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My trusted mechanic pointed out to me during my last oil change that I should replace the rear Rotors and Brake Pads on my GS450h. I attached two photos of each of the rear rotors from my car. Notice that almost a good 1/3rd of the outer edge of the rotors are rusted. My mechanic explained that the rear brake pads isn't making contact with the rusted portion of the rotor. This will result in reduced braking performance.
I'm wondering if it's actually necessary to do the rear brake job. In a perfect world (ie. having plenty of money to splurge to get a car in 100% tip top shape), yes I would do it in a heart beat.... but from a practical standpoint, I'm wondering if it's really necessary. Would it be safe to do it? Sure, especially if it involves safety, but again, is it really necessary?
I'm wondering this because first, this is the REAR brake. In any car, the front brakes are responsible for 65-75% of the braking performance .... thus, the rear brakes are really only there to assist. Second, this is a HYBRID..... so the friction brakes are hardly even ever used. As I understand it, they only go on during heavy braking and under 5-mph. Case in point, I drove around this afternoon for 30-minutes in the city. After I parked my car, I went to touch the rear rotors. It was practically cold... suggesting that they had been barely used since no heat equals no friction. The fronts on the other hand, was hot to the touch, enough to scorch my finger but not as hot as the typical non-hybrid car with conventional friction brakes.
What do you guys think? Please, don't flame! I have every intention in driving a safe car so as to not harm others out in the road. I'm really just wondering if it's necessary for this rear brake job. Thanks!
Personally I would for my own peace of mind. The rear brakes are much cheaper than the front brakes if you have RWD F sport. But as you stated, I see no qualms with not changing them. Your parking brake probably won't work since the pads aren't grabbing anything where it's rusted. If you don't change them out now, then when would you? How long are you willing to drive around like that?
Just put on new pads. I bet the ones on it are aftermarket, just get new oem ones. No need for new rotors. The new pads will bed into the rotor and you will no longer have that rust ring.
I have 85k+ miles on my 450h original front and rear rotors, only use OEM pads, no issues.
Something is out there... That doesn't look like a symptom of normal wear, at least for OEM equipment. I'd take the wheel off and see what the pads look like. Something is probably bent or out of alignment. Could be incorrect or poorly configured pads or a funny calliper.
Has previous work there been done by a good mechanic?
My rear rotors were badly pitted and rusted when I first picked up the car (and it was CPO!) I drove the car and braking was as expected with no juddering. They changed out the front pads/rotors but left the rears in crappy shape. I personally would change them out because your mechanic is correct about the minimized braking performance.
Also, it won't get any better over time. The oxidation, pitting and rusting will continue especially if your car sits outside for a few hours a day. Some good aftermarket rotor options available for non F sport models as well (Centric and its high performance brand Stoptech; ATEPremium Rotors to name a few). Pricing isn't too much different from OEM so its really up to you...
Yes, I think I will just change them out. As some have pointed out, the pads and rotors actually don't cost that much.
I'm not sure why the rear rotors are like that (they are like that on both sides of the car, and both sides of the rotor itself!). Everything on the car is original and there's only 24k miles.
The car drives and stops just fine.
i would change the pads and turn the rotors only. no need to replace the entire rotor unless it isn't thick enough to turn.
while in there inspect the calipers.
I suspect as you said the hybrid system uses regenerative braking so the rear brakes are hardly used.
u let the car sit for too long and collecting rust on the rotor. for me I would recommend the same thing new pads and rotor. I don't resurface the rotor if it looks like that.
10-22-18, 02:00 PM
Should I get new rear Rotors and Pads?
I have every intention in driving a safe car so as to not harm others out in the road. I'm really just wondering if it's necessary for this rear brake job. Thanks!
