Three month ago, I changed out my OEM brake pads for some Endless SuperStreet Sport-S pads. After changing them, I bedded them in (twice actually) and have had no problems with them since that time. They stopped great - I even ran them on a HPDE with no problems at all.

Yesterday morning on the way to work, somebody pulled over in my lane forcing me to brake hard. To my shock, I almost couldn't stop the car.

This afternoon I was on an isolated highway and decided to test my brakes and sure enough, it was like they had no stopping power. I repeated three 70 mph to 20 mph hard braking stops to heat them up and they seemed to get their grip back.

Those Endless pads are streetable, so they shouldn't and haven't required a warmup. I'm wondering if it's just some kind of buildup on the rotors or on the pad face. I haven't been braking hard very much on the street and the last couple of autocrosses have been in the rain so no hard braking there either. The fact that the grip came back after a couple hard stops leads me to think it's either heating them up or it cleaned the surface of the pads/rotors.


Any ideas of what might be going on or what I can check or test?

 

Well, that's odd. If I was to guess, running in hpde might have caused a little melting or what not to disrupt the clean even contact surface. After a while, it'll go away. But a slotted rotor shaves the surface of the pad in case that happens at a track and it'll ensures an even contact patch every time.

 

I took the car out a little while ago after the brakes had a chance to cool. They seem to be gripping better now. I'm probably going to take a look at the pads tomorrow to see if there's any glazing or something like that going on.