C1256/1391--anyone ever try using DOT4 brake fluid?

Discussion in 'Gen 2 Prius Technical Discussion' started by TMR-JWAP, Feb 8, 2021.

  1. mr_guy_mann

    mr_guy_mann Active Member

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    Perhaps you had a bit of grit stuck in a valve, and removing the accumulator allowed enough fluid to push it out when you powered up afterwards?

    Posted via the PriusChat mobile app.
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    Another update. Kind of. A handful of months ago, I purchased a 2008 Driftwood Pearl while taking a few days off in Myrtle Beach. 275 k miles, excellent body, leather interior, etc. Only problem? C1345/C1368 linear valve codes. Actuator cycling frequently, but no accumulator codes. PO had bought it from a Toyota dealership about 2 months previous. Dealer tried to clear codes, would not relearn. Told PO it needed to have actuator replaced. PO said heck with it and put it up for sale. I bought it for 1k and drove it home. No noticeable issue except brakes were a little grabby when below 10mph. Car has already paid for itself +$200 via OEM catalytic converter.

    This evening, I let the car warm up and timed the cycles. Every 18 seconds the pump would start. Timed 30 cycles. Used techstream to empty the accumulator to the reservoir to maximize how much fluid I could change. Used the ol' flavor injector to remove as much fluid from the reservoir as possible and then filled with fresh Prestone DOT3. Closed hood, put car in ready and let it sit for 30 minutes with heater on so engine would stay running and get everything warm. Timed 30 more cycles. 23 seconds. Unfortunately, it still will not learn, but that's not unexpected. Just experimenting with cycle time.
     
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  3. ColoradoCrow

    ColoradoCrow Junior Member

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    Interesting findings.
    There is a similar ABS Accumulator that fails in the Generation 2 Range Rover P38 which I own so I'm keen to learn more about the Toyota system. So....my take away is that a DOT 3 brake fluid refresh every 100K miles might prolong the life of the accumulator but still it seems these accumulators fail about 200K?
     
  4. heltonsc

    heltonsc Junior Member

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    thank you so much! it works! i have a gen 3 2013 and the actuator was running every 35 seconds.

    1- I disconnected the 12v battery

    2- I pressed the brake several times to empty the accumulator.

    3- I drained all the fluid from the tank

    4- I added 1 bottle of dot 4 fluid

    5- I connected the 12v battery

    And at the same time the car was perfect! the brake pump no longer runs alone! it's like a new car!

    greetings from Brazil to all friends of priuschat

    @TMR-JWAP
     
  5. heltonsc

    heltonsc Junior Member

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    Today after a few days with the dot4 the pump started to run every 1 minute sometimes.

    How is your car today? put dot4 solved your problem? the pump turns on every how many seconds? Any DTC?

    @TMR-JWAP
     
  6. TMR-JWAP

    TMR-JWAP Senior Member

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    I didn't put the DOT4 in it, just fresh DOT3. I lent the car to a friend last Saturday and he's been driving it all week. We spoke yesterday and no mention of any problems.
     
  7. frodoz737

    frodoz737 Top Wrench

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    It is my hope that one day Prius owners will finally learn that the brake fluid must be routinely flushed and transmission fluid routinely changed as a part of preventative maintenance.
     
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