 295 35 18 = 26.1" dia..
I found a very limited access 1 mile stretch of rural road with only a couple of ag field access places that only a farmer would use. The road T' ed into a county route and I figured the last 1/8 mile would be my brake point and extra for safety distance for good measure. I cruised the road twice to assure no issues would arise during my speed run. That said I ran it up to 130mph, all was well with me and the car and there was no reason to push it and went for the brakes. The plan was for an easy 1/8 mile straight line stop and no place or time for a brake test. I hit the brakes and the pedal was rock hard at about 1" pedal compression and there was no braking effect to be felt at all, NADDA . I released the pedal and stood on it again, NADDA and then again a 3rd time and NADDA and still doing 100+ and using up the 1/8 mile fast. My conscience thought was all about running out of road and the 4' ditch and the other side of the county route. Without thinking I power cycled the car and the brakes applied as normal and I stopped with some to spare. At the time i researched and even had a contact within GM that could not shed light on it. When purchased the car had a staggered set up and the front was a few inches less in circumference than the rear. I believe that the ABS freaked and algorithm was unable to handle the different circumference results at speed. With some guidance this is all we could ascertain and I put C3 10 spoke wheels and 275-40-17 on all 4 corners and life was good. UNTIL a few years later when the suspension build was complete and then I started HPD with slicks I might add. I never had the steel pedal again (including while at Road America driving 3 straights at 135+ per lap). Regardless of the track I ran I always left the TC on and what I found was that the ABS would go inoperative half way through a 20 minute session and become worse over time. I believe that the cause is an ABS module that cannot process the data fast enough for a significant front to back stagger (steel pedal results) nor the rigors of a slicks on track (no steel pedal but the ABS light came on and left with non ABS braking). Possible solutions: eliminate the stagger (i did) and I replaced the ABS module which seemed to hold up well for a few track days then performance would fall apart and ABS would disappear but normal braking was in place and strong. It always came back after a power cycle. If you are dealing with this find a buddy with a matched set of 4 tires and wheels that you can swap out then replicate the braking scenario and see what happens. I had this issue with stock brakes and a big 14" brake kit with 4 piston fixed position calipers and was assured that fluid volume was not the issue. The boys at GM must not have calculated and allowed for a significant stagger nor slicks on track when they selected the ABS module. I still have 2 E-Bay used 4 circuit ABS modules if anyone has the need. Initial stagger 275 35 18 = 25.6" dia and 295 35 18 = 26.1" dia..
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BFK86 (05-03-2023)
05-03-2023, 09:53 PM
#32
I feel your pain and almost shat myself when it happened to me. I bought my 02 SS in 08 (4 channel ABS with traction control) and once familiar and trusting of the car I decided it was time time to top end it.
I found a very limited access 1 mile stretch of rural road with only a couple of ag field access places that only a farmer would use. The road T' ed into a county route and I figured the last 1/8 mile would be my brake point and extra for safety distance for good measure. I cruised the road twice to assure no issues would arise during my speed run. That said I ran it up to 130mph, all was well with me and the car and there was no reason to push it and went for the brakes. The plan was for an easy 1/8 mile straight line stop and no place or time for a brake test. I hit the brakes and the pedal was rock hard at about 1" pedal compression and there was no braking effect to be felt at all, NADDA . I released the pedal and stood on it again, NADDA and then again a 3rd time and NADDA and still doing 100+ and using up the 1/8 mile fast. My conscience thought was all about running out of road and the 4' ditch and the other side of the county route. Without thinking I power cycled the car and the brakes applied as normal and I stopped with some to spare. At the time i researched and even had a contact within GM that could not shed light on it. When purchased the car had a staggered set up and the front was a few inches less in circumference than the rear. I believe that the ABS freaked and algorithm was unable to handle the different circumference results at speed. With some guidance this is all we could ascertain and I put C3 10 spoke wheels and 275-40-17 on all 4 corners and life was good. UNTIL a few years later when the suspension build was complete and then I started HPD with slicks I might add. I never had the steel pedal again (including while at Road America driving 3 straights at 135+ per lap). Regardless of the track I ran I always left the TC on and what I found was that the ABS would go inoperative half way through a 20 minute session and become worse over time. I believe that the cause is an ABS module that cannot process the data fast enough for a significant front to back stagger (steel pedal results) nor the rigors of a slicks on track (no steel pedal but the ABS light came on and left with non ABS braking). Possible solutions: eliminate the stagger (i did) and I replaced the ABS module which seemed to hold up well for a few track days then performance would fall apart and ABS would disappear but normal braking was in place and strong. It always came back after a power cycle. If you are dealing with this find a buddy with a matched set of 4 tires and wheels that you can swap out then replicate the braking scenario and see what happens. I had this issue with stock brakes and a big 14" brake kit with 4 piston fixed position calipers and was assured that fluid volume was not the issue. The boys at GM must not have calculated and allowed for a significant stagger nor slicks on track when they selected the ABS module. I still have 2 E-Bay used 4 circuit ABS modules if anyone has the need. Initial stagger 275 35 18 = 25.6" dia and 295 35 18 = 26.1" dia..
I found a very limited access 1 mile stretch of rural road with only a couple of ag field access places that only a farmer would use. The road T' ed into a county route and I figured the last 1/8 mile would be my brake point and extra for safety distance for good measure. I cruised the road twice to assure no issues would arise during my speed run. That said I ran it up to 130mph, all was well with me and the car and there was no reason to push it and went for the brakes. The plan was for an easy 1/8 mile straight line stop and no place or time for a brake test. I hit the brakes and the pedal was rock hard at about 1" pedal compression and there was no braking effect to be felt at all, NADDA . I released the pedal and stood on it again, NADDA and then again a 3rd time and NADDA and still doing 100+ and using up the 1/8 mile fast. My conscience thought was all about running out of road and the 4' ditch and the other side of the county route. Without thinking I power cycled the car and the brakes applied as normal and I stopped with some to spare. At the time i researched and even had a contact within GM that could not shed light on it. When purchased the car had a staggered set up and the front was a few inches less in circumference than the rear. I believe that the ABS freaked and algorithm was unable to handle the different circumference results at speed. With some guidance this is all we could ascertain and I put C3 10 spoke wheels and 275-40-17 on all 4 corners and life was good. UNTIL a few years later when the suspension build was complete and then I started HPD with slicks I might add. I never had the steel pedal again (including while at Road America driving 3 straights at 135+ per lap). Regardless of the track I ran I always left the TC on and what I found was that the ABS would go inoperative half way through a 20 minute session and become worse over time. I believe that the cause is an ABS module that cannot process the data fast enough for a significant front to back stagger (steel pedal results) nor the rigors of a slicks on track (no steel pedal but the ABS light came on and left with non ABS braking). Possible solutions: eliminate the stagger (i did) and I replaced the ABS module which seemed to hold up well for a few track days then performance would fall apart and ABS would disappear but normal braking was in place and strong. It always came back after a power cycle. If you are dealing with this find a buddy with a matched set of 4 tires and wheels that you can swap out then replicate the braking scenario and see what happens. I had this issue with stock brakes and a big 14" brake kit with 4 piston fixed position calipers and was assured that fluid volume was not the issue. The boys at GM must not have calculated and allowed for a significant stagger nor slicks on track when they selected the ABS module. I still have 2 E-Bay used 4 circuit ABS modules if anyone has the need. Initial stagger 275 35 18 = 25.6" dia and 295 35 18 = 26.1" dia..
