[Big Ro]

EDIT: The crunching/grinding noise is from the front, where there are new pads and rotors.

2005 Outback 2.5i


I'm posting after searching long and hard to no avail for any threads that might help.

Fairly often, there is a quite noticeable grinding/crunching noise while braking. It's loud, and is also intermittent. Sometimes braking is as smooth as butter.

Here's what I know:

• Front rotors and brake pads were replaced about a month-and-a-half ago (by me).

• Rear rotors and brakes have not been replaced in a long while.

• It only occurs at slower speeds (30 mph and under-ish).

• I can feel the vibration through the brake pedal.

• It lasts for the duration of the braking. As long as I am braking, it crunches. When I let my foot off the brake just a little to inch forward in traffic, it crunches.

• Sometimes after braking hard (someone pulls out in front of me) my brake warning light on the dash comes on and stays on for a while. It eventually turns back off.

• I brought it to a mechanic a couple of days ago who inspected the brakes, said they didn't see anything obviously wrong.

Here's what I don't know:

• What the freak is going on.

Any tips?

 

[1 Lucky Texan]

not much help from except to offer that the brake light may only be the float in the reservoir - if fluid is marginally low, sloshing fluid and sometimes even parking on a slant or fluid contraction in cool mornings will cause it to come on.

I'd inspect wheel bearings.

 

[theoak]

Does the vehicle have anti-lock brakes? Is your anti-lock braking system kicking in? If folks are not familiar with ABS it can throw you off at first.

 

[DavidPeab]

Did you bed the brakes - mate the pads to the rotors? Do a series of hard near stops from 60 mph down to a slow roll (not completely stopping) braking hard to heat up the pads and "mate" them by coating the rotors from the pads. Also, hit the whole area with brake cleaner - before the bedding procedure - in order to get any flakes of rust or dirt that my have come off of the dust cover plates. Also, make sure the dust covers are not touching the rotors and that there are no pebbles or such between the rotor and the dust covers.

 

[rsrocket1]

By all means check your rear brakes and rotors. I just replaced the original rear pads on my 08 which were worn down almost to the lining at 130,000. You should also check the front pads. The one time I tried to bed the pads, the caliper pins bound up and wore the front pads down to nothing in < 5,000 miles. Fortunately they were from Autozone and they exchanged them for free. After lubing the pins, the problem never returned. My front pads typically last 2-3 years except for that one time.

 

[idosubaru]

Why have you not noted whether it is front/back or left/right?

Debris stuck in the dust shield?

Slide pin pushings do this - the bushings will swell and partially seize the sliding pin in the bore. At first it's mild and the conditions worsen over time. this will cause intermittent noises as the caliper tries to compress "at a very slight angle" - with one pin sliding smoothly and the other partially binding (there's only a bushing on one pin).

over time it gets worse as the brake pad wears unevenly and the bushing condition gets worse and eventually the caliper will basically seize in place at that one pin and want to "rock" on it since the other pin doens't have a bushing and slides smoothly.

An inferior grease on the bushigns will cause them to swell - so if you used regular caliper grease on the slide pin bushings when you did the job, this could be the case.

 

[Big Ro]

Grinding coming from the front

The crunching/grinding noise is from the front, where there are new pads and rotors. This is what is puzzling.

 

[1 Lucky Texan]

there have been folks finding pads with back/mount plates that needed grinding or filing to 'float' properly without binding.

or even sold incorrect parts