I am familiar with the shaking associated when braking on a slick surface. I have had that same shaking effect on dry surfaces when the wheels are turned at an angle. Example: pulling into a parking space. Should I be concerned?
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2004 Subaru Forester Question: Anti lock brakes
Answer #1matte December 31, 2008, 12:00Master
That shudder associated with anti-lock brakes should only occur under circumstances when you are braking very hard and the wheels are starting to lock up. Wet conditions are a great example of when it happens more frequently.
It is unlikely that the ABS system is coming into play when you are parking, which is probably at low speeds. Since you say that it happens only when the wheels are turned, it could be a problem with a steering component or a suspension component, and not be related to the brakes at all.
If it happens every time, it should be easy for a good technician to diagnose and fix.
ReplyTim Miller, December 31, 2008, 12:30Rookie
The first time it happened the wheel were straight and the shaking was accompanied with a strange sound. Like a spring or a single note on a trumpet. This is while I was on a trip and drove more than 200 miles home with no incidents. The next day I took the car out and it happened to a slighter degree when I was pulling into a parking spot.
patrick mannion from Greg Solow's Engine Room, January 09, 2009, 16:57Master
I would agree with Matt. ABS actuation should not occur when you are turning into a parking space at a normal speed. Brake pedal pulsation will occur during normal ABS application, but is not to be confused with vibration experienced due to "brake rotors that are out of true"
My reason for adding this comment is you had commented you heard a noise like a "spring" when turning. I wonder if this noise is a brake pad wear indicator finger that is starting to make contact with the disc. Perhaps your brake pads should also be looked at while inspecting the ABS system.
ReplyTim Miller, January 09, 2009, 17:03Rookie
I went to a subaru dealer and was able to reproduce the sound in reverse with the wheels straight. His first comment was........cracked tone ring. I had a rear wheel bearing replaced just prior to these symptoms. Perhaps the tone ring was cracked upon replacement which is rather delicate.
Replypatrick mannion, January 09, 2009, 20:44Master
Tim, did the dealer indeed find a cracked tone ring and if so did replacing the tone ring or axle assembly fix the problem? I would have thought a cracked tone ring would give an erratic wheel speed sensor pattern causing the ABS light to illuminate. By the way I have replaced a lot of rear wheel bearings on those Foresters seems to have been some what of a problem.
ReplyTim Miller, January 10, 2009, 04:51Rookie
This is the second rear wheel bearing that I had replaced. The other was in a 2001 Forester, so I was familiar with the sound as soon as I heard it. The tone ring issue has not been addressed yet. I am taking it in to be further diagnosed on Tue Jan 13. The technician that mentioned it could be a cracked tone ring did so during a road test only. At that time he mentioned that since I just had a wheel bearing replaced, and they crack very easily, this could possibly be engaging the abs system prematurely. Also, when I had the bearing replaced at the dealer, (by the way it was an out of town dealer while I was away for the holidays), they do a 27 point safety check which includes looking at the brake pads. Nothing was found to be out of order.
ReplyVisitor, January 16, 2011, 16:35
I Had all the wheel bearings replaced ( for the 2nd time) on my wife's 2004 Forester after 3 of the 4 needed to be replaced. After the new bearings were installed the car road better but still had a slight rumble at highway speeds and the rear ABS would intermittently engage at very slow speeds, about 3 to 10 mph, when slowing to a stop, ex. parking. The ABS light did not light. Turns out the right rear wheel bearing was not pressed all the way in resulting in the air gap between the tone ring and ABS wheel magnet sensor being to large sending a false wheel lock up reading to the ABS computer. The ABS wheel sensor is always counting the teeth of the tone ring as they pass the sensor. If the sensor can not see the ring teeth consistently it causes problems. The snap ring was also missing. Fix could have been to just press the bearing further in but the mechanic chose to start from scratch and replaced the bearing, 3 seals, and snap ring after cleaning everything. The wheel sensors were also cleaned of debris and rust particles. So far so good. Pressing the new R/ rear bearing in correctly restored the correct air gap between the tone ring and sensor. If the air gap is to large the symptoms can be the same as a cracked,dirty or warped tone ring. I normally do all my own work but had a different mechanic from the first one do it in his shop because it is snowing and 10F. outside and I don't have a press. The new mechanic stressed that Subaru bearings don't last and when they are replaced everything needs to be clean and carefully reassembled and torqued. When it first happened my wife described the noise as a 'spring unwinding' in the right front corner of the engine bay. What she heard was the ABS motor and actuator responding as designed even though the activation was from an errant signal from the ABS sensor.
Answer #3Heathyvt April 22, 2010, 08:49Rookie
To determine if its the ABS or Tone Ring, Pull the fuse for ABS and try to reproduce the the sound. With the Fuse Removed ABS will no longer be active.
ReplyVisitor, May 29, 2010, 11:49
i have the same problem,the car vibrates as i brake slowly,the ABS light is not on and i tried pulling the ABS fuse out and it didnt stoop doing so,the light just went on,i have had my passenger rear bearing replaced recently..what could be wrong??
Answer #4moonie5353 December 22, 2010, 10:53Rookie
This also happened with our 95 Subaru Impreza ,after awhile the system started to lock the brakes open leaving us with no brakes and our mechanic told us to pull the fuse on it