Need for continued brake slider maintenance

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by tedjohnson, Oct 30, 2014.

  1. dorunron

    dorunron Senior Member

    Joined:
    Jul 17, 2011
    3,318
    1,086
    0
    Location:
    Houston, TX
    Vehicle:
    2013 Prius
    Model:
    Three
    The 15 I looked at appeared to be the same as the 13 we have bisco
     
    bisco likes this.
  2. Former Member 68813

    Former Member 68813 Senior Member

    Joined:
    Oct 3, 2010
    3,524
    972
    8
    Location:
    US
    Vehicle:
    Other Hybrid
    Model:
    N/A
    I always thought the drum disks were self-adjusting?

    Some other sources agree:
    Before 1955, drum brakes required periodic adjustment: Drum Brake Self Adjusters: Understanding These Ancient Devices
     
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    90,006
    40,378
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    both of our gen II's are over 100,000 miles with perfect, untouched front and rear brakes. i can't speak for stopping distances though.
     
  4. dorunron

    dorunron Senior Member

    Joined:
    Jul 17, 2011
    3,318
    1,086
    0
    Location:
    Houston, TX
    Vehicle:
    2013 Prius
    Model:
    Three
    It is my opinion that all rear drum brakes only adjust when backing up. I could be wrong, but that is my understanding. I did read that also activating the parking brake will cause the adjuster to work...

    Not everyone uses the parking brake and not everyone will back up quickly and stop firmly to make the self adjuster's work properly...

    Quote from article:

    The adjustment takes place when the vehicle is in reverse and the brakes are applied or when the parking brake is engaged. The cable or link attached to the anchor pin pulls the lever mechanism based on the movement of the secondary shoe.

    End of Quote.

    Source: Drum Brake Self Adjusters: Understanding These Ancient Devices

    Ron (dorunron)
     
    Den49 likes this.
  5. Former Member 68813

    Former Member 68813 Senior Member

    Joined:
    Oct 3, 2010
    3,524
    972
    8
    Location:
    US
    Vehicle:
    Other Hybrid
    Model:
    N/A
    OK, maybe one should.
     
  6. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    90,006
    40,378
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    i once knew a lady who was scared to back up, always parked her car so she could proceed forward.
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    40,850
    29,339
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    As I posted earlier, I suspect it's mandatory to ensure the rear brake pads are very firmly in contact with the caliper piston face after assembly, before the parking brake is ever applied. This locks the cross pattern on the piston face against the pin on the back of the inner brake pad, prevents it from rotating.

    I've got pics of the pad backs, from the first time I took them out, and the pin on back of inner pad was already a bit chewed. Which leads me to think the factory floor assemblers are not ensuring good contact. And further, that the design is excessively finicky, shouldn't require this amount of attention, should be revamped. Say a mini-drum, as mentioned. Or something, anything, a bit more bullet-proof.
     
  8. Den49

    Den49 Member

    Joined:
    Oct 25, 2010
    498
    264
    0
    Location:
    Maryland
    Vehicle:
    2010 Prius
    Model:
    IV
    Drum brakes have a self adjusting lever on top of a toothed wheel that turns a screw to adjust the brake shoes outward when the brakes are applied firmly to stop the car in reverse. Problem is this feature is usually insufficient to keep the brake shoes in proper adjustment because of one or more of the following common conditions/practices:
    - not operating the car in reverse often enough so the adjuster does not operate often enough to compensate for wear of brake shoe material
    - not stepping firmly enough on the brake pedal to cause the adjuster to operate
    - the self adjusting mechanism binds and stops working due to lack of lubrication and corrosion

    The above is why periodic manual adjustment of drum brakes is necessary, but unfortunately not done often enough by the general car driving public.

    The brake system is the most important safety system on a car; however, it is also one of the most neglected in terms of needed preventive maintenance.
     
    #28 Den49, Nov 2, 2014
    Last edited: Nov 3, 2014
    dorunron likes this.
  9. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    90,006
    40,378
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    probably cause they hardly ever fail.
     
  10. Jonny Zero

    Jonny Zero Giggidy

    Joined:
    Jun 22, 2012
    1,388
    350
    0
    Location:
    Austin, TX
    Vehicle:
    2012 Prius
    Model:
    Five
    Does this apply for us in the South with no salt?

    Does using the parking brakes regularly help keep the pins from freezing?
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    40,850
    29,339
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Don't think so. But it's good for keeping the parking brake cables in good working order. Takes a load off the transaxle parking pawl, good idea if you might jack up a corner, or the front end, and just generally safer too.
     
  12. Indy John

    Indy John Member

    Joined:
    Jul 16, 2008
    75
    33
    0
    Location:
    Indianapolis
    Vehicle:
    2010 Prius
    Model:
    Two
    "Rear brakes work harder than the rear brakes on a conventional front-drive car due to regenerative braking" = nonsense. Regenerative braking is accomplished via electrical drag in the MG, transferred via the PSD to the front wheels only. Prius rear brakes see less use than any conventional car, and the presence of a 130-lb. battery is not a factor. Disc brakes need slide pin maintenance. Period.
     
  13. tedjohnson

    tedjohnson Member

    Joined:
    May 21, 2010
    342
    63
    0
    Location:
    Greenfield MA
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    I suggest you start checking the temp of the brakes when you come to a stop. The fronts will be cool the backs always warm on my Prius. It really does seem like the rears are getting the brake action while the fronts stop by regen....
     
  14. Jonny Zero

    Jonny Zero Giggidy

    Joined:
    Jun 22, 2012
    1,388
    350
    0
    Location:
    Austin, TX
    Vehicle:
    2012 Prius
    Model:
    Five
    What he means is: Prius front brakes do less work than a conventional car, Prius rear brakes do the same amount of work as a conventional car.

    So, albeit the the rear brakes do more work than the front on the Prius, it does not imply the rear brakes do more work than the rear brakes on a conventional car.
     
  15. Den49

    Den49 Member

    Joined:
    Oct 25, 2010
    498
    264
    0
    Location:
    Maryland
    Vehicle:
    2010 Prius
    Model:
    IV
    When I said this it was based on my personal observations and experience maintaining and replacing brakes on the ten conventional cars I have owned in the last forty years, and now maintaining the brakes on my two hybrid cars, since 2009 on my Prius and 2013 on my Avalon hybrid. The conventional front wheel drive cars I have owned that are comparable to the Prius (Corolla and Camry) exhibited much less rear brake wear than what I am seeing on my Prius. It is too early to tell on the Avalon.

    In my opinion, regenerative braking and a heavy hybrid battery are logically attributive factors. Regenerative front braking causes the front friction brakes to do less work and wear less; however, the rear friction brakes have to perform all the braking work for the rear wheels since there is no regenerative rear braking. Anything that makes the rear of the car heavier, such as the hybrid battery, requires more, not less, work to be performed by the rear brakes to safely stop the car.

    I could be wrong, but I don't think I am in any way nonsensical. Nonsense is when you use that word but offer no supporting rationale or evidence for your contrary opinion.
     
  16. Den49

    Den49 Member

    Joined:
    Oct 25, 2010
    498
    264
    0
    Location:
    Maryland
    Vehicle:
    2010 Prius
    Model:
    IV
    I hope you are NOT trying to speak for me. That is not my opinion.
     
    #36 Den49, Nov 6, 2014
    Last edited: Nov 6, 2014
  17. Jonny Zero

    Jonny Zero Giggidy

    Joined:
    Jun 22, 2012
    1,388
    350
    0
    Location:
    Austin, TX
    Vehicle:
    2012 Prius
    Model:
    Five
    I was paraphrasing IndyJohn.
    "Rear brakes work harder than the rear brakes on a conventional front-drive car due to regenerative braking" = nonsense. Regenerative braking is accomplished via electrical drag in the MG, transferred via the PSD to the front wheels only. Prius rear brakes see less use than any conventional car, and the presence of a 130-lb. battery is not a factor. Disc brakes need slide pin maintenance. Period."
     
  18. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    40,850
    29,339
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    FWIW, when I do a walk 'round and feel brake temp after a drive, they all feel about the same, just slightly warm. The rears are little if any warmer. But then I've been going ballistic with rear brake maintenance, replaced the pads (pins relubed recently, too), really careful with reassembly, the parking brake rigamarole. I hope I've got it right...
     
  19. frodoz737

    frodoz737 Top Wrench

    Joined:
    Aug 26, 2010
    4,267
    2,274
    33
    Location:
    Texas
    Vehicle:
    2015 Prius
    Model:
    Four
    What you have right is that you do "a walk around" and maintain your vehicle. (y)
     
    Mendel Leisk likes this.
Loading...