Brake Noise After Gs300 Has Been Sitting For Over 5Hrs

[njerwood]

Hello all

I have a problem with my brakes making a squealing noise after the car sits for over 4 to 5 hours. When i pull off or back up, the brakes will squeal for about 2 minutes but only when i press on the brakes. Then the sound goes away. I went to dealership and they tried to tell me that this is common for this vehicle. Which is a horrible answer. Also i get quick brake rust on my rotors overnight if it rains. Can anyone tell me what i can do about this? pads and rotors are fine and no squeal when i drive after this initial noise.

thanks

[GDixon]

Hello all

I have a problem with my brakes making a squealing noise after the car sits for over 4 to 5 hours. When i pull off or back up, the brakes will squeal for about 2 minutes but only when i press on the brakes. Then the sound goes away. I went to dealership and they tried to tell me that this is common for this vehicle. Which is a horrible answer. Also i get quick brake rust on my rotors overnight if it rains. Can anyone tell me what i can do about this? pads and rotors are fine and no squeal when i drive after this initial noise.

thanks

That is just how it is. Almost all cars will squeal with rust on the rotors. Here in CA the same thing happens in the summer when the car is washed. It is just something to get used to and does no damage.

[nc211]

Actually, it's not quite exactly how it is. Is it something that will damage the car or your stopping ability? Nope, not at all. Is it annoying? Oh yeah. All rotors will "flash rust" after a rain/car wash if left to sit. You'll hear that sandpaper noise at first as the rotors clear that rust. That's normal. The squealing is due to a torn anti-squeal shim on that brake, assuming you still have your original pads (or genuine oem pads with the shim kit reused from the old pads). Toyota brake pads have this clip that goes over the back of them, that is made up of two parts. First is this thin piece of metal that is wrapped in a rubber case - that goes directly onto the back of the pad. Second is a metal clip that sandwiches the rubber wrapped piece to the pad. This metal piece is what your piston pushes against when you apply the brakes, which in turn pushes the pads onto the rotor. If the rubber casing piece sandwiched between the two gets torn, or is not greased when installed, then the harmonic vibrations from the pad surface and rotor come through to the rest of the assembly, causing that squealing noise. After a couple of minutes however, the noise goes away, because the heat of the brakes have softened up the rubber better.

My 4runner's front driver side wheel does this exact same thing. I known the rubber piece is torn, as I had changed the rotors and pads about 18 months ago myself. When I was doing this, I noticed one of the caliper pistons had rusted pretty badly "nothern winter road salt", which had created an uneven pressure surface against the piston and the metal backing clip. Eventually, the metal clip had rubbed ever-so-slightly enough rubber from the anti-squeal shim (the rubber piece) to expose the metal....and it screams on the first application of the brakes when in reverse (backing out of the driveway) after a rain/snow/carwash. Lasts only a few seconds.