increased drag on 1 wheel, replace rear caliper, wheel bearing, or parking brake?

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Mark..., May 28, 2023.

  1. Mark...

    Mark... New Member

    Joined:
    May 28, 2023
    1
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    Location:
    Wilmington, DE
    Vehicle:
    2015 Prius v wagon
    Model:
    Four
    My 2015 Prius V (or v whatever)'s mileage dropped by like 4 mpg over the winter. It's got 139,000 miles on it. When I jacked it up to switch out the snow tires I noticed the right rear wheel didn't spin as freely. FYI I check caliper slide pins regularly (after 1 froze on my 2012 Gen 3) and they're fine.

    Last year I replaced the wheel bearing on my Gen 3 2012 Prius 3. I figured it might be the same problem so bought a timkin wheel bearing from Rock Auto.

    Yesterday I went to replace the wheel bearing, but once I removed the caliper the rotor seemed to turn freely. I also noticed to my surprise the rear parking brake is a drum as opposed to integrated into the caliper on my Gen 3. The rotor was rusted on and I didn't have the right bolt to press it off, so I put everything back together. Once I put the caliper on the drag was back.

    I tried to search youtube but I literally couldn't find any content for the Prius V - changing wheel bearing or rear brakes. It's all standard prius content. I've never touched a drum brake before so I'm not certain what to do that this point.

    Option 1: Buy new right rear brake caliper, replace, see if drag is resolved - this is easy and what I will likely do. These simple calipers are pretty cheap, OEM is like $100 from McGeorge.

    Option 2: Remove rotor, try to figure out if parking brake is dragging or wheel hub needs replacement - this is intimidating as I've never seen or touched a drum brake. I'm a perfectionist so am interested in making sure everything is good in there, but don't want to break something that's working fine! I'll probably only do this if replacing the caliper doesn't fix drag problem.

    Anyone have any experience replacing a Prius V wheel bearing / parking brake? Or any tips on rear caliper replacement? Or different ideas about this increased drag? For my Gen III I've been spoiled by the excellent Nutz about boltz content, which I'm not expecting, but any tips are appreciated.
     
    #1 Mark..., May 28, 2023
  2. SSAutomotive

    SSAutomotive Junior Member

    Joined:
    Dec 15, 2021
    18
    2
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    Location:
    Stewartstown, PA
    Vehicle:
    2011 Prius
    Model:
    Two
    Rear caliper off and free spin means a bad caliper, 100%. Probably a seized or partly seized piston. Often times people forget to change out brake fluid. It is hydroscopic meaning it draws in water, and that results in corrosion. Follow manufacturers guidelines as it's easy preventative maintenance. Change caliper and replace all fluid.

    For future reference, bad wheel bearings will often times make noise, and when pushing a wheel from the tire edge on the X and or Y axis, it will have play. With rotor off and only hub on, spin the hub and that will be a giveaway.

    In terms of the rotor, the best PB blaster formula is 90% acetone and 10% vegetable oil. Or just presoak overnight and hit with a mallet. Replace rotor if you hit it too hard, it's brittle metal. Good luck.
     
    #2 SSAutomotive, Jun 21, 2023
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