Joe719 Posted December 22, 2005 Share Posted December 22, 2005 Hey all, New poster here and a second time Subaru owner. I currently have a '03 Legacy H3 and I have a question about the anti lock break system. My driveway is currently covered with ice so I thought I would test things out. I got to about 15 MPH and hit the breaks hard. The car stopped fine and stayed completely straight. I felt the "chattering" on the pedal that is supposed to be there ...right?... but I also heard a whirring type of sound almost like a small electric motor running. That is the noise I am not familiar with. Can anyone give me some information on this? If you guys are like any of the other boards I visit (Harley Davidson, 1911's, garden tractors just to name a couple) someone will have a answer for me. Thanks in advance Joe719 Quote Link to comment Share on other sites More sharing options...
Subie Gal Posted December 22, 2005 Share Posted December 22, 2005 whirring sound = abs motor pulsing in brakes = normal abs behavior skidding is a straight line = car doing what you are telling it to do you can also brake under full abs lock and STEER at the same time that's the beauty of it. a full, controlled stop. cheers, Jamie Quote Link to comment Share on other sites More sharing options...
Setright Posted December 23, 2005 Share Posted December 23, 2005 Yep, that ABS motor in the Hitachi system is very noisy! The Bosch system in my 1990 Legacy was relatively quiet. Quote Link to comment Share on other sites More sharing options...
OB99W Posted December 23, 2005 Share Posted December 23, 2005 Yep, that ABS motor in the Hitachi system is very noisy! Not that it's important, but are you sure that model doesn't have a Bosch? My info says the 97-03 Legacys have Bosch 5.3i ABS, the motor of which isn't inaudible. --OB99W Quote Link to comment Share on other sites More sharing options...
nipper Posted December 23, 2005 Share Posted December 23, 2005 This goes under the heading of "turn up the radio". The electric motor runs the dodads in the ABS system. The ABS worked as it should, on the one surface that is tough for ABS to deal with. SOunds like you have great tires. nipper Quote Link to comment Share on other sites More sharing options...
Setright Posted December 24, 2005 Share Posted December 24, 2005 YEssir! Unless Bosch has started etching "Hitachi" into the metal housing (My car is a euro spec Impreza) Quote Link to comment Share on other sites More sharing options...
OB99W Posted December 24, 2005 Share Posted December 24, 2005 (My car is a euro spec Impreza) Hmmm, the OP mentioned " '03 Legacy ", but this is hardly worth debating, especially since the ABS operation is likely normal. --OB99W Quote Link to comment Share on other sites More sharing options...
rickdabrewer Posted February 3, 2006 Share Posted February 3, 2006 We have a '98 outback and my wife is experiencing the chatter of the abs system when she is trying to stop on ice. however she doesn't always stop in a timely manner and has gone thru a couple of stop signs. the chatter on the brake peddle almost feels like it is pushing back on you. is this normal? is it her driving that sends her thru the stops? she does have control of the car but it is slow to stop. Should we have this checked out? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted February 3, 2006 Share Posted February 3, 2006 trying to stop on ice. there's no magic pill for doing that. probably normal, there is no substitute for safe driving on ice. lots of things help, but there is no way to retain summer performance on ice. Quote Link to comment Share on other sites More sharing options...
nipper Posted February 3, 2006 Share Posted February 3, 2006 ABS does not work on ice if all 4 tires lock up. Nothing works on ice except studed snow tires. This is something that is stated over and over by car manufacturers and when ever abs is tested. Only thing that works on ice is studed snow tires. ABS allows the driver to stop the car more safley, not in a shorter distance. ABS also requires at least one tire to be spinning to tell the ABS computer thats omehting is wrong. If all four wheels lock up (ice) the abs computer thinks the car has reached a full stop and therefor does not have anything to do. The trade off made with abs for being able to keep the car under control is a longer braking distance. All this is assumed as long as one out of four four tires maintain traction, or keeps rotating. You still have to brake sooner, drive slower, and be more aware of your surroundings then on dry roads. nipper . Quote Link to comment Share on other sites More sharing options...
cookie Posted February 3, 2006 Share Posted February 3, 2006 When you hear the chattering and feel the brake pedal pulseing the ABS is working. It can't do miracles but it does make it a bit more likely to steer. One has to exercise caution on ice and begin to stop much furthur back. Quote Link to comment Share on other sites More sharing options...
Setright Posted February 3, 2006 Share Posted February 3, 2006 Nipper, that's not true anymore. There's an accelerometer ("G-sensor") under the gearstick housing inside the cabin to keep track of the true speed and deceleration of the car. It IS true that Ford's early system - as fitted to the 1984 Scorpio/Granada/Falcon - had no G-sensor. That's how Leonard Setright succeeded in locking all four wheels during the press launch. Poor Ford... Quote Link to comment Share on other sites More sharing options...
nipper Posted February 3, 2006 Share Posted February 3, 2006 Nipper, that's not true anymore. There's an accelerometer ("G-sensor") under the gearstick housing inside the cabin to keep track of the true speed and deceleration of the car. It IS true that Ford's early system - as fitted to the 1984 Scorpio/Granada/Falcon - had no G-sensor. That's how Leonard Setright succeeded in locking all four wheels during the press launch. Poor Ford... but if there is no traction, there are no G's, as there is no deceleration, so it wont work. I used to work with G-snsors and all sorts of equipment when i worked for a defense contractor. you need to have at least one wheel grip to feel any gs, or feel initial deceleration as the tirs grab, brakes work, then loose traction. On ice you may never have that initial deceleration. nipper Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.