[MLB]

Last year I put on all 4 new Zimmerman rotors, stock type, and new porter field r4s pads. Bedded in according to stop tech method and others tips here on the forum. All was well. Winter stored in enclosed trailer, which was inside a concrete floor building, no heat. Got car out, drove it a bit in totally dry conditions. Left on concrete floor the past few weeks. Spring thaw temp cycles probably caused some condensation while it sat til this past weekend. Horrible pulsing of brakes with obvious pad-shaped discoloration on rotors; not orange rusty, but more blue-ish black.

Maybe I could remove and sand the rotor surfaces to restore?

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[flash]

blueish/black indicates overheating.  this can happen, especially with pads and rotors with only a few miles on them.  you may be able to correct that by scuffing the rotors and pads, and rebedding.

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[MLB]

Thanks Flash, I'll try that

Is it the pads that overheated or the rotors (or both)?

I did some straight line speed and braking cycles as part of just giving the car a run, nothing extreme I thought. This could be part of my learning curve for breaking in new brakes on this car in general, and these pads in particular.

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[flash]

hard to tell if it was the chicken or the egg.  i suspect the issue is the rotors, as the mass is larger, and therefore should heat more slowly.  this would tend to open the door for "hot spots" if the rotors weren't warmed up enough, and then you applied hot pads.

 

as a rule, with the porterfields, i let them warm up fairly gradually.  i don't baby them or anything like that.  i just don't do any high speed stops until the car is fully warmed up.  i use that as a time keeper.  i figure by the time the engine is fully warmed up, which takes about 10-15 minutes (yes, the coolant temp comes up faster than that, but the oil does not), i've used the brakes enough to get them warm.  really, it's about getting things under the hood hot, so that the heat soak reaches the rotors and raises those temps a bit.

 

this is harder in cold weather, and can take more time.

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