Hi, guys,
The stock rotors on my car were warped in the 2nd year of my ownership. Last month, it was time to replace the rear brad pads, so I took the opportunity to replace the four stock rotors with ProStop platinum rotors from PepBoys.

Now, the problem is, the driver side rear rotor has uneven wear. As you can see in the photo, it seems like the pad is pushed to rotor sideways when the brake is engaged. It rained here a few days ago, so you can still see the water spots from the rain. The other three rotors are good.

http://www.flickr.com/photos/alexlizn/11192390555/lightbox/
What do you think the problem could be? This is the first time I have a brake problem like this. I wanted to have some advice from your guys before going back to my mechanic. If it is caliper problem, is it covered by warranty? Currently i have about 46,000 miles on my car.



Thank you as always!
Alex

 

The fact that you replaced the brakes on "the outside" the dealer is going to tell you that its a pad/rotor issue or a labor issue from your mechanic.

I have seen a few fail... Possible.

 

From the dark section on that rotor, I'd suspect the caliper on that side is sticking, or the pad itself is not installed properly. Looks like the pad is only contacting part of the disc itself and is overheating. The only way to know for sure is to remove both pads and inspect them closely. This will not be covered by warranty.

 

something is haywire with the LR pads. do a quick re+re on the pads and give the caliper sliders a good clean and grease. inspect the pads before re-installing to assess uneven wear. if they are worn at a skewed angle, throw on new pads. no big deal!

 

As above. The pads are supposed to be "floating" so any sticking can cause uneven wear. You are supposed to clean the caliper hardware very well when changing pad and good caliper grease on the parts of the pad that contact the caliper hardware.

If I were you, after a reasonable drive, check the rotor temps with an infrared temp gun. If the rotor in question is much hotter, the pad or caliper is sticking.

 

Thank you all for replies!

The dark strip of the rotor is not really 'dark'. It's because of the angle I took the photo. That worn strip is in the same color as the other rotors with normal wear. the silver color of the rotor is the original color from factory.

I do not think the caliper is sticking though because i don't smell any burning smell after my routine trips--both highway and local driving trips in the past two weeks. But I could be wrong. As Mismosh suggested, this could be verified with a infrared temperature gun.

I'll go back to the mechanic who put on my new rotors and pads.

Last note, I came across some tips about brakes saying engaging parking brakes when parked will adjust rear brakes. I've started using parking brakes. Let's see if it will make any difference.

Just Brakes - Frequently Asked Questions on Brake Repair

 

The parking brake thing will have no effect.

There are shoes inside the drum on the rear that are engaged when the parking brake is used. The discs are not used for the parking brake.

 

I didn't know that, interesting.

 

I took your advice, went back to the mechanic. He suspected a faulty brake pad so he replaced the pad and cut the rotor. More than 10 days later, it is still doing the same thing: the pad only touches the inner part of the rotor rim.

I guess it's time for me to look for a new mechanic. After research, I guess the brake piston is in question.

What do you think?

 

Well if you worked on your own car i would tell you to take off your wheel and inspect your caliper and see if you can compress the piston.

 

As much as I like to do it myself, I don't have the stands and tools, plus, life is hectic, really don't have time to do so.

 

Yea thats understandable but like i said if you had a seized piston in your caliper it would cause that, but at the same time your brakes would get really hot and you would smell the pads burning.

I honestly wouldnt be able to provide any other input really...

1-check for a siezed piston
2-check pad travel within the caliper (if its able to slide back and forth freely)
3-check rotor make sure its mounted correctly and is not warped (even though it was cut)

Out of curiousity does your steering wheel shake when driving ?

 

My steering wheel doesn't shake during normal driving, including highway driving. And I don't smell any burning pad after highway driving. Plus, I don't feel any brake drag on the wheel at all.

The above reasons contributed to my conclusion that my car does not have a sticky brake, at least does not have a bad sticky brake.

Again, I've made plan to have my wife take my car to a mechanic recommended by a friend in my area.

Will report back when they find out the root cause.

Thank you for your replies!

 

You are not gonna believe this!

Yesterday, I asked my wife to take my car to a very good mechanic recommended by my friend. My wife put him on the phone with me before he inspected the Left Rear brake. It turned out the Pepboys mechanic put the inner brake pad on the outer position and vice verse.

I didn't see it so do not know exactly how wrong the pads were installed, but i'm gonna follow my friends advice: never trust such important brake job to Pepboys.

Ever since yesterday afternoon, the brake bites correctly :-)

 

The pads are not position specific, either can go inside or outside on either side caliper.