What could have caused the pad to damage like this?

[bavarian06]

I'm running AP Racing Pro 5000 caliper and the pads are Ferodo DS1.11. The vehicle is E90 M3. The pictures are after Buttonwillow. I thought my brakes were fading due to pad compound or heat but I would have never guessed it was because of this. Any idea what could have caused this?

[roastbeef]

hard to say for sure, but it could be from dropping them, rapid cooling like a splash of water, or a manufacturing defect.

[Estoril Blue]

The friction material doesn't look well-bonded - either in the severe case - or in the other pads which are also degrading in an unusual way.

I wouldn't use that compound again.

[DrFerry]

Originally Posted by roastbeef

hard to say for sure, but it could be from dropping them, rapid cooling like a splash of water, or a manufacturing defect.

bavarian06 This ^. I was going to say the same thing. I've seen pad material, when dropped from only waist high onto a concrete floor, completely break off and separate from the metal pad backing material. It's possible such a thing could happen even during shipping as well as during installation. Whatever the case you, should alert AP Racing and send them the photos IMO just in case there has been an issue with manufacturing.
FYI jritt@essex

[former 240 s14]

If you didn't bed them in properly getting them up to temp and letting them cool entirely this could potentially happen I think. Do you know if you bedded them in for sure? Most companies have a procedure specific for their pads.

Rubin

[bavarian06]

Thanks for the responses. I was experiencing a sudden drop off in performance when I was tracking at Buttonwillow (track in Socal). I thought it was the compound not providing enough bite for the weight of the car. I would have never imagined it was because of this. Basically one half of the pad shattered. For reference, the ambient temperature that day was 70F at best. I did not splash water on the brakes and obviously did not drop the pad. I was horrified to find it in this condition when I removed them. Good thing I did too! Imagine if I did another track day on these. I'm swapped them out for DS3.12.

I did follow Ferodo bedding procedure the best I could. I also went on a few canyon runs to put down a few layers of pad material onto the rotors. They felt fine until it didn't.

The lesson, check your pads often even if you have plenty of pad left.

[roastbeef]

the only time i've had pads chunk like that were ferodo pads that i let get down to backing plate thickness. they tend to chunk at the end of their lives and separate from the backing plate. sucky part is you don't know it until you go for the brakes and have a very long pedal and a lot less braking power.
cobalt pads have like a knurled backing plate and i've never had them chunk.
on the subject of dropping pads- i try not to drop them at all. even a drop from a caliper height seems like too high.

[bavarian06]

I did Buttonwillow yesterday and the brakes performed a lot better. Zero fade and my fastest lap was at the end of the day. I removed the DS3.12 to inspect them to make sure they didn't break apart. They are intact but I can see where the larger piston exerted more force (AP caliper has pistons of varying sizes). See if you can tell which pad edge is where the larger piston is. AP calipers are not kind to Ferodo pads.

I reached out to Essex but they have been slow to respond. Is this common?