Brakes binding up and causing poor fuel economy

Discussion in 'Gen 2 Prius Fuel Economy' started by T.S. Elliot, Sep 4, 2018.

  1. T.S. Elliot

    T.S. Elliot Junior Member

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    Hello all. I have a 2007 Prius that has been consistently getting 38-42 mpg all summer. I just replaced both batteries in this bitch so she doesn't have any more excuses. I have determined that the cause of the poor mileage is that the front brakes are binding up. The front tires don't rotate freely. The rears do spin free, with one small spot of friction (which I read is normal can anyone confirm this?). The rotors are hot after a drive without intense braking. I replaced the brakes myself with Raybestos rotors and Wagner thermoquiet pads about a year ago. I thought I knew what I was doing, but apparently not. Either that or something went wrong with the calipers over the course of a year.

    How do I fix this problem? The rotors still look fine. First thought would be to keep them, but I am just so done with this problem I don't want to run the risk of keeping them. What if they are too thick? etc. I could take it to Toyota and say replace the front brakes and make sure they don't bind. But I will pay out the nice person for it and maybe get a car back with the same exact problem. "The brakes are still binding". "Sorry we just replace the brakes, we don't fix binding problems." My appetite for more DIY is pretty low. I don't mind doing DIY when I can, but trying to troubleshoot a problem is just too frustrating. I replaced the HV battery myself and it was a nightmare. A miracle the car started. No one told me you would have to rewire the battery.
     
  2. Mendel Leisk

    Mendel Leisk Titanic Social Director

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    You can check your rotor thickness and runout with spec's in the attached.

    Front wheels will NEVER rotate freely, due to being connected to the drivetrain. They will turn, but it's takes a moderate effort. That said, they should not be hot after a normal drive, slightly warm at the most.

    Have you opened up the brakes since that last time? I'm wondering: are the inside and outside pads wearing evenly? If one pad is wearing more than the other it could be a sign of piston sticking. Also, did you lube the caliper slide pins, and if so what did you use? For starters just check if the caliper slide pins are moving fairly freely.

    When you did the brakes did you disconnect the 12 Volt? That's good practice, could avoid a mishap: the brakes pressurizing while the caliper's off the rotor could eject a piston.
     

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  3. T.S. Elliot

    T.S. Elliot Junior Member

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    Hi thanks for the reply. I thought with the car being in neutral the fronts should spin freely. I guess even in neutral they are still somewhat connected to the transmission. They're pretty damn stiff though and the rotors get too hot to touch.

    I have not opened the brakes since a year ago. Suspiciously enough I am starting to get the same sound on these brakes as I got when the original ones started going out even though they are only a year old at max.

    I did disconnect the 12v when doing the brake job, but I did not lube the slide pins. I remember the job being a bitch. I had to fight 10 years of rust. I don't know much about brakes aside from the obvious. Your advice on looking at the pads seems prudent, but again, I don't really know what I'm doing. It may just create additional problems, and who knows if I can get everything reassembled properly.
     
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  4. Dxta

    Dxta Senior Member

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    Then you need someone to fix em, and you pay!
     
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