Finished replacing booster/accumulator. Brake Bleed Next

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Trafficat, Feb 20, 2025.

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  1. Trafficat

    Trafficat Junior Member

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    47070-47060 is the Brake Booster Pump Assembly with Accumulator for my VIN

    upload_2025-3-5_22-59-20.png

    That's a lot of years. If I'm searching the website correctly, it seems like this might be the only part. I'm not seeing other parts on autoparts.toyota.com that come up for "Prius Booster" or "Prius Accumulator" that look at all similar.
     
    #41 Trafficat, Mar 6, 2025 at 2:02 AM
  2. ASRDogman

    ASRDogman Senior Member

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    Brake parts are things you should not buy used.
    There is almost no way to know if the part was really working or not.
    I would think that maybe the part is not installed correctly, which is why you can't depress the brake
    pedal and the switch didn't line up correctly.

    You could search the internet for photo's of the brake lines to insure you have them on correctly.
    Another possibility is that techstream is not working correctly.

    You need to contact the place you purchased those parts from and get your money back.
    And I think it's time to go to Toyota with the vin number and get the correct parts, NEW parts.

    Having "iffy" brakes puts innocent people on the road at risk, not just you.
     
    #42 ASRDogman, Mar 6, 2025 at 7:57 AM
    Last edited: Mar 6, 2025 at 8:46 AM
  3. rjparker

    rjparker Tu Humilde Sirviente

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    The whole point is the housing number is not the part number. Every year of hatchback has at least two different part numbers, one per tire size. A v wagon is different x2 as well. Used sellers don't know this and foul up guys all the time.

    The pump is more universal but there is a bad design flaw in 2010 production.

    AGAIN, you can't tell by the housing number. You have to buy new and include your vin. You could call one of the online dealers. Most walk-in parts departments won't help unless you buy from them, usually at full msrp. Most oem parts have a wholesale price 50% of msrp.
     
    #43 rjparker, Mar 6, 2025 at 8:04 AM
    Last edited: Mar 6, 2025 at 3:37 PM
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  4. Trafficat

    Trafficat Junior Member

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    I am regretting buying used parts. It was so long between I ordered them and when I installed them that I didn't even remember what I had. Right now, I would have to save up probably until May to buy any new parts, or maybe get a small loan from a family member. The best I can do is the parts I have at the moment.

    So, what I did was I reinstalled the old possibly bad "master cylinder / actuator" that is the correct part and hope it was the old booster that was bad, and I'm going to hope the "new to me" booster from 2010 is not part of the defective manufacturing batch.

    I will probably attempt a brake bleed and calibration tomorrow and hope for the best. When the brake pedal is held down right now, the brake makes the boosty noise constantly which seems a little weird, but I recall that when I reset memory on techstream, prior to starting the bleed operation itself with the "new to me" wrong master cylinder it also made a continuous noise. So I don't know if it's a sign of a bad part or just a sign that it needs calibration or something.

    Hoping for the best tomorrow. If not, I guess I'm going to move the Prius to the side of the yard and put the battery on the charger, save up for new parts, and try again probably in May or so.

    Mystery solved. While I recently concluded that the wrong part was the cause, I actually now believe it is just the process of changing the actuator that can easily disturb the sensor bracket. (It wouldn't touch in post #8 and I bent to touch in #13).

    When I installed the old master cylinder / actuator again, and I was trying to insert the retaining pin to link the push rod to the brake pedal, this time I was working from a different angle and I observed the brake pedal jamming into the sensor mount and bending it, and it really bent it way out of reach just like last time and I had to bend it back again with pliers. So, the bottom line is that when replacing the actuator, you either have to be really careful to move the sensor out of the way or watch the brake pedal position, or prepare to bend it back when you're done. Working with a mirror makes it almost impossible not to bend the sheet metal on accident, but if you push the seat back and lie on your back to install the pin you can easily see the entire assembly.
     
    #44 Trafficat, Mar 10, 2025 at 10:14 PM
    Last edited: Mar 10, 2025 at 10:23 PM
    ASRDogman likes this.
  5. ChapmanF

    ChapmanF Senior Member

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    Which noise? The pumpy noise (like a whirr or joybuzzer)? A valvey noise (clicks and squirty sounds)?

    The booster (a small hydraulic chamber on the back of the master cylinder) is pretty much silent, so there isn't really a boosty noise to be heard.

    This is very good to know in case I ever have to do this job. (y)

    They did have a bad run of 2010 accumulators, but I have never been sure it was a design flaw. The defect information report made it sound more like there was one or more batch(es) of accumulators from one supplier where the bellows got fabricated slightly undersize. So the bellows could get shaken around inside the accumulator on rough roads, and develop cracks early.
     
    #45 ChapmanF, Mar 11, 2025 at 10:34 AM
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  6. Trafficat

    Trafficat Junior Member

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    Definitely a whirring/joybuzzer kind of noise
     
    #46 Trafficat, Mar 12, 2025 at 3:18 AM
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