Unusual rotor wear? [pics]

[AndyTTR]

I've noticed lately that my brake rotors have been showing an unusual pattern on them? I originally thought it was just because the retaining clips were a little out of shape on one caliper, but then i noticed that the rotor on the other side (which is ok as far as i can tell) started showing the same thing.





The brakes are off an ADM ST185 GT-Four, I installed them on my car about 6 months ago. The rotors were brand new from DBA and the pads are Bendix Advance, there's about 60% left in them. I've been told that the rusted area nearest to the hub is normal as the pads sit at the edge of the rotor in these calipers.

Am I right in saying that the shiny area is glazed? I thought slotted rotors were supposed to stop this from happening!

I thought it might be from all the stop-go traffic driving that i do, and a couple of hard stops did get rid of this pattern, but now its come back worse than it was before!

Is this something i should be worried about and try to fix? For the next pad change I was going to go toyota genuine as they come with a new set of retaining clips.

Thanks in advance guys,
Andy

[lunar_c]

Looks pretty normal to me dude .. the colour/shine difference is because the pads don't cover the whole area of the disc .. so the darker patch would be the contact area .. the rusted bit at the bottom and the shiny part on top is uncontacted area .. by my guess anyway.
Not something I'd be worried about - if they're squeeking .. pull the rotors off and get them machined and rough up the pads with some sandpaper (400ish grit wet and dry) ..
Cheers,
Ben

[AndyTTR]

Wouldn't the shiny part be where its in contact more than the darker part? They have started to squeal a bit, which is why i noticed the glazing on the rotors. They shouldn't need machining already should they.. they're only 6 months old and still on the first set of pads (which are only about 40% used)?

[Robbos_Toyotas]

seeing the wearing there it appears all of the disc is being used bar the rusty part. Toyota wouldnt design thos brakes to just run on that inside edge of the rotor, as its the outside area where you get the most grab! you sure the correct pads are in her?

[AndyTTR]

yep, the pads are the same part number as the ones that came off the donor car and the right ones for the ADM ST185 according to the bendix brake catalogue...

Im not really worried about the rusted part, i'm more concerned about the shiney ring around the outside of the rotor. If its wearing out the outer part of the rotor heaps faster than the inner part i'm gonna have a problem!

[Robbos_Toyotas]

hmm, does it steer and brake alright, with no shuddering? Just wondering if the disc is moving and causing more wear on the outside - have you had a look at the pads?

[Negative Boost]

Better bet would be to take it to ABS for a free quote. Then they'll tell you whats wrong and give you a quote with a list of things that need replacing and a BIG asking price. From there you can do it yourself

[PT1]

Id be pulling it all apart and having a look at the pads, and seeing if there are any abnormalities on them which could be causing it. Also need to check the inside edge of the rotor - is it the same? Is this happening to every rotor or just 1?

It's quite interesting in that its a very defined point at which the change occurs.

Long shot totally random possibility - By looking at the pic, its hard to tell, but could the calliper be a bit short? The 2 'arms' that come down over the outside of the rotor dont seem to extend down very far, and if it's a thick rotor it could be just pulling in hard on the top part of the rotor.

[YLD-16L]

I've got the same calipers and mine have even wear across the whole face of the rotor.

What does the inside face of the rotor look like?

I'll have a look at my calipers tonight, looking at yours something doesn't look quite right. What diameter rotor are you using?? You haven't mixed and matched the fixed and sliding parts of the calipers at all have you?

I tend to agree the the comment above that maybe the caliper is not sitting far enough over the disc, but surely this would be plainly obvious? Check your pads and if there is a portion of more that 1mm or so not contacting the disc then that'll be your problem.

[IN 05 NT]

i find it tends to be the heat, leaves marks on th rotors, and machining wont do anything for the colour, its still there after the machine,

the way you caliper and pad is sitting, follow the edge of the rotor and it looks like the pad doesnt sit completely on the rotor....

the rust in the middle is nothing,

just make sure that the pad faces sit completly on the rotor,

[Poggy]

mabye a sticky slide, seems like one side of the pad is pressing harder

[Robbos_Toyotas]

to follow up what was said above, perhaps the calliper is crooked causing more wear on the top half of the rotor - see if the pads are worn at an angle?

[Poggy]

Also if it has just had wheelbearign done, mabye the caliper bracket has been bent when they were pressed in, i've seen it happen?

[AndyTTR]

thanks for the excellent suggestions guys - + rep all round.

I did have an issue with the sliding bushes sticking initially, i thought i had fixed that but maybe they've seized up again? Also that was only one caliper that was sticking, but now both front rotors show the same pattern. Might be time for a complete overhaul ~$190@. :S

yld-16v - if you've got the same brakes, and the whole surface of the rotor is swept then maybe i do have a problem.... But the pads sit almost flush with the outer edge of the rotor, i asked about it a while back in the gt-four thread and the guys said it was normal. Hhhmm.. i'm gonna have to chase that one up! The calipers aren't mixed and matched, the torque plate and piston came from the same car. Perhaps the offset from the hub is different?

I'll definitely pull the pads out and take a look, was planning to change ball joints and tie rod ends this weekend (suddenly an afternoon's work is looking like a whole weekend job!).

The car is going to an exhaust and brake place tomorrow to get the flex pipe replaced, may as well get their opinon on the brakes while its there ey?

[mrshin]

Pull the calipers apart, make sure they are nicely free and greased. Also, do you tend to do a lot of overly gentle braking, or worse, resting the foot on the pedal?