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severe braking vibrations and soft pedal on 05 Impreza Outback Sport

So, the car is just over three years old with about 20K on it (yes, I don't drive that much).

While there has always been some vibration when braking (presumably due to the antilock brakes grabbing and releasing), I just noticed that even if I brake a little bit, say to slow down 5 mph from around 55 or 60mph, there is severe vibration that I'm even feeling in the steering. Could this have anything to do w. my pads starting to get close to the replace point or tire rotation (just done)/etc? Normal ride/coast feels just fine, and at lower speeds, not nearly (if any) vibration -- car also seems well aligned and stays straight when braking/accelerating/letting go of wheel).

I think this is not normal, but need to know what to tell them since they will probably tell me everything is within spec and it's normal for this age of pads/etc.

Since the NYS annual inspection about two years ago, when I picked up the car after that inspection, I discovered that I suddenly had to press the brake pedal down much further before the brakes would physically engage (the brake light still lights as soon as the pedal is barely tapped) whereas before that inspection, the brakes were quite tight (I did not have to touch the pedal much at all for the brakes to slow the car). Went back to the dealer and told them, they checked, told me that the distance to pressing the pedal was normal, everything was within spec, and that if I pumped the brakes a little it would get better (which it does, but it always goes back down to that point after a while and I've occassionally felt the pedal sink down while stopped back to that point). It's never gone below having to press the brakes more than that.

So, they claim everything is right... but clearly something changed during that one inspection (which included checking the brakes).

Any thoughts on either or both of these issues w. things I can tell them to check?

Thanks!

Reply to
Dave Botsch
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It sounds as if your rotors (discs) need to be resurfaced. Since you drive so lil, i think the rotors may get rusty between uses and cause all sorts of issues. At 20K i doubt you need new pads.

The vibration when slowing down the 5 mph you say, could be warped rotors, uneven surface on them, alignment (doubt it) or suspension wear (really doubt it).

Warped discs or air in the brakes hydraulic system may cause the pedal to feel soft.

In NY, do you have the car inspected at a mech. shop, right? Was it the dealer that you refer to? Tampering? Do they have the equipment to test all wheel drive vehicles? Was the awd disconnected during the test?

Good luck!

Dave Botsch wrote:

Reply to
AS

No.

-- not specifically to poster --

HEY GUYS. WITH MODERN CARS, YOU REALLY REALLY SHOULD LEARN WHAT ANTI-LOCK BREAKS ENGAGING FEELS LIKE. GET OUT FIND SOME GRAVEL IN A SAFE AREA, GET SOME SPEED AND STOMP ON THE BREAKS.

THIS LITTLE BIT OF EDUCATION CAN SAVE YOU PANIC WHEN IT HAPPENS IN REAL LIFE, WHEN YOU SHOULD BE THINKING ABOUT GETTING OUT OF WHATEVER SITUATION YOU ARE IN.

-- end not specifically to poster --

Knowing what ABS does is as fundamental to driving a modern car as locking it in the parking lot is.

I just noticed that even if I

I'd suspect rotors.

Reply to
.._..

On Tue, 28 Aug 2007 23:19:42 -0400, against all advice, something compelled Dave Botsch , to say:

There is a good chance that your caliper has frozen. It's supposed to be able to float over the disk, and if it quits doing that, you'll get the symptom you describe. That, or a warped rotor, or both.

OBTW, anti lock breaks don't kick in under normal driving conditions, unless you normally go into panic stops.

Reply to
Steve Daniels

With respect to rustiness, we do have the salt on the roads up here in the winter. And, the car is stored outside, unfortunately.

I would say it seems like it's somewhat worse since the last NYS insepction (which was combined with a regular subaru maintenance interval).

I only take my car to the local Subaru dealer - for any repairs, subaru maint. intervals, and for New York state inspections.

The pads are getting down there... I would have to look, but I believe they are now under 50%.

Are the rotors something that can be easily tested? The stuck caliper mentioned by a previous poster?

and any thoughts on the "soft" break pedal?

thanks.

Reply to
Dave Botsch

Hi.

While I appreciate the suggestion, the brakes do feel significantly different as compared to braking at high speeds versus low speeds. And while I do, every year, take the car to a parking lot to remind myself of how it responds and skids to braking at low speeds (say 20 mph) on snow and ice, I'm not about to try that test on any surface of slamming on the brakes at 60mph.

Yes, even normal st>

Reply to
Dave Botsch

thanks for the response!

Let me ask the following:

  1. would any of these symptoms be related at all to what I described as the brake pedal softening (having to push it down further) -- as if when they took it apart for that first inspection it never got put back together quite right?
  2. Presumably, there's some adjustment that tells the antilock brakes when they need to do their thing -- could that be off?
  3. Warped rotor/stuck caliper - can one lead to the other, and is it easy for the dealer to test for these?

Thanks!

Reply to
Dave Botsch

On Wed, 29 Aug 2007 18:53:45 -0400, against all advice, something compelled Dave Botsch , to say:

No, but it's certainly a serious issue in its own right.

Got me. But if you drive on salted roads, the chances of your calipers being frozen are a lot higher than your ABS going on the fritz.

It would be unusual for a rotor to be warped at 20K miles, but the salt may have done Bad Things to your brakes. It is easy for the dealer to check. All he needs to do is test the rotor for runout, and while the rotor is off for that test, to see if the caliper can be slid back and forth a bit.

Were I you, I'd get a complete brake inspection and fix whatever is wrong. If you motor quits, you can't go. If your brakes quit, you can't stop. Guess which condition will get you into the most trouble?

Reply to
Steve Daniels

Good post except rotors can have uneven pad material deposited in the first mile. Whether someone at the dealership is responsible - who knows? Assuming you are not a do-it-yourselfer, I'd suggest taking your concerns and your car to another dealership or GOOD independent mechanic/brake shop.

A single hard stop - followed by holding the car stationary for a few minutes with the brake pedal, CAN create what most folks call 'warped' rotors. check;

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Carl

Reply to
Carl 1 Lucky Texan

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