Brakes locking

Discussion in 'Gen 4 Prius Main Forum' started by Clifford Bradford, May 20, 2021.

  1. Clifford Bradford

    Clifford Bradford Junior Member

    Joined:
    Nov 11, 2019
    13
    7
    0
    Location:
    Cincinnati
    Vehicle:
    2016 Prius
    Model:
    Two
    So I have a 2016 Base model (64000+ miles) and ever since I've owned it (owned since new) one problem I've consistently had with the car is with the brakes. They can lock up if you either jab on them or press hard. And by lock I don't mean momentarily I mean old-fashioned, full-on, multi-second, tire-smoking lock. Most recently I was driving in the rain at around 40-50 mph going down a hill on smooth pavement and I had to brake as the cars in front of me came to a stop unexpectedly I hit the brakes and they locked up, ABS never kicked in. I tried easing off the brakes to get the wheels rolling but it didn't help. I eventually hit the car in front of me at maybe 5mph. Luckily the driver and I were both OK and neither car was damaged.
    This isn't the first time I've fully locked up in the car. I've locked this car up more than any car I've ever owned including a few that didn't have ABS. To me the brakes work fine if you can stop smoothly and gently but since they have little to no feel they can be hard to brake well when you need to brake hard and rough, wet, or otherwise dodgy surfaces don't help.
    I'm just trying to find out whether my experience is normal
     
    amos likes this.
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    14,679
    10,311
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Reminds me of a phone conversation I had years ago with a tech support guy at USRobotics. I told him a detailed story of what my USR modem was doing, what happened when it was supposed to connect, and when I finally stopped for air he said:

    "Sounds broke."

    So he sent me one that warn't broke.
     
    privilege likes this.
  3. jerrymildred

    jerrymildred Senior Member

    Joined:
    Oct 28, 2016
    10,081
    12,359
    0
    Location:
    Tampa, FL
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Premium
    Locking brakes on an ABS-equipped car are never normal. I'd have in the dealer's shop asap. But if it's intermittent, they might have a hard time diagnosing it.
     
    Tande, alanclarkeau and amos like this.
  4. amos

    amos Active Member

    Joined:
    Aug 19, 2017
    319
    274
    0
    Location:
    los angeles
    Vehicle:
    2016 Prius
    Model:
    Two
    Is the cruise control working?. If not than something could be wrong with abs or sensors on front wheels?
     
  5. Mendel Leisk

    Mendel Leisk Sand Pounder

    Joined:
    Oct 17, 2010
    45,571
    32,535
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I have noticed touchy brakes, on our 3rd gen. Typically at start up, mostly in reverse IIRC. First time I was backing up in a parallel parking space, in prep to exit: touched the brake and thought I musta tapped the guy behind; it was so abrupt and total stop. My hunch is the electronics at play, not mechanical.
     
    #5 Mendel Leisk, May 20, 2021
    Last edited: May 20, 2021
  6. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    15,336
    8,629
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    Since new? That would have made it a warranty failure back then, but unfortunately the basic warranty for that level of non-hybrid components is probably long expired by now.

    Just to confirm that the brakes are really locking: you are smoking the tires when this happens on dry pavement? Leaving skid marks? And sliding/skidding and losing steer control on that wet downhill?

    I must ask because the Prius ABS feels much different than on my prior car, and is much smoother without the old familiar rapid pulsation. In dry conditions it feels like it is trying to dig up the pavement. And with the electronic Brake Assist (BA) feature, it was surprisingly easy to inadvertently trigger full panic-level ABS braking when I "either jab on them or press hard", until my reflexes were re-trained. But in my cases, it was not actually locking up, the stops were still perfectly straight. And quick.
     
    jerrymildred and alanclarkeau like this.
  7. Clifford Bradford

    Clifford Bradford Junior Member

    Joined:
    Nov 11, 2019
    13
    7
    0
    Location:
    Cincinnati
    Vehicle:
    2016 Prius
    Model:
    Two
    In this last case they were fully locked. I wasn't trying to steer so I can't comment on the lack of steering control. I could sense being on the far side of peak rolling friction. I've driven the car for long enough to know to be careful in the conditions where it's a problem but in this particular situation I was taken by surprise. I've locked them on dry pavement and made tire smoke.
     
  8. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    14,679
    10,311
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Do you have access to Techstream? What information is saved in the ABS activation history?
     
  9. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    5,763
    2,289
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    NO, absolutely NOT normal.
    And probably dangerous too.
    I can't imagine you NOT taking it to get it fixed after hitting another car with no ABS activation.

    BUT.....some tests on a deserted road or empty parking lot might be in order.
    Wheels will sometimes skid a little bit even with ABS activation.
    But it doesn't sound right to me.
     
  10. MPGboss

    MPGboss Junior Member

    Joined:
    Mar 3, 2021
    75
    42
    0
    Location:
    Los Angeles
    Vehicle:
    2021 Prius
    Model:
    XLE
    kick it on the side, might help! but seriously that sounds dangerous.
     
  11. Clifford Bradford

    Clifford Bradford Junior Member

    Joined:
    Nov 11, 2019
    13
    7
    0
    Location:
    Cincinnati
    Vehicle:
    2016 Prius
    Model:
    Two
    It's going in in the near future.
     
  12. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    94,773
    42,984
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    i have to wonder about driving style, since i have never locked up the brakes in 50 years of driving over 40 or 50 different cars
     
    Pulse07 likes this.
  13. Pulse07

    Pulse07 Member

    Joined:
    Feb 24, 2020
    148
    80
    0
    Location:
    California
    Vehicle:
    2020 Prius
    Model:
    XLE AWD-e
    Same (although much less years and cars) .
     
Loading...