CCBs Diminished Stopping Power in Wet

[JUSTIFIED]

Pads and rotors are in great shape, but have noticed several times that I must apply a lot more braking pressure when they're wet. Based on what I've read, this is likely due to the rotors cooling off. For example, it was raining quite heavily the other day and I drove through some standing water (just deep enough to get rotors wet and had just left my home so rotors weren't warmed up). I then came to a stop light and braking power was significantly diminished. If not paying attention, it's a bit alarming as it feels as if the brakes aren't working. However, apply more pressure and then they bite.

Anybody else experience this?

Edit: I understand that when wet the pad/rotor friction is reduced, but honestly haven't ever noticed this in any other vehicle. Just pointing this out in case someone informs me of the obvious. :-) Just wondering if others are experiencing the same.

[kramard]

Originally Posted by JUSTIFIED

Pads and rotors are in great shape, but have noticed several times that I must apply a lot more braking pressure when they're wet. Based on what I've read, this is likely due to the rotors cooling off. For example, it was raining quite heavily the other day and I drove through some standing water (just deep enough to get rotors wet and had just left my home so rotors weren't warmed up). I then came to a stop light and braking power was significantly diminished. If not paying attention, it's a bit alarming as it feels as if the brakes aren't working. However, apply more pressure and then they bite.

Anybody else experience this?

Interesting. I do get this after touch less car wash but never figured out my why. Braking is dangerously bad - last for two minutes and about 10 20mph - 0mph stops. My z was a daily for 1.25 years though and never have I had what your describing happen on the street or track in rain and I got caught out in some heavy rains. I never figured out what’s happening at the car wash but I know exactly what you’re talking about.

[Mark_Z28]

I've definitely noticed this. Especially after car washes or driving thru heavy rain. The initial breaking instance always giving you an oh shxt moment and then afterwards they're fine. I actually thought it was a surface tension thing with water and the porous surface of the rotor and pad skimming along on the water surface as opposed to the rotor surface until the surface layer is disrupted but that was just an idea. I got used to prepping myself in rain for this and testing/priming the breaks when its seriously wet outside

[JUSTIFIED]

Originally Posted by Mark_Z28

I've definitely noticed this. Especially after car washes or driving thru heavy rain. The initial breaking instance always giving you an oh shxt moment and then afterwards they're fine. I actually thought it was a surface tension thing with water and the porous surface of the rotor and pad skimming along on the water surface as opposed to the rotor surface until the surface layer is disrupted but that was just an idea. I got used to prepping myself in rain for this and testing/priming the breaks when its seriously wet outside

Just read the information below on a BMW site (excerpt from a manual).... assume ours behave similarly. Many of them state that they've nearly wrecked due to this behavior. I've not experience anything like that, but still alarming when it occurs. Just watch out for M drivers behind you in the rain. ;-)

Seriously... for those of you who are new to the Z and will drive in the rain, be careful because the brake fade is significant (esp. if rotors are cool).


If the brake disc and pads become wet, all brakes undergo a drop in their friction coefficient. M carbon ceramic brakes normally have a considerably higher coefficient of friction than conventional brakes, and they feel considerably fiercer in operation. However, under the impact of moisture and road salt, for example after using a car wash, or when condensation has formed overnight, the braking effect may be equivalent to that of a conventional brake system. This may be perceived as reduced braking performance, but it can be compensated for by applying more pressure with the brake pedal; this should be continued until the pads and discs have fully dried out. Since the difference in frictional coefficient between dry and wet brakes is higher than normal with M carbon ceramic brakes, it is felt all the more clearly by the driver.

[tstodii]

Yep!! Every time I would run the Z in the "touchless" car wash this would happen. I chalked it up to a thin layer of water, soap and wax on the rotors but never looked deeper as it was only in car washes. It freaked me out the first time b/c I was rolling up to a stop sign and the car just kept going until I applied aggressive pedal pressure. After that first time, I would just drive around the parking lot once while riding the brakes to clear the mess up. After one lap around the gas station brakes were back to normal.

I never experienced this sensation anywhere else but I tried my best to not drive in the rain. Mostly b/c SC drivers are wonderful at playing bumper cars in the rain

[_Chigga]

yup definitely experienced this from last couple days in DFW with all the rain coming down.

[Biergut]

Good to know and thanks for the heads up!

[FLOW TIE]

JOHN,
This is a trick question...
You know you should never drive your Z in the rain!!



“Trick question”
-Sam Malone

https://youtu.be/-UceIzK4i3g

[JUSTIFIED]

Originally Posted by FLOW TIE

JOHN,
This is a trick question...
You know you should never drive your Z in the rain!!



“Trick question”
-Sam Malone

https://youtu.be/-UceIzK4i3g

Ha! Black Zs can handle the rain. The AGM...not so much.

[Zslash28]

Yes, nearly rear ended someone the first month of owning the car. Now I make sure to not drive in the rain, and to give extra braking distance, if driving in the rain.

[Palutz]

I’ve noticed this as well after a car wash. I now give myself some extra warm up time before driving with an attitude.

[Og Neon]

No problems here in the rain!