|08-08-2014 09:55 PM|
PratoN - that band happens fairly often on old/high mile brakes, If you hadn't mentioned the mileage I would have wondered about the picture as it usually takes more time to get that "old".
Replacement of the rotors/pads is the only fix, make sure to clean/lube slider surfaces so the new ones work well.
If you look close at those rotors, you'll notice the rusty area is lower than the rest of the surface. This is an odd wear pattern that develops over time, starting small & expanding before you notice it.
Pads normally "clean" off rust that occurs any time the car is parked - worse when they get damp/salty. Rust is more abrasive to the pads than a smooth surface, sometimes a combination of that and/or slightly less pressure toward the edge results in an area that doesn't get scrubbed smooth. Pads can hang a little where they slide on their supports so less pressure applied at the edge, rust can scrub away more pad material where it's the worst so less pressure is applied there.
Whatever the exact sequence, once it doesn't get scrubbed perfectly clean at the next use it rusts MORE there, causing more pad damage so there's less pressure to clean the rust off.
Now, as soon as there's a tiny section that's not burnished smooth by the pad - that section rusts faster than the surrounding area that's polished and it becomes a low spot on the rotor as the iron disappears. It's a self reinforcing sequence - even if the pads aren't hanging up in their holder, the rusty area flakes away quicker than the smooth surface & the pad can't clean it up because when it DOES come in contact it's chewed up by the hard abrasive rusty section, never getting enough pressure there to clean it up.
Regular use often prevents this, but even that isn't a guarantee. Any rust spot can start the process by chewing at the pad and you end up with that nasty rusted out section of the rotor. It typically gets bad at an edge of the rotor due to uneven pressure that didn't scrub it clean at some point - center of the rotor gets the most pressure & usually stays the cleanest.
Worst I ever had was when I had to park the P/U near a salt water inlet for a week at a time - twice in a row. BAD rust each time I got it rolling again (break 'em loose to roll bad) and the pad locations were the worst. Pulsations from the rust at the pad locations and that started a sequence resulting in worse stripes than you pictured by the time I finally just replaced them. Only chewed smooth enough in the centers to be "passable" braking until they wore out completely.
|08-08-2014 05:44 PM|
I learned the lesson about occasionally using the parking brake (which I never did because I always parked the car on a flat surface) the hard way when I had my 1984 Tempo. One year, took the car in for the annual state inspection - this was back when gas stations allowed you to pull the car into the bay yourself and mechanics were less than diligent about verifying that everything on the list was checked (as a result, I hadn't had the parking brake checked for several state inspections prior to this).
After going through lights, horn, windshield wipers and washer, the mechanic had me step on the brakes, set the parking brake, put the car into gear, and then release the brakes. As soon as I released the brakes, the car started to roll forward. As a result, this incident was the only time in 27 years of car ownership that I ever failed a state inspection.
But, lesson learned. Besides occasional use during normal parking, double checking that the parking brake works has been part of my "pre flight" check before I go in for a state nspection ever since then.
|08-08-2014 02:19 PM|
I had the same weird grooves on my rear rotors and finally replaced them a few thousand miles ago since my pads were pretty low too (I'm already at 92k miles) and this is what the rear rotors looked like:
But I was the one who had the rough/clicking bearings in the back that I was convinced caused the rear rotor grooves and the irregular wear on my rear tires. I was in Seattle and I saw a BMW with grooved rotors like this and I immediately checked the inside of the rear tires and sure enough they had that weird heel-and-toe wear on the innermost tread. Not saying it's definitely the issue, but it's a good place to starting looking imo.
My front rotors have a different issue where the outermost ring of the rotor is glazed or rusty looking? My coworker's early 2012 Focus has the same grooves in the rear rotors and the same glaze band in the front rotors.
I was considering resurfacing them myself but it's almost not worth it with the coupons that Advance Auto just gives away. I just wonder what caused this to happen?
|05-20-2014 01:50 PM|
|gdcwatt||Just an update... Now with 35,000 miles and 3 yrs of use, the original "oddly wearing" brakes are still working great. Every once in a while I get to drive the car, and occasionally go through a bit of a rebedding process.|
|05-12-2014 02:12 PM|
Have seen a few reporting more "grooving" than they feel is normal, that tends to result from more aggressive pad materials that give better braking performance, particularly in the wet.
The only contributing mechanical issue I've seen reported is rear wheel bearings, noise when not braking is the identifying symptom most often noted.
Grooving per se isn't an issue, pads & rotors are more often replaced as a set these days - for this reason.
Rear pads & rotors have less material than the fronts, "normal" braking wears fronts much faster than the rears & the idea is to even out wear at each end.
Not a large number of posts commenting on brake wear, more with rear wearing first but I've seen a couple reporting front wear they weren't happy with. Hwy. use & light braking might factor into the rears wearing faster. Wonder both how worn the pads really were (vs. replaced for "grooving") and how many miles you got before replacement was recommended.
Can't second guess at a distance, in a few cases replacement was "sold" by pointing out grooving before pads were worn enough to require it. Could just as easily have been "due" for replacement.
Recommendations usually err on the side of caution, anything likely to need service before the next oil change service is recommended - and with that interval stretching up to a possible 10,000 miles on the current cars "half worn" is often the standard.
P.S. - saw a post today from an owner with a Manual trans., 104,000 on the original brakes. As they say, "your results may vary".
|05-12-2014 12:27 PM|
|Evil Smirk||unfortunately i seem to have the same problem. my 2012 focus has a rear brakes issue. after getting my summer tires put on, the dealer said i needed a complete rear brake job (pads and rotors). i found that odd that i needed to replace the rears yet the fronts are still good. i asked the the technician if there was a mechanical issue or something because i never had to replace rears before fronts before in any vehicle i owned. he said no that everything looks good just that the pads/rotors are worn out and grooved badly. most of my driving is highway and i really don't understand why this is and feel this should be a waranty issue considering its the original parts. i tried to call customer service but they don't know anything and said they cant do anything|
|03-03-2013 02:28 PM|
The rears seem to show greater wear, and my bedding the rears involves driving backwards and several hard stops; the autotrans/computer seems to limit how fast I can drive in reverse.
Still, after 20,000 miles, the brakes still work great. But I was actually found this thread while researching replacements, for when it's time for a change...and while that may be in a while, I will continue to watch my rotors, rebed, and sand twice a year.
|03-31-2012 06:15 PM|
|03-30-2012 11:03 PM|
P.S. - The last time I saw a REAR brake that someone wanted warrantied, it was on a Motorcycle. And the owner wore out both the rear tire AND the rear brake (pads & rotor) by the time he brought it back for it's 600 mile check up! You can probably guess how THAT happened... (grin)
(Thought you could use a chuckle...)
And if the Dealer needed to order parts, they found SOMETHING wrong....
|03-30-2012 10:57 PM|
Well, you SHOULD use it occasionally, or someday when you need it it won't work!
And notice the OTHER common culprit, a mechanical issue causing it to drag....
BOTH are more common than defective pads or rotors.... Not that it COULDN'T happen, I just haven't seen a case yet....
( I always like to hear a reason for a failure, even if it's fixed under warranty...)
|This thread has more than 10 replies. Click here to review the whole thread.|