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2000 Lancaster 2.5L
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29 Posts
Discussion Starter #1
Every morning I reverse onto my driveway (house up top of a steepish drive), brake, point her downhill, put her in D and begin to roll down to the road. Its not a very long drive, maybe 100ft.

Every time, halfway down, my brake pedal grinds and skips under my foot, which I assume is the ABS. I'm just rolling not fast at all, with a light pressure on the brake pedal. No lights come on. I'm sure the ABS isn't required at that point.

Away from that moment the brakes are fine, they work well and have never had to engage the ABS even when I've had to brake with a reasonable force.

Any ideas as to what's causing this?
 

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2011,premium,2.5
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648 Posts
check all lines make sure no bulging brake lines from each disk or drum really well if not that maybe master cylinder...but not 100% on this one best i can do in an early response hope someone will give you better input later on, just check them and fluid also
 

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'03 Outback H6-3.0 Black Granite Pearl, base model with cold weather package and cloth seats.
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1,061 Posts
Is there an ABS self test that runs shortly after starting/moving the car. Might be unlucky timing that this happens when you are using the brakes lightly.
 

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Is there an ABS self test that runs shortly after starting/moving the car. Might be unlucky timing that this happens when you are using the brakes lightly.
Sorry, is that a question or statement? Are you hearing an audible clunk? If so, apparently it's the VDC self-check from what I've read. I was wondering what it was too each time I backed out of the drive way. I was wondering if my new 2012 Subaru Forester XT was falling apart on me just because of a little bump from the driveway. ;)
 

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2000 Lancaster 2.5L
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29 Posts
Discussion Starter #5
Thanks guys, checked the lines they seem fine. Don't think its an ABS self test as i can sit for a bit ticking over then drive away and it still does it.

The noise is not really a clunk, more a grinding noise.

Any other ideas?
 

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'14 3.6R Outback
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2,345 Posts
Brake petal "skipping" sounds like normal operation to me. Sometimes when the abs activates on a car there will also be an thudding or sliding sound, like a squeegee across glass. You did not say what material your drive way was or if the car handles the same all conditions (wet/dry).

When did you last inspect the pads? Grinding is typical when pads are going bad.

The only time I have experienced something like you describe is when I take any of my companies fords into a local parking garage. To get to the loading dock you have to drive into oncoming lanes and drive over the warning bumps (or turtles as some call them, driving by braille for others). Anyway, when I apply the brakes when going down the ramp on those bumps I sometimes loose breaking power for a moment and I get grinding noises and shuddering of the petal. First time that happened scared the crap out me.
 

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2013 Outback 2.5 Premium 6mt
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187 Posts
Any big bumps in your driveway?

There is a route that I take home every single day that includes a bump while slowing to take a right turn (a different height in the road surface from the main road to the secondary road). It sets the ABS off for a moment in my work truck every single time.
 

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03 H6 OBW & 06 WRX Sportwagon
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17,625 Posts
is your driveway gravel?

I think some US cars had a recall to reprogram the sensitivity of the abs due to folks feeling it engage over railroad tracks etc. and other non-emergency conditions. But I think it was older models than yours.


EDIT: I had some details wrong , this is from cars101.com;

8/22/05 2002, 2003 WRX, manual transmission ABS brake performance ecu Satisfaction program 06-35-05R. this is not a recall.
A response to concerns about ABS performance on 2002-03 WRX 5spd of a feeling of a delayed response when ABS is activated during inital braking over bumps, potholes or other low friction road surfaces. With assistance from Subaru, NHTSA conducted over 11,500 tests to investigate this report and while NHTSA and Subaru did not indentify a problem that would require a recall, they did identify a certain ABS performance characteristic that might cause some driver's to identify a delayed response feel during the first second of braking. Following this analysis, Subaru developed an alternative method of calibrating the ABS to address this performance characteristic.No perceptible improvement in overall stopping difference will result. If the driver of an affected vehicle encounters this set of conditions and is uncomfortable, a complimentary ABS with different calibration is available.
This is not mandatory, rather this service is being offered to enhance customer satisfation. Only some owners will experience this ABS characteristic and SoA will contact owners of eligible vehicles by mail through October 2005.
 

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2000 Lancaster 2.5L
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Discussion Starter #10
The driveway is a sealed smooth tarmac surface with one pothole. I definitely miss the pothole every morning but there are a few tiny stones in the area where the problem occurs, I can't imagine they would be enough to activate the abs but i could be wrong, it may be a lot more sensitive than my previous cars.

The brake pads are have got around 7000Kms on them and look fine to me. The problem occurs in both wet/dry.
 

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'14 3.6R Outback
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I'd try sweeping the stones away first. Have you had it happen in other places (out in the world) with a similar grade?

While we are at is there any oil on your drive way (yea, just saw your other thread)?
 

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2000 Lancaster 2.5L
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Discussion Starter #12
I've swept the few stones that were there and it still does it. No oil on the driveway, the car is parked just off the side of it where the oil drips overnight. Had a look around the brakepads for oil but it hasn't made it there, it just collects and drips off a crossmember behind the oil pan.
I guess I'll just live with it seems it's only occurring once a day and normal braking for the rest of the time.
 

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03 H6 OBW & 06 WRX Sportwagon
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there may be a fuse you could pull to disable the ABS. Then, if you still feel the odd behavior - you'd know to pursue something else.

odd
 

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'07 OBXT Ltd. 5EAT, Charcoal Gray; '70 Chevy K10 4X4, 396c.i., lifted; '63 Pontiac Tempest, 326c.i.
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Very odd problem...start with easy solutions like 1 Lucky Texan suggests. If you don't find a solution, go get a brake check and show a technician the problem. *TRY* to emulate the problem. If still no luck and the tech says your brakes check out (make sure he mic'd the rotors and pads and took it for a test drive), then I'd suggest bleeding the brakes. Brakes use hydraulic pressure (from fluid) so my best guess (if every other avenue checked out) is that there could be air or condensation in your lines, causing the hyrdaulic properties to "act funny." Just for giggles, go to your local Schmucks or O'Reilly's and check out the computer to see if you have any codes stored.

If these ideas don't work, walk to work. :)
 

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03 H6 OBW & 06 WRX Sportwagon
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another experiment might be to park somewhere else for a coupla mornings. level or on a different slope, on a different type of surface.

I believe there is a check valve in the hose for the booster, if it is bad, frozen or otherwise compromised, the first one or 2 stops might feel odd. An 'antipodean' driver might experience some freezing moisture in there this time of year?.
 

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There's nothing wrong with your car. It's the ABS self test. You can idle for 25 hours, then drive away and it will still do it. Driving the car activates it, not running duration.
 
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