So now that the temps have dropped here, I'm reminded of this issue and wanted to get some feedback and education from the Family.
Background: When I bought Jersey Graphite last year, she came with BMW Perf rotors and ceramic pads (brand unknown). I've been very happy with the performance of the pads and lack of brake dust. There has only been one little issue that makes my applehole pucker on occasion...
The Issue: So last December I'm driving on the highway in the rain for about 30 minutes heading home. I line up for my exit ramp and get ready to enjoy rolling through the nice, tight 270 degree corner. I get to my braking spot and go to bleed off some speed before I take her in. I step on the brake and get.... nothing. I get the usual resistance from the pedal, but zero braking. I feel the 'ol adrenaline dump as my brain visualizes what my precious ZHP is going to look like after I end up scrubbing 30 mph of speed off with a guardrail. Then, after what felt like an eternity (but in reality was about 1 to 1.5 seconds), normal braking action returned and I was able to roll the corner with no drama.
Upon returning home I check a few things-- brake pads are fine, fluid is full, rotors look good. Hmmm.
I drive for the next 1,000+ miles with no issues. Then, about two months later, it happens again. Same thing: highway driving, rain, 1.5 seconds before the brakes start grabbing.
So the next time I'm driving in the rain a few months later-- I'm ready. I approach my exit and get on the brakes earlier than normal. And of course-- I get immediate braking with no delay-- wtf?
The Puzzle Solved: I happen to mention this little conundrum to Marc (zhpnsnv) while helping him put in his performance intake. Marc informs me that he has experienced this as well, but only when it's colder than about 55 degrees in the rain. Something to do with the heat not staying in the pads when it's colder. This jives with my episodes as I realize the only difference between the times when I have immediate braking vs delayed braking is warm weather instead of cold. This also makes sense because my brake response is fine in the cold/rain when I'm driving around town. It's only when I've been driving without using the brakes for 20 min or more that it happens.
My Question: So, is this normal in everyone's experience for ceramic pads? Do some brands exhibit this condition worse than others? Is there anything I can do to mitigate this?
I love my brakes and lack of dust, but I'm not excited to be back to the time of year when I don't have brakes for 1.5 seconds every time it's raining and I drive on a highway for 30 minutes. I can plan for early braking for an exit, but if I have to get on the brakes in a hurry for accident avoidance or anything like that, I'm going to be whistling the Jeopardy theme for the first 1.5 seconds...
Sorry for the long read. Thanks for hanging in.
Comments, experience, and suggestions welcome.