Brake question: wet rotors

This happens every now and then in really muggy weather, or in huge turd floaters. Pull out of the driveway and the first stop sign hit the brakes and pretty much nothing happens, the car keeps rolling at a happy place for a few feet untill I give it hell then the pads finally contact with a loud HONK and the car abruptly skids and stops. After that first stop the rotors are clean and the car stops fine. It's not that big of a deal, more annoying than anything but if there had of been a child or a dog run out in front of me I would have slowly rolled into them.

I have heard this isn't out of the ordinary after rolling through more than 10 inches of water or lots of condensation getting the rotors wet. My question is this, would slotted rotors fix this problem? I know that slotted / drilled rotors are pretty much worthless on the street and on street pads, but if they'll fix this then I might put them on my list of things to do this spring.

Interestingly enough, the Miata is the only car I've driven that does this, and it does it alot. The Element has never done it, and my 3 civics preceding it never did it, Two of them didn't have ABS and one them had either 13s or 14s (can't remember, but it was an 87 hatchback) and I hit some massive puddles in it.

Thoughts?

I use DBA drilled/slotted for street use and will use them on a rainy track day if I ever have one. Are you sure your master cylinder is good? Does this happen with a fresh fluid change too?

Back when I was running 1.6 brakes on my car, I did experience some of the rain issues you describe. I switched to slotted rotors and it went away. When I went to 1.8 brakes, I went back to stock style rotors. I don't recall ever having the problem with the 1.8s, but I also stopped daily driving the Miata around the time of the switch so the car rarely sees time in heavy rain now.

Happens to me every now and then in the Miata, but my old BMW was really bad about it. The brake system was fine, so I just trained myself to dry the brakes occasionally while driving down the road.

I had it happen the other day while traffic was checking up on 183 at central. I had been on the highway for 20-25 minutes and I can't remember if I had used the brakes at all. The cold and the wet probably combined, but it was a heart stopping moment until they started to grab.

If you check the pointboard there was write ups on this issue with the very early NB. The porblem was "fixed" after Mazda put a "water shield" on the caliper. I have the shields but I still has this porblem when I run over a big puddle. when I was learning to drive, I was told to heat up the brakes to dry out the rotors every 10 minutes or so when driving in the rain. I have been do this ever since.

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Originally Posted by gabkwong

I have the shields but I still has this porblem when I run over a big puddle. when I was learning to drive, I was told to heat up the brakes to dry out the rotors every 10 minutes or so when driving in the rain. I have been do this ever since.

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Me too on both accounts!

Anyone have a lead on some decent TCB slotted rotors? I haven't researched the topic of rotors since the ol' Honda, but I know there's a ton of crap ricer parts out there.

I'm thinking switching out just the fronts, I don't think the rears would be worth switching right?

Testing the brakes every so often it probably a good idea. I normally test new road surfaces anyway in bad weather, but i'll remember to keep the brakes clean.

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Originally Posted by Nails

I use DBA drilled/slotted for street use and will use them on a rainy track day if I ever have one. Are you sure your master cylinder is good? Does this happen with a fresh fluid change too?

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Your rotors will be hot enough that water spray won't cool them enough to matter, but you should block those brake ducts.

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Originally Posted by trickyrix

Happens to me every now and then in the Miata, but my old BMW was really bad about it. The brake system was fine, so I just trained myself to dry the brakes occasionally while driving down the road.

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Whoa, I just had a flash-back to a time when driving a car required intelligence. Luckily a few car companies have equipped our transportation appliances to dry rotors automatically, removing the need for cognitive from the driving process, again.

I've got the slotted/drilled ones I took off my car earlier this year. Not sure how much life they have in them but they still stop smoothly. PM me if you want em - they're just taking up garage space at this point.

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Originally Posted by Jiggerachi

Anyone have a lead on some decent TCB slotted rotors? I haven't researched the topic of rotors since the ol' Honda, but I know there's a ton of crap ricer parts out there.

I'm thinking switching out just the fronts, I don't think the rears would be worth switching right?

Testing the brakes every so often it probably a good idea. I normally test new road surfaces anyway in bad weather, but i'll remember to keep the brakes clean.

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