Finished replacing booster/accumulator. Brake Bleed Next

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

  1. Trafficat

    Trafficat Junior Member

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    So I just replaced the booster and accumulator in my 2012 Prius, following youtube videos. I got my emptied brake fluid reservoir reinstalled and I'm about ready to start the bleed.

    First question I have for you, is should I be okay with any DOT3 or DOT4 brake fluid or is it really important to stick with the Toyota brand name brake fluid?

    For the next step, I am planning on using the authentic (from their website) Tactrix Openport 2.0 that I purchased a few months ago for this job, which I believe is compatible with Toyota Techstream. Unfortunately I think I need to pay like $79 for a 2 day license for Techstream, unless someone has a recommendation for a different software that I could keep for life. I kind of resent having to pay $79 for a 2 day license, especially if things go wrong and I end up having to do this multiple times. I have the brake warning lights, ABS, etc. on on the dash for my 2008 Gen 2 Prius too after someone changed the brakes on it when I was out of the country. I am guessing I need to use the scan tool for that car too when I'm done with this Gen 3 section. I'm hoping I can manage to get both cars done during the same 2 day window.

    My understanding is that using the software it will walk me through the steps for the brake bleed and the linear offset. I've never done a brake bleed before but after searching online, people seem to say that the Motive Products Power Bleeder is a great way to do one man brake bleeding. I'd rather not try and round up friends and want to make things easy on myself. So I'm thinking about trying to use that, or is there some reason why I actually need to be in the car pushing the brakes during the software walkthrough bleed process because of Prius being special here?



    .....

    As for the process of changing out the booster and the accumulator, Youtube was great. I found like 3 different videos and needed them all to get different perspectives on how to put in and take out the parts, plus searched random forums.

    It was mostly okay but I got tied up for a long time getting the nuts back on the rubbery bushings. The ones that look like little rubber 8 shot revolver cylinders. Ultimately I had to lift the wire harness above them up, giving me only a fraction of an inch more to work with, and also found out that the 10mm nuts are tapered on one side before the threads to make them easier to thread on. Undoing the bolt on the wiring harness only lets you move it slightly along the shaft slot but it makes a big difference.

    I lost the nuts down into the engine compartment and couldn't find them so bought some 10mm flange nuts that didn't have the taper which were nearly impossible to engage.

    I later found the original flange nuts with the taper and it made all the difference. Sticking them on with the box end of a wrench with a ratchet built in was also very helpful. Also, I didn't have flare nut wrenches and so I struggled with getting the brake lines back on at the end. Applying a strong normal force with the open ended wrench by pushing them like 45 degrees into the flare nut was necessary to get them to thread and not back out.
     
    #1 Trafficat, Feb 20, 2025
    Last edited: Feb 20, 2025
  2. MAX2

    MAX2 Active Member

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    First, you need to read the error codes to create the right path to eliminate them.

    Techstream will allow you to do the job quickly with the right cord, but do not forget that the 12V battery must be well charged.

    Many pumping failures occur precisely because of voltage drop.
     
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  3. Trafficat

    Trafficat Junior Member

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    That's a great thought on the 12V Battery. Car has set unused most of the last 3 months so battery charge is suspicious.
     
  4. Tombukt2

    Tombukt2 Senior Member

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    All of you need to be having a tender on the battery while you're hanging out with doors open lights on LEDs lid on the dash working on the car all of that Just makes good sense If you look at some tools like the AP200 I believe can bleed your brakes set the linear valve offset and the steering angle 63 bucks you don't have to dig around with any cables or any of that if thing is white if it ain't white it's not right in this situation this thing looks like an Apple product it's not black white and red that's incorrect AP200 look into it then you won't need anything else no cables you can keep this thing needs Android 12 or less I have it on an older blue tablet that all I use it for is car crap so on your phone running Android 15 it won't work. Mine bleeds the brakes and all that nonsense has the main you it walks you through like I guess you know you'd have to be pretty silly not to be able to follow along I guess I'll say pretty straightforward. Maybe go through and read it first and then attempt it whatever.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    With a 3 month hiatus for the battery I’d consider replacement beforehand. And have it on a smart charger for the brake bleed procedure.

    appreciate all the wrenching tips you’ve shared, and good luck with the bleed.

    (Maybe need to reword that last bit…)
     
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  6. Trafficat

    Trafficat Junior Member

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    Okay, so I don't have a battery tender but I filled my brake fluid reservoir and tried turning the car on.

    My plan was to just let it idle for a while so the hybrid battery would charge the 12V

    So far brake lights are solid on just with battery connected. Car seems to start, but the center screen is rebooting itself and even with the car off I am getting a lot of noise from the newly installed brake actuator system.

    Also the ICE is not kicking on as I would expect it to.

    I found a tutorial video on youtube for installing techstream in virtualbox since it isn't compatible apparently with my operating system.

    I got techstream to recognize my tactrix openport but I haven't yet tried to run the brake bleed operation with it or connect it to the car.

    Not sure if I need to manually adjust the actuator/sensor first to make sure it doesn't think the brake pedal is constantly depressed or if that will be something fixed in Techstream.

    Car battery is unplugged again while I just investigate for a while my next step
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Would there any reason not to run the Techstream brake bleed procedure (or comparable with alternate obd device) in advance, just as a test to verify it will complete?
     
  8. Trafficat

    Trafficat Junior Member

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    It appears that it will let me do the techstream brake bleed.

    upload_2025-2-27_15-2-45.png

    Techstream ECB says to do ECB-R first? ECB shows actuator replacement, but ECB-R only shows fluid replacement. The other options are greyed out. When I select it, it appears to begin to begin the bleed process.
    upload_2025-2-27_15-3-11.png

    However, I guess this is the sensor for the brake pedal being disengaged (stoplight). With the brake in a neutral position and the sensor extended out as far as possible by rotating the black box with the plug in it and pulling the other thing up, the white thing doesn't come close to hitting the metal thing above it.

    upload_2025-2-27_15-1-49.png

    So I guess in order to disengage the brake I need to adjust the push rod / yoke thing here.

    upload_2025-2-27_15-7-46.png

    I'm guessing that if I tried to run techstream prior to this adjustment, it might have some kind of issue because when it tells me to depress or lift the brake it will just see the brake is fully depressed all the time.
     
  9. ChapmanF

    ChapmanF Senior Member

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    I am deeply suspicious of the idea that the new actuator requires pushrod adjustment—that much pushrod adjustment—if the one you took out was properly meeting the stop light switch, and the car hasn't been monumentally reshaped in a crash.

    I would start by checking very carefully that the new actuator got installed seated fully down flat on the firewall, nothing pinched behind it, the old gasket came off with the old actuator, and so on.

    I would conclude only very reluctantly that so much pushrod adjustment was needed, if I could find no simpler explanation.
     
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  10. Trafficat

    Trafficat Junior Member

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    Hmm, well I can confirm that the old gasket came off with the old actuator
    upload_2025-2-27_15-30-55.png
    The one I took out was indeed activating the switch properly. However, online it seems that the box under the switch is green for other people and black for me, so it seems that maybe someone has already replaced this component, or there is color variation in the manufacturing.

    Everything seems snugged to me
    upload_2025-2-27_15-28-59.png

    upload_2025-2-27_15-30-3.png
    .
     
  11. Trafficat

    Trafficat Junior Member

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    I adjusted the push rod as far as it can go, and it still isn't close. I think maybe the stoplight bracket or the part that pushes the button got bent somehow. Operation Bending Sheetmetal commencing, I guess. Followed by drilling and adding a bolt to the button pusher if that doesn't give me enough movement.
     
    #11 Trafficat, Feb 28, 2025 at 3:09 PM
    Last edited: Feb 28, 2025 at 3:37 PM
  12. ChapmanF

    ChapmanF Senior Member

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    I've got a bad feeling about this....

    I wonder if something is up with the replacement actuator, limited range of pushrod motion or something.

    Did you get a chance to compare how far the pushrod projected from the old and replacement units?
     
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  13. Trafficat

    Trafficat Junior Member

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    I unfortunately didn't really measure things before I put the new one in.

    I completed "Operation Bending Sheetmetal" and now the brake light works properly.
    upload_2025-2-28_12-35-12.png


    I guess I'll hope for the best during the next step, and hopefully my replacement actuator isn't problematic. I think it was refurbished.
     
  14. Trafficat

    Trafficat Junior Member

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    Car needed a boost from a jumper battery to start up properly. Now that brake is disengaged, engine also started. I'm going to let it run for a while to hopefully rejuvenate the 12V battery a bit before I proceed with the bleed.