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Dumb question #99 - I've just noticed that I have more brake pad material transfer to the disc from about the outer 50% of the pad with little transfer noticable from the inner 50% of the pad. Is this normal or does it indicate a problem with the pad installation or calipers? (I recently had Dixcel SD rotors and M pads fitted at the front of the car)

Anyone have any ideas on this? Dropped the car in for a service this morning and the only suggestions the mechanic could offer were that maybe the disc design or the fact that the pads are wider on the outer half cause greater heat (hence resistance) in that area, or the caliper design isn't suited to this pad.

SegR wrote:Dumb question #99 - I've just noticed that I have more brake pad material transfer to the disc from about the outer 50% of the pad with little transfer noticable from the inner 50% of the pad.

I'm still confused. When you said the outer 50% of the pad and the inner 50% of the pad, do you mean a single brake pad?

What calipers do you have on there now?

I mean if you were to draw an imaginary line across the pad lengthways, the inner half is the low half closer to the centre of the disc and the outer half is closer to the edge of the disc or the tyre. So basically the circle of deposits that the pad 'draws' on the disc as it rotates is only half as fat as I expected.

Stock 3.0r calipers.

Hmm ... a picture might help.
It might also be not properly bedded pads/disc as well.

You mentioned new rotors and pads, they done at the same time?

Yeah did the pads and rotors at the same time. I think from memory phat said no bedding in needed for those pads, just no hard braking for a while. Knowing my luck the mechanic probably gave them 10 hard stops after installing them. HA.

Will see if I can get a photo up.

Makes sense now.

This may sound like a dumb question, but are the pads and the disc parallel? Maybe the pressure of the calipers on the pads on the inner portion are not applying pressure correctly (leak/jammed/etc)?

That's exactly how it seems champ but they look parallel and I also had them checked last service. Will see if I have time to get pics up tonight.

photo showing heavier transfer toward outer edge:

Is this on one wheel or a few (all)?

If only on this wheel, maybe swap the pads to see if its this pad or the calipers thats causing it.

It's the same on both fronts which were installed at the same time (pads & rotors)

From the honing marks on the rotor, I would suggest you check to see if the pistons are seated correctly and run them in are little more.

You might just have are hard spot in the brake media.

This sometimes occurs due to the type of caliper style we have (floating head type), as most of the clamping force is at the top.

Could be your new rotors, new pads and or the way you brake apply.

Unfortunately you won't pin point on line so best bet is to seek advise from a reputable brake specialist like Competition Friction/Vsport/Racebrakes & or talk to Michael (PHAT GT).

Thanks for the feedback guys. Talking to Phat (I know he's busy so thought I'd canvass opinions here first) is on the list as is taking her to a brake specialist if necessary.

Probably don't have the time or skill to check the pistons myself.

Phat says give them more time to bed in, so that I shall do.