What does this wear mean?

brakes
repair

#1

Hi , had my first car 3 months and every thing was going fine , this afternoon I was leaving the motorway and heard a grinding noise in the front passenger side . There are marks in the disc but the pad looks like it has enough meat on it . What is the problem? The drivers side is fine no noise . There is a bit of a lip on the disc so I think it would need changing soon but it’s not that bad .
Thanks Joe


#2

Either something has gotten between the pad and the rotor and is now imbedded into the pad, or was anyway, or the pad is worn out. New pads have about 12mm of friction material, the absolute min is 1 mm. I’d like to see a picture of the pad, but I suspect you haven’t removed it yet and you are not quite understanding what you are looking at. But again, there could be something that has gotten in there thats not supposed to be there.


#3

If something got between the pad and rotor, that is a sign the caliper is not sliding freely on its pins. Only if a gap opens up between pad and rotor is anything likely to get in there. Cleaning and greasing those pins is an often overlooked aspect of disc brake maintenance.


#4

The “lip” is normal and means nothing.
But you do appear to have either something stuck in there OR… you’re looking at the pad’s backing plate and you don’t have as much there as you think… perhaps a few angstroms left.

Bottom line: you need to get your brakes checked.


#5

If you need brake pads on one side, do the other at the same time. It is not necessary to replace front and back at the same time, but both front pads should be replaced if one side needs it.


#6

Something is chewing it up. Have the brakes by chance been serviced in the recent past?


#7

It’s usually possible for a shop to tell how close you are to needing new brake pads simply by removing the wheel and looking through an inspection slot. That takes very little time so not much expense involved. That’s probably where I’d start.


#8

This car bought used, yes?
Could be cheap rotors with poor metallurgy.
Had this issue once when I was lazy and bought some generic rotors from a popular auto parts chain store.
The metal wasn’t of uniform quality and made ugly stripes on the friction surface.

p.s. OEM pads in this case


#9

Looks like you are experiencing the joys of the 7 dollar set of brake pads. This happens occasionally in normal or expensive pads also.

Like others have said…either something got in between the pad n rotor and is now gouging the rotor…OR there is a foreign mass of metal within the brake pad compound…

Remove the caliper and pads and have a looksie…it should be obvious as to what is causing it…maybe you can pry out the foreign metal and continue on down the road. But it would be wise to check those pads and remedy this before you toast the rotor.

Sometimes these things just grind away till they are no more…but who knows…it could be a defective Brake pad backing plate that has some slag or metal that protrudes into the brake pad compound.

EZ Fix…

Blackbird


#10

I am having a little trouble understanding the photo. It looks to me that the outer pad has slipped almost completely out of place. The car should not be driven like this.


#11

The picture is much more indicative of a normal operating brake caliper and pads and then something being introduced to the pads surface or something in the pad compound that is not supposed to be there…and it is now gouging into the otherwise polished rotor…

This happens kind of often… Remove caliper…pull pads…inspect and remedy.

Blackbird


#12

I’m betting that the OP was looking at the brake pad backing plates and believed himself to have lots of pad left, when if fact the pads were actually as thick as a mosquito’s proboscis. And the hardware was rubbing the rotors.

I hope the OP posts back.


#13

Speaking of a brake pad visual inspection . . .

One of my former colleagues once installed the correct brake pads, but the wrong rotors. The incorrect rotors that he installed were smaller in diameter

A few years later, the customer showed up complaining that the brakes didn’t feel right. This same doofus mechanic pulled a tire and looked through the inspection window, and saw plenty of meat on the brake pads

Then somebody else came up and told him to remove the caliper. It was clear that only the outer edge, closest to the inspection window, had any meat. The rest of the pads were pretty much down to the metal backing plate

Then they got a new set of rotors from the parts department, and held them up to the rotors on the car, to compare them. The new correct rotors were considerably larger in diameter

The mechanic who did the initial brake job got a vicious tongue-lashing. He was told you always have to visually compare new and old parts. Clearly he hadn’t done that the first time around.


#14

It’s surprising during the initial rotor/pad install he didn’t notice a portion of the pad wasn’t sitting on the rotor surface. Maybe that wasn’t visible on that car’s brake design. On the disc brakes I’ve diy’er serviced - Corolla and VW Rabbit – you could see if the pad were laying beyond the edge of the rotor once the wheel was off.


#15

It’s because he wanted to finish quickly and move on the next

He was a fast worker, but he didn’t have an eye for detail


#16

It’s amazing what you can miss if you don’t pay attention.


#17
It's amazing what you can miss if you don't pay attention.

Somebody could publish a book just from all the sagacious sayings here … lol …


#18

Hmmmmmmmmm great idea!


#19

Thats great…What a “Mechanic” might have “Missed” when discussing the method with which you STOP YOUR VEHICLE… This is the area NOT to miss anything. Duh…

Would you rather be able to GO…or Stop… I know where my money is…

Blackbird


#20

I think @the same mountainbike is right and the op is looking at the packing plate instead of the friction material itself.

Replacing the pads and rotors should fix the problem.

Yosemite