Brakes Grinding Only When Wet?

[SW03ES]

Hey guys,

We just got home from visiting the in-laws to be in New Jersey. It rained really hard the whole way back and I noticed something I've noticed a couple of times before again only when its raining. After driving at high speed in the rain, the brakes grind REALLY bad when slowing the car, and there also seems to be a loss of braking effectiveness (pedal feels hard).

This is directly proportionate to the amount of rain. By the time we got on the beltway the rain had stopped and braking returned to normal. Braking was normal driving up there, and before it started raining. It only happens when its raining moderately or heavily.

Car has about 17,000 miles on it so I dont think its bad pads yet, as the brakes are fine at all other times. I checked all the rotors out really well with a flashlight just now and there doesn't seem to be any scoring of the rotors or excess brake dust.

Whats everyone think? This is definately abnormal and is a new problem. The car never used to behave this way in the rain.

[SW03ES]

Nobody has any thoughts huh?

I called the Lexus dealer and he thought it was very strange. He said what I already know, that usually when you have grinding brakes the rain actually LESSENS the grinding as it acts as a lubricant. He suggested I drive it a few more days and see if it returns, if it does he'll replace the front brakes and claim it under the vibration TSB and see what that does.

Dry today, no grinding. Washed the car, no grinding.

[chadmg7]

Is something expanding possibly from the moisture, causing the grinding noise? I'm not sure... just taking a stab at the problem, maybe to spark an idea.

[loco1216]

I have precisely the same problem with 6000 miles ES330 and was wondering if I should report this. I'm glad I'm not the only one. I hope that if I report it, I won't get an answer like, Operating as designed

[iammikey]

I have an '04 with over 14,000 miles and I haven't experienced that. It was raining in my area all last month and I must have put around 1000 miles in the rain without noticing that.

Were your wheels submereged under water for any amount of time? My Nissan souded like it was grinding anytime I drove through deep puddles and the dealer stated that semi metallic brake pads will sound like that after driving through puddles.

[SW03ES]

loco-

My service rep definately did not think it was operating as normal. He's a good guy and I have no doubt he can get to the bottom of this. Its going in on Wed. and they're going to do a complete check of the brake system and perform the brake vibration TSB (replacing the rotors and pads in the front) and see what that does.

I'll keep everyone posted.

iammi- Mine never did this either until recently, and I have 17,000 miles so you should keep an eye on yours also. The wheels were never submerged but it does feel as if they had been, its almost like the pads get no traction on the rotor and then all of a sudden they do and the right front wheel lets out a TERRIBLE audible and sensible grind and finally you get some braking power back. My fiancee was in the passenger seat asleep and it was enough to wake her up and ask what the hell it was. It sounds like a truck's jake brake if you've ever heard one of those. Its NOT subtle in the slightest. It also only happens at highway speeds, like slowing from 80 onto an offramp or something. At low speeds braking is normal.

Drive carefully in the rain and give yourself plenty of stopping distance when you're at highway speeds in the rain because its definately VERY dangerous. If I hadn't gotten on the brakes to gradually slow for a curve and waited for an offramp or a critical situation to realize the problem we could have had a very serious accident.

If this is a chronic ES problem this is DEFINATELY safety recall complain to the NHTSA type of stuff.

We were out in the car all evening, dry weather and the brakes are 100% normal. Damndest thing...