uneven brake pad wear

Aug 09, 2007 9 Replies

Hey, I just changed the front brake pads on my '97 Legacy Outback 2.5L with



146,000+ miles. I bought the car a year and a half ago and the brakes have been squealing for about a year. I heard metal on metal grinding the other day and decided to stop driving until I bought pads from the dealer and replaced them. I got the new ones on and the squeak is gone.

Here are two pictures of the pads I removed, the front left pads are on the left and the front right pads are on the right. The furthest pad on the right is the outside pad of the passenger side.



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Should I worry about this uneven wear? My rotors seem fine, though there are some minor grooves from the pad being almost completely worn down. I used a drill and sandpaper attachment to grind them down as much as I could. I suppose it's possible that someone replaced just the driver's side pads before I got the vehicle, but after a year it doesn't seem like the replaced pads would look that thick. Although, writing that last sentence reminds me that the guy I bought the vehicle from said he had replaced all the pads right before he sold it to me...



On that same passenger tire, I noticed that one of the gaskets from the piston (I think. The pistons are the cylinders you depress to rotate the assembly back together...right?) looked like it had slipped out a little. I would have grabbed a picture, but my hands were filthy. It wasn't seated completely like any of the other ones, anyway. Is this part of the problem?



When driving today, it sounded like the rear brake might have been part of the squealing. I may pop the back tires off tomorrow to see if the rear pads are in terrible shape as well.



Thanks for any tips.



I'd guess the previous owner or his/her mechanic only changed the left pads last time.

I'd inspect the new ones 10,000 miles from now and see if they are wearing evenly. If not, then I'd wand to find the cause.

I agree it could be that only one side was replaced.

In any case I would:

- check the shims to make sure that the pads fit snugly and are not lose to rub against the disk when no pressure is applied.

- replace the brake fluid and make sure that the piston goes easily into the caliper.

- Make sure that the caliper slides easily on the tow posts that hold it to the pad holder bracket.

- Make sure that the pads have the shims that cover the surfaces that go against the caliper and piston

The seal you talk about is called a dust guard, the piston is the piston and the body where the piston goes is called the caliper. If dust/moisture etc., enter the piston/caliper assembly, the piston could stick, thus not freeing the pads completely when the pedal is released.

Good luck!

Jim Stewart wrote:

Was this vehicle used for postal or other curbside delivery? Sometimes that will cause very uneven wear. Or perhaps the caliper was sticking on the slides?

Carl

Carl, I'm intrigued in knowing what the reasoning behind your thought is. Initially, I thought that what you said didn't make sense, but I realized that you may know something that I don't. I always enjoy learning.

Thomas, I'll come and help you. Email me privately for a good time.

Well, I once heard a letter carrier that used his own vehicle (rural route I guess?) call into a 'well known automotive radio show' to ask if it was OK to just change pads/shoes on one side of his vehicle due to excessively uneven wear. Seems the tires that are in the gutter slide a lot on gravel, wet leaves, snow,??? And the tires in the street do the majority of the deceleration. But the OP's car would have to be British/something I think for that to be the problem so I vote for either a sticking caliper or, some type of damage/premature wear on the other wheel requiring a new set of pads.

Carl

Most likely the pads were just hanging up on some rust on one side. This happened to my '98.

Now I take the pads out every year or two, remove the clips and shims, clean off all rust on the pads and calipers with a file, re-grease the sliding surfaces, and put everything back together making sure the pads move freely. This does not take long. I live an area with road salt........

Peter

In alt.autos.subaru, (Carl 1 Lucky Texan) wrote in ::

Just stumbled across this: USPS apparently use right-hand-drive Subarus for some delivery routes, as the driver can lean out and stick items into postboxes without leaving his vehicle some of the time, and can exit on the kerb side at any time. Subaru in the UK have used this to their advantage at times, importing RHD US-made ones to the UK at knockdown prices.

Yeah, pretty sure some guys over at

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have mentioned owning the Postal version of wagons. maybe someone reading here as well?

Carl

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