errolmorris
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Congrats toyo.
Technical More bleeding brake woes
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Technical More bleeding brake woes
errolmorris
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Spot on. Unfortunately, most people only discover the limitations when it is too late. As you say, careful driving and experience works wonders.
My remarks about ABS and it's headaches are backed up by the following which I trawled down from the www. It's mainly regarding US systems but they are common worldwide. The text is now a few years out of date.
Report Critical of Safety Benefits of Antilock Brakes
The safety benefits of antilock brakes (ABS) have come under fire by such groups as the Highway Loss Data Institute (HLDI), who published a report that said antilock brakes are NOT reducing either the frequency or the cost of crashes.
According to the HLDI report, 1,000 fatal crashes during a 10 year period were studied to see if ABS made a difference one way or the other. The HLDI researchers found that a person in an ABS-equipped vehicle actually had a 45% greater chance of dying in a single-vehicle crash than someone in a vehicle without ABS. The chance of dying went up also went up 65% when the vehicle was involved in a single-car accident on wet pavement.
On the other hand, the report also found that multi-vehicle fatal crashes on wet roads were actually 24% lower for ABS-equipped cars, and that ABS-equipped cars killed 27% fewer pedestrians and bicyclists. But these reductions were offset by a 28% higher fatality rate involving accidents where an ABS-equipped vehicle ran off the road and rolled over.
The HLDI news release also cited a separate study that General Motors did of crashes involving ABS-equipped vehicles in two states. The GM study found that ABS-equipped vehicles had 3% fewer accidents overall but suffered a 44% increase in rollovers.
Some insurance companies have cited the HLDI study as 'evidence' that ABS does not necessarily reduce accident claims, so they can eliminate previously offered discounts for having ABS on a vehicle.
The National Highway Traffic Safety Administration (NHTSA) said the HLDI report findings may be explained by several factors: that drivers who are unfamiliar with ABS may not keep their foot on the brake or may pump the pedal during a panic stop, reducing the effectiveness of the ABS system. ABS may also give some drivers a false sense of security, possibly encouraging them to drive more aggressively and run off the road.
Shortly after the HLDI report was released, two auto industry associations released a study of their own that said people who drive ABS-equipped vehicles actually suffer fewer injuries, and that the overall accident rate for ABS-equipped vehicles is about 10% less than that for vehicles without ABS. The overall fatality rate, however, was found to be no different.
Responding to the negative reports, four ABS manufacturers (Bosch, Delphi, Continental Teves and Kelsey-Hayes) formed a group called the ABS Education Alliance and did their own analysis of the numbers. The Alliance found that vehicles equipped with four-wheel ABS systems were involved in 2,800 fewer frontal impacts (a category that accounts for 82% of the crashes analyzed by the NHTSA).
The ABS Education Alliance also launched the 'America brakes for safety' campaign to help motorists learn how to use antilock brakes properly, like not pumping the pedal when braking hard, remembering to steer while braking to avoid an accident, having their ABS system checked if the ABS warning lamp is on.
GROWTH OF ABS HAS LEVELLED OFF
For awhile, it seemed as if all cars and trucks would eventually have ABS as standard equipment. But in spite of the rapid growth of ABS availability in the early 1990s, the number of vehicles equipped with ABS has been static.
Since 1994, the percentage of domestically produced vehicles actually equipped with ABS has been about 58%.
Though ABS systems keep coming down in price and are getting better every year, the vehicle manufacturers say it is still an expensive option that many consumers are not willing to pay for. Consumers would rather have options such as air conditioning and a high end sound system than ABS. Consequently, the auto makers have been shipping models loaded with options other than ABS to their dealers, thus limiting the public's ability to buy an ABS-equipped vehicle even if they wanted the safety feature.
ABS LEGAL BATTLES & RECALLS
General Motors and Chrysler have both had their share of ABS legal hassles. The RWAL rear-wheel ABS system manufactured by Kelsey-Hayes and used on various 1989 to 1996 Chevrolet and GMC trucks has been under investigation by the NHTSA for a variety of complaints including loss of pedal, excessive pedal travel, failure to stop the vehicle under certain conditions, and excessive front pad wear. Since 1994, NHTSA has reportedly received over 10,000 complaints on ABS problems with GMC and Chevy trucks. A class action suit filed against GM and Kelsey-Hayes on behalf of owners of these vehicles was dismissed August 1, 1997. NHTSA has taken no action of its own, but GM did do a voluntary recall of 1.1 million Chevy and GMC trucks with the Kelsey-Hayes EBC4 ABS system. The recalled models include 1991-1996 four-wheel drive Blazer, Jimmy, S-10 and GMC Sonoma, 1992-1995 Chevy Astro vans and GMC Safari vans, and 1993-1996 G-Series vans.
The Bendix 10 ABS system used on 1991-93 Chrysler minivans (Dodge Caravan, Plymouth Voyager & Chrysler Town & Country), Chrysler New Yorker, Imperial and Dynasty, and 1991-92 Eagle Premier and Dodge Monaco, came under fire for reportedly experiencing a high ABS pump failure rate. The NHTSA reportedly received nearly 2,000 complaints about problems with this particular ABS system, including numerous accidents and injuries (but no deaths). The NHTSA investigation found that most complaints centered on the pedal sinking to the floor causing a loss of brakes. The condition is often intermittent and occurs without warning.
The NHTSA investigation of the Chrysler Bendix 10 ABS problem resulted in a safety recall (#685) being issued in August 1996. The recall listed the ABS actuator piston and pump/motor assembly as the culprit. The recall notice issued to Chrysler dealers specified a test procedure for checking out the Bendix 10 ABS system:
1. Check for trouble codes.
2. If none are found, depressurize the accumulator by pumping the brake pedal 40 times with the ignition off, then install a special leakage test fixture (#6997) to test system pressure and to check for leaks. Pump pressure should build to 1800 to 2200 psi, then shut off. Pressure should hold and drop less than 200 psi in two minutes.
If the system builds adequate pressure, but the hydraulic control unit side of the system drops more than 200 psi in two minutes, the master cylinder actuator piston assembly needs to be replaced.
If the system builds adequate pressure but the pump/motor side of the system drops more than 200 psi in two minutes, the pump/motor assembly needs to be replaced.
In addition to sending out a recall notice to all the owners of the affected vehicles, Chrysler also extended the warranty on the ABS system components to 10 years or 100,000 miles. The extended warranty applies to the ABS components only and not the entire brake system.
Antilock Brake Safety Precautions on Late Model Cars
A growing number of late model cars are equipped with antilock brake systems that can precharge the brakes in anticipation of braking (to reduce braking reaction time), or actually apply the brakes automatically as a function of the collision prevention system (automatic braking).
CAUTION: If you are doing any type of brake work on these vehicles, the braking system must be deactivated before you work on the brakes, otherwise the system may energize the brakes unexpectedly causing the caliper pistons to push outward with considerable force. This could pinch your fingers if they are between the pads and rotors. If the pads have been removed, the pistons can blow out of their calipers. This can happen even when the ignition and engine are off!
The antilock brake system can be deactivated by locating and removing the main power fuse for the ABS system, or by using a scan tool to temporarily deactivate the system. Disconnecting the battery also works, but this may cause loss of certain memory settings in various vehicle modules.
Report Critical of Safety Benefits of Antilock Brakes
The safety benefits of antilock brakes (ABS) have come under fire by such groups as the Highway Loss Data Institute (HLDI), who published a report that said antilock brakes are NOT reducing either the frequency or the cost of crashes.
According to the HLDI report, 1,000 fatal crashes during a 10 year period were studied to see if ABS made a difference one way or the other. The HLDI researchers found that a person in an ABS-equipped vehicle actually had a 45% greater chance of dying in a single-vehicle crash than someone in a vehicle without ABS. The chance of dying went up also went up 65% when the vehicle was involved in a single-car accident on wet pavement.
On the other hand, the report also found that multi-vehicle fatal crashes on wet roads were actually 24% lower for ABS-equipped cars, and that ABS-equipped cars killed 27% fewer pedestrians and bicyclists. But these reductions were offset by a 28% higher fatality rate involving accidents where an ABS-equipped vehicle ran off the road and rolled over.
The HLDI news release also cited a separate study that General Motors did of crashes involving ABS-equipped vehicles in two states. The GM study found that ABS-equipped vehicles had 3% fewer accidents overall but suffered a 44% increase in rollovers.
Some insurance companies have cited the HLDI study as 'evidence' that ABS does not necessarily reduce accident claims, so they can eliminate previously offered discounts for having ABS on a vehicle.
The National Highway Traffic Safety Administration (NHTSA) said the HLDI report findings may be explained by several factors: that drivers who are unfamiliar with ABS may not keep their foot on the brake or may pump the pedal during a panic stop, reducing the effectiveness of the ABS system. ABS may also give some drivers a false sense of security, possibly encouraging them to drive more aggressively and run off the road.
Shortly after the HLDI report was released, two auto industry associations released a study of their own that said people who drive ABS-equipped vehicles actually suffer fewer injuries, and that the overall accident rate for ABS-equipped vehicles is about 10% less than that for vehicles without ABS. The overall fatality rate, however, was found to be no different.
Responding to the negative reports, four ABS manufacturers (Bosch, Delphi, Continental Teves and Kelsey-Hayes) formed a group called the ABS Education Alliance and did their own analysis of the numbers. The Alliance found that vehicles equipped with four-wheel ABS systems were involved in 2,800 fewer frontal impacts (a category that accounts for 82% of the crashes analyzed by the NHTSA).
The ABS Education Alliance also launched the 'America brakes for safety' campaign to help motorists learn how to use antilock brakes properly, like not pumping the pedal when braking hard, remembering to steer while braking to avoid an accident, having their ABS system checked if the ABS warning lamp is on.
GROWTH OF ABS HAS LEVELLED OFF
For awhile, it seemed as if all cars and trucks would eventually have ABS as standard equipment. But in spite of the rapid growth of ABS availability in the early 1990s, the number of vehicles equipped with ABS has been static.
Since 1994, the percentage of domestically produced vehicles actually equipped with ABS has been about 58%.
Though ABS systems keep coming down in price and are getting better every year, the vehicle manufacturers say it is still an expensive option that many consumers are not willing to pay for. Consumers would rather have options such as air conditioning and a high end sound system than ABS. Consequently, the auto makers have been shipping models loaded with options other than ABS to their dealers, thus limiting the public's ability to buy an ABS-equipped vehicle even if they wanted the safety feature.
ABS LEGAL BATTLES & RECALLS
General Motors and Chrysler have both had their share of ABS legal hassles. The RWAL rear-wheel ABS system manufactured by Kelsey-Hayes and used on various 1989 to 1996 Chevrolet and GMC trucks has been under investigation by the NHTSA for a variety of complaints including loss of pedal, excessive pedal travel, failure to stop the vehicle under certain conditions, and excessive front pad wear. Since 1994, NHTSA has reportedly received over 10,000 complaints on ABS problems with GMC and Chevy trucks. A class action suit filed against GM and Kelsey-Hayes on behalf of owners of these vehicles was dismissed August 1, 1997. NHTSA has taken no action of its own, but GM did do a voluntary recall of 1.1 million Chevy and GMC trucks with the Kelsey-Hayes EBC4 ABS system. The recalled models include 1991-1996 four-wheel drive Blazer, Jimmy, S-10 and GMC Sonoma, 1992-1995 Chevy Astro vans and GMC Safari vans, and 1993-1996 G-Series vans.
The Bendix 10 ABS system used on 1991-93 Chrysler minivans (Dodge Caravan, Plymouth Voyager & Chrysler Town & Country), Chrysler New Yorker, Imperial and Dynasty, and 1991-92 Eagle Premier and Dodge Monaco, came under fire for reportedly experiencing a high ABS pump failure rate. The NHTSA reportedly received nearly 2,000 complaints about problems with this particular ABS system, including numerous accidents and injuries (but no deaths). The NHTSA investigation found that most complaints centered on the pedal sinking to the floor causing a loss of brakes. The condition is often intermittent and occurs without warning.
The NHTSA investigation of the Chrysler Bendix 10 ABS problem resulted in a safety recall (#685) being issued in August 1996. The recall listed the ABS actuator piston and pump/motor assembly as the culprit. The recall notice issued to Chrysler dealers specified a test procedure for checking out the Bendix 10 ABS system:
1. Check for trouble codes.
2. If none are found, depressurize the accumulator by pumping the brake pedal 40 times with the ignition off, then install a special leakage test fixture (#6997) to test system pressure and to check for leaks. Pump pressure should build to 1800 to 2200 psi, then shut off. Pressure should hold and drop less than 200 psi in two minutes.
If the system builds adequate pressure, but the hydraulic control unit side of the system drops more than 200 psi in two minutes, the master cylinder actuator piston assembly needs to be replaced.
If the system builds adequate pressure but the pump/motor side of the system drops more than 200 psi in two minutes, the pump/motor assembly needs to be replaced.
In addition to sending out a recall notice to all the owners of the affected vehicles, Chrysler also extended the warranty on the ABS system components to 10 years or 100,000 miles. The extended warranty applies to the ABS components only and not the entire brake system.
Antilock Brake Safety Precautions on Late Model Cars
A growing number of late model cars are equipped with antilock brake systems that can precharge the brakes in anticipation of braking (to reduce braking reaction time), or actually apply the brakes automatically as a function of the collision prevention system (automatic braking).
CAUTION: If you are doing any type of brake work on these vehicles, the braking system must be deactivated before you work on the brakes, otherwise the system may energize the brakes unexpectedly causing the caliper pistons to push outward with considerable force. This could pinch your fingers if they are between the pads and rotors. If the pads have been removed, the pistons can blow out of their calipers. This can happen even when the ignition and engine are off!
The antilock brake system can be deactivated by locating and removing the main power fuse for the ABS system, or by using a scan tool to temporarily deactivate the system. Disconnecting the battery also works, but this may cause loss of certain memory settings in various vehicle modules.
errolmorris
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That report is in line with a Monash report carried out here in Australia some years ago.
Manufacturers regularly issue service bulletins here in Australia, with the exception of certain ABS warnings and some other 'very minor' safety issues, and instead rely on phone calls.
They say it is not a bulletin issue and therefore there is no legal requirement to report the issue especially when control is in the hands of the operator of the vehicle.
In other words, you really need to be trained in the use of these 'safety' devices. In Australia, people are taught how to obtain a driver license, they are not taught to drive a motor vehicle safely. If one wants to 'learn to drive', then one will need deep pockets.
My opinion is that it (ABS) is a wonderful piece of technology for vehicles that travel at speeds below 60kph on well tended bitumen roads.
ESP is another story altogether.
Manufacturers regularly issue service bulletins here in Australia, with the exception of certain ABS warnings and some other 'very minor' safety issues, and instead rely on phone calls.
They say it is not a bulletin issue and therefore there is no legal requirement to report the issue especially when control is in the hands of the operator of the vehicle.
In other words, you really need to be trained in the use of these 'safety' devices. In Australia, people are taught how to obtain a driver license, they are not taught to drive a motor vehicle safely. If one wants to 'learn to drive', then one will need deep pockets.
My opinion is that it (ABS) is a wonderful piece of technology for vehicles that travel at speeds below 60kph on well tended bitumen roads.
ESP is another story altogether.
99.99% of accidents are non fatal, writing off abs on the basis of fatal accidents is ridiculous. Some studies show an increase in fatalities but most show positive effects on number of accidents, number and severity of injuries.
The updated hertz data in the monash report showed that for vans and trucks with all wheel abs all types of non fatal accident were reduced, most significantly while fatal accidents were increased. The conclusion of the monash study like most others was that any increase in accidents was due to human factors.
The updated hertz data in the monash report showed that for vans and trucks with all wheel abs all types of non fatal accident were reduced, most significantly while fatal accidents were increased. The conclusion of the monash study like most others was that any increase in accidents was due to human factors.
errolmorris
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"...due to human factors.", which is exactly what I said, although fatalities is yet another issue altogether and I make no reference to this since no studies have been able to be conducted given the lack of information available.
As an example, a suicide involving a motor vehicle in Austalia is a 'motor vehicle statistic', a vehicle on a farm or other private property which crashes, for whatever reason, is a 'motor vehicle statistic' and if a person is injured or dies whilst sitting in or on a motorised vehicle, this includes ride on mowers and other motorised instruments, these also come under 'motor vehicle statistics'. As you can see, there is no way to garner explicit information from the plethora of sources other than to say, as I have previously mentioned as did the earlier writer, that it all comes down to driver behaviour/education.
Anecdotal evidence is of little use, but does allow a starting point for scientific evaluation.
My involvement in this field has been over a 38 year period and even the information I have points to lack of information/education of operators of said vehicles and instruments.
99.99% of accidents are non fatal, writing off abs on the basis of fatal accidents is ridiculous.
This statement is a little inflammatory and totally inaccurate in that no one on this forum has made any such suggestion or intimation in regards to 'fatal accidents' and the figure of '99.9% of accidents are non fatal' is very likely your interpretation.
My rant is complete and I will not be drawn into any arguments on figures/information published by any group or body or individual that is not a peer reviewed scientific publication.
As an example, a suicide involving a motor vehicle in Austalia is a 'motor vehicle statistic', a vehicle on a farm or other private property which crashes, for whatever reason, is a 'motor vehicle statistic' and if a person is injured or dies whilst sitting in or on a motorised vehicle, this includes ride on mowers and other motorised instruments, these also come under 'motor vehicle statistics'. As you can see, there is no way to garner explicit information from the plethora of sources other than to say, as I have previously mentioned as did the earlier writer, that it all comes down to driver behaviour/education.
Anecdotal evidence is of little use, but does allow a starting point for scientific evaluation.
My involvement in this field has been over a 38 year period and even the information I have points to lack of information/education of operators of said vehicles and instruments.
99.99% of accidents are non fatal, writing off abs on the basis of fatal accidents is ridiculous.
This statement is a little inflammatory and totally inaccurate in that no one on this forum has made any such suggestion or intimation in regards to 'fatal accidents' and the figure of '99.9% of accidents are non fatal' is very likely your interpretation.
My rant is complete and I will not be drawn into any arguments on figures/information published by any group or body or individual that is not a peer reviewed scientific publication.
The quoted HLDI report is based completely on fatal accidents and most negative findings in subsequent reports including the Monash report you mentioned were based on fatal accidents.
It was mental estimate based on published figures. Here are some real figures from a quick google.
US "In 2010, there were an estimated 5,419,000 crashes (30,296 fatal crashes)" http://www-fars.nhtsa.dot.gov/Main/index.aspx
99.44% non fatal
UK only record personal injury accidents reported by police which is a fraction of the total accidents and the EU has raised concern about UK underreporting. Rospa estimates real non fatal figures are more than three times the reported figures.
"A total of 146,322 personal-injury road traffic accidents were
reported to the police in 2014. Of these accidents, 1,658 resulted in at least one fatality"
https://www.gov.uk/government/statistics/reported-road-casualties-great-britain-annual-report-2014
98.86% non fatal
The real figure would be something like 99.7% following rospa's estimates of underreporting of accidents involving non fatal injuries.
http://www.rospa.com/road-safety/advice/roads/engineering/
ABS is an aid. Maximum retardation is just prior to lock up. Older drivers will remember cadence braking which ABS replicates much better and faster than a human. As an aid to safer vehicles it is great but there is no substitute for good driving manner and reading the road ahead. Thank fully I very seldom activate my ABS.
errolmorris
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Figures supplied by self-interest groups can not be relied upon for scientific evaluation or factual analysis and any scrutiny could well impede their funding sources, but they are safe because analysis and evaluation would require 'actual' figures, which are difficult to access, as opposed to estimates given in conflicting guesstimates of numbers and percentages.
For the mathematically challenged it all adds up.
This whole thing is based more on a 'belief system' and interpretation, which makes factual information irrelevant and therefore a sensible discussion, impossible.
For the mathematically challenged it all adds up.
This whole thing is based more on a 'belief system' and interpretation, which makes factual information irrelevant and therefore a sensible discussion, impossible.
I have been driving since 1964 without any accident worse than a scraped wing or sill, motorcycles, cars, buses of all types, heavy goods including trailers. I spent the final 8 years before retirement driving a 50-ton 5-axle concrete mixer. Top of my list for my continued safety and that of those around me on the road are:-
1. Good tyres at good pressures.
2. Clean glass and mirrors well adjusted.
3. Serviceable wiper rubbers.
4. Effective headlamps.
5. Effective brakes.
6. Good power steering.
7. Good seating and seat well adjusted.
8. Very loud air horns.
There are other factors of importance obviously, but the above, in various orders of importance depending on conditions and speed, are my top requirements.
ABS does not figure, and the ABS on my Jeep does not work and I am not losing any sleep over it, for the time being at least. The next test is 18 months away.
1. Good tyres at good pressures.
2. Clean glass and mirrors well adjusted.
3. Serviceable wiper rubbers.
4. Effective headlamps.
5. Effective brakes.
6. Good power steering.
7. Good seating and seat well adjusted.
8. Very loud air horns.
There are other factors of importance obviously, but the above, in various orders of importance depending on conditions and speed, are my top requirements.
ABS does not figure, and the ABS on my Jeep does not work and I am not losing any sleep over it, for the time being at least. The next test is 18 months away.
