Strange braking issue, 2013 Outback

[smiller]

My wife's 2013 Outback (2.4, 53k miles) has developed a rather strange braking issue. About a week or so ago she noticed that there seemed to be more pedal travel than usual. She believes the problem came on either suddenly or over a short period of time. The symptom is that there is indeed more pedal travel than in the past, but at the end of the additional travel braking action seems normal. Short stabs of the pedal at walking speeds are normal, but at any speed above about 10 mph the additional travel becomes evident. Brake boost and pedal effort are normal, and as you depress the pedal you can feel a light resistance when the booster activates and this is where braking action has begun in the past, but now there is some strange additional travel before braking action begins.

Brake fluid level is normal, and a visual inspection of the system including calipers reveals nothing unusual (no signs of any leakage or seeps.) Brake pads are somewhat worn but not at wear limits (original pads, evenly worn, commensurate with the mileage on the vehicle.) I bled the system at each caliper, nothing unusual noticed and no improvement. I also generated some ABS activations on a dirt road, operation seemed normal, no change in problem. Also there are no fault codes present associated with the braking system (using the Subaru-specific program on an Autel scanner.)

Not sure where to go from here since there is no obvious problem yet there is definitely a different feel, although it might not be obvious to someone not familiar with the vehicle. From an old-school perspective the feel might suggest a leaky master cylinder, but that seems kind of doubtful on such a relatively low-miles vehicle. I could change the pads, calipers, etc. but that seems like throwing parts at the problem because there is really zero evidence that they are a factor.

Has anyone run into this before?

TIA from the new guy...

 

[AMLOR]

My wife's 2013 Outback (2.4, 53k miles) has developed a rather strange braking issue. About a week or so ago she noticed that there seemed to be more pedal travel than usual. She believes the problem came on either suddenly or over a short period of time. The symptom is that there is indeed more pedal travel than in the past, but at the end of the additional travel braking action seems normal. Short stabs of the pedal at walking speeds are normal, but at any speed above about 10 mph the additional travel becomes evident. Brake boost and pedal effort are normal, and as you depress the pedal you can feel a light resistance when the booster activates and this is where braking action has begun in the past, but now there is some strange additional travel before braking action begins.

Brake fluid level is normal, and a visual inspection of the system including calipers reveals nothing unusual (no signs of any leakage or seeps.) Brake pads are somewhat worn but not at wear limits (original pads, evenly worn, commensurate with the mileage on the vehicle.) I bled the system at each caliper, nothing unusual noticed and no improvement. I also generated some ABS activations on a dirt road, operation seemed normal, no change in problem. Also there are no fault codes present associated with the braking system (using the Subaru-specific program on an Autel scanner.)

Not sure where to go from here since there is no obvious problem yet there is definitely a different feel, although it might not be obvious to someone not familiar with the vehicle. From an old-school perspective the feel might suggest a leaky master cylinder, but that seems kind of doubtful on such a relatively low-miles vehicle. I could change the pads, calipers, etc. but that seems like throwing parts at the problem because there is really zero evidence that they are a factor.

Has anyone run into this before?

TIA from the new guy...

Sounds like you did a pretty good test on the system...curious that the "problem" still exists.
So I am going to assume that the car has a standard vacuum brake booster and NOT a hydro-boost system.
It is possible, however unlikely given the low mileage, that the vacuum booster has a small leak in the diaphragm.
The Stealership or a good independent mechanic may be able to confirm that the booster is leaking.
good luck
AMLOR

 

[smiller]

Thanks for the response. Since the rear pads are near wear limits and the front getting close I am going to replace them since I will need to soon in any event. I am also going to do a pressure bleed to be certain I have no trapped air anywhere, and also check the rubber brake hoses under pressure to ensure no bulging. If none of that is successful then there's not much left except an exotic problem with the booster, ABS modulator, etc. and I may be forced to have a dealer look at it

 

[AMLOR]

Thanks for the response. Since the rear pads are near wear limits and the front getting close I am going to replace them since I will need to soon in any event. I am also going to do a pressure bleed to be certain I have no trapped air anywhere, and also check the rubber brake hoses under pressure to ensure no bulging. If none of that is successful then there's not much left except an exotic problem with the booster, ABS modulator, etc. and I may be forced to have a dealer look at it

I would agree with your analysis. Make sure to use a Top Tier brake fluid.
Motul RBF 600 is a great choice. Has a dry boiling point of 594 degrees and a wet point of 421. That exceeds virtually all DOT4 brake fluids. I have used it for years in my 4Runner we use for towing our Airstream camper. no fade, ever.
Good luck
AMLOR

 

[Kate]

My wife's 2013 Outback (2.4, 53k miles) has developed a rather strange braking issue. About a week or so ago she noticed that there seemed to be more pedal travel than usual. She believes the problem came on either suddenly or over a short period of time. The symptom is that there is indeed more pedal travel than in the past, but at the end of the additional travel braking action seems normal. Short stabs of the pedal at walking speeds are normal, but at any speed above about 10 mph the additional travel becomes evident. Brake boost and pedal effort are normal, and as you depress the pedal you can feel a light resistance when the booster activates and this is where braking action has begun in the past, but now there is some strange additional travel before braking action begins.

Brake fluid level is normal, and a visual inspection of the system including calipers reveals nothing unusual (no signs of any leakage or seeps.) Brake pads are somewhat worn but not at wear limits (original pads, evenly worn, commensurate with the mileage on the vehicle.) I bled the system at each caliper, nothing unusual noticed and no improvement. I also generated some ABS activations on a dirt road, operation seemed normal, no change in problem. Also there are no fault codes present associated with the braking system (using the Subaru-specific program on an Autel scanner.)

Not sure where to go from here since there is no obvious problem yet there is definitely a different feel, although it might not be obvious to someone not familiar with the vehicle. From an old-school perspective the feel might suggest a leaky master cylinder, but that seems kind of doubtful on such a relatively low-miles vehicle. I could change the pads, calipers, etc. but that seems like throwing parts at the problem because there is really zero evidence that they are a factor.

Has anyone run into this before?

TIA from the new guy...

 

[Kate]

My 2017 outback had the same issue, and still does. Every time I bring my car in for routine service I have mentioned that my brakes feel”soft” in that when I apply my foot to the brakes there seems to be more empty space underneath the brake if that makes any sense. Eventually the brake reaches solid space and the vehicle will stop but I have had to learn to slam my brakes on in order to make the car stop when I want to. When I report this to Subaru at service I am told the same story that everybody gets told: we are unable to duplicate customers. Which is a bunch of Malarky but I thought you would like to know.