Gen 2 rear brake bleeding no scan tool

Discussion in 'Gen 2 Prius Technical Discussion' started by Mr.Electric, Aug 20, 2020.

  1. Mr.Electric

    Mr.Electric Member

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    An excellent, highly skilled master tech told me this procedure. I have been waiting for a prius beat up enough to serve as a guinea pig for this questionable technique. I always had faith in the master tech who told me this trick but now I've seen it work with my own two eyes. I made a video of it. Haven't tried it on front brakes yet. The tech who told me about said it works on every toyota and lexus hybrid he ever tried for both front and back brakes. No scan tool no relay removal and pretty darn fast. I don't know if this would work for actuator replacement. Bleeding procedure shown towards the end of the video after wheel cylinder replacement.

     
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  2. ChapmanF

    ChapmanF Senior Member

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    Somebody tell me I didn't just watch a video of brake shoes and a wheel cylinder being replaced, followed by a caption saying "a shop would have charged well over $1,000 for this fix"....

    Or, tell me what shop that is ... are they hiring?
     
  3. Kenny94945

    Kenny94945 Active Member

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    Interesting.
    A "loophole" or scan tool/ software by pass?

    Apply 15 psi to master cylinder oil reseviour (using specialty brake tool).
    Depress brake pedal only one inch (and hold, lock in place)
    Open wheel cylinder bleeder.
    Bleed out a 1/4 pint of fluid.
    Close bleeder.
    Retain the brake pedal position - do not remove or release pressure.
    Check specialty tool psi.
    Repeat for the other three calipers.
    Release brake pedal.
    Check oil reseviour level.
    Test brake pedal pressure.
    Top off oil reseviour level.
    Install wheels.
    Test drive and activate ABS.
    Recheck oil reseviour level.

    So, does this "loop hole" work?
    Not only Gen 2, but all years?

    Again interesting.
     
  4. Moses Bruh

    Moses Bruh Member

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    interesting video, i remember someone saying to properly do a brake flush with techstream it takes like a full gallon of brake fluid, is that true?
     
  5. ChapmanF

    ChapmanF Senior Member

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    Well, I didn't see the video even claim you could repeat for all three calipers; it was about the rears.

    The hydraulic details for the fronts are different (and how they are different is kind of generation-specific, too).

    Ironically, the pressure bottle hardly saves you anything for the rears. So you can hold the brake pedal down and just let the pressure bottle pump fluid steadily out at the rears. That's exactly what happens if you use a Brake Rock and let the pump built into the car pump the fluid steadily out at the rears, which has usually had a non-Techstream procedure available, IIRC.

    The fronts are a different story, because (again, there are between-generation differences, I'll describe mostly Gen 3 here) there are two separate sets of hydraulic passages in the actuator to the front brakes, for normal operation and for fail-safe conditions, and when you are using the Techstream bleed procedure, it steps you through both front brakes twice. There's a click in between, and one time you have to pump the pedal like in your first car, and the other time the fluid pumps out just like with the rears. Any "loop hole" procedure for the fronts is going to leave one of those hydraulic paths unbled.

    But maybe the main observation is that many people who are seriously interested in maintaining a Prius long-term have already dug out an old laptop and spent $30 to $170 on a J2534 dongle for it, and are no longer tying themselves in knots looking for non-Techstream ways of doing stuff that Techstream makes easy.
     
  6. valde3

    valde3 Senior Member

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    Pressure bleeding brakes by pressuring brake fluid reservoir works for almost all cars. For gen 2 Prius it doesn't really make sense to use it on rear brakes as Techstream is faster and better. For front brakes it would be more useful especially if you don't have somebody to pump the pedal for you.
     
    #6 valde3, Aug 20, 2020
    Last edited: Aug 21, 2020
  7. Mr.Electric

    Mr.Electric Member

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    The video is incomplete but here is the intention:
    Bleed prius brakes without scantool. I will make another video that includes the front brakes.
    The Techstream is my go to for all toyota lexus work. Here is the issue. Many mechanics don't have a Techstream and shy away from bleeding brakes on a hybrid. A quality scantool like Snap-on or Autel will allow you to bleed brakes but tells you to refer to the manual regarding removing relays. This causes confusion and a reluctance to do the job. Call around to request brake fluid bleeding after caliper / wheel cylinder replacement on a prius. You will see the confusion/ reluctance to do this job reflected in the price.
     
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  8. Mr.Electric

    Mr.Electric Member

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    I made a new video that may better describe fthe procedure. The first video is replaced with this video.
     
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  9. ChapmanF

    ChapmanF Senior Member

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    Difficult to wave away those different hydraulic passages for the fronts though, that will never all be bled without some control of the valves that switch them.
     
  10. Mr.Electric

    Mr.Electric Member

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    Ok I messed with this procedure a bit more. Turns out the abs pump tries to maintain pressure so you can simply open the bleeder with pedal depressed to bleed both front and rear. This is an easy way to complete repairs after replacing a brake line , caliper or wheel cylinder.
     
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  11. ChapmanF

    ChapmanF Senior Member

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    It is also good to remember that there are two different sets of hydraulic passages serving the front brakes, which you cannot bleed both of without control of the valves that switch them.
     
  12. Aegean

    Aegean Active Member

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    I have completed this procedure with Techstream 4 or 5 times and used about 2 Quarts each time.
     
  13. valde3

    valde3 Senior Member

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    At the dealership it's about a liter or quart that's changed every time the brake fluid is changed. But that's just a change nobody is talking about flushing. Brake fluid is changed every other year here anyways.

    I have just changed almost a liter of brake fluid every other year with Techstream as it works for the dealership.

    Perhaps if your brake fluid is bad or it's not changed that often you would want to change more of it at the same time.
     
  14. Aegean

    Aegean Active Member

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    I change brake fluid every 30k miles so about 3 years. I use more fluid cause I bleed some extra from each wheel to be sure is clear and I do also the actuator bleeding procedure. I am sure someone can use less than 2 quarts but since an opened bottle has no shelf life I use the full second quart bottle thru the brake system.
     
  15. Mr.Electric

    Mr.Electric Member

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    Other people have tried the super easy way to bleed brakes shown in the video and report that it works. If you do some brake work like a caliper or line replacement the procedure is a fast way to complete the job.
     
  16. brochdknuckle

    brochdknuckle New Member

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    Thanks for the video on the Brake Bleed Prius with no Scan Tool. Just did my 2005 and seems like brakes are solid. I did brake job, when I got to the Shoes on back, pistons on cylinder popped out on one side, so placed back in but fluid came out during so just bleed that one line. Lost about 2oz during brake job, bleed out 6oz using your method. Never used brakes when I lost the 2oz, so feel air did not travel through line and ABS system pushed new fluid into cylinder.
     
  17. DutchPrius

    DutchPrius Member

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    I have one jammed rear wheel and after cleaning the entire assembly considering to replace the caliper. I don't trust myself with overhauling the caliper and did a change once on a different car (with less electronic and computer). Think I will try to do it myself this way, especially when more people have positive reaction doing this by themselves.
     
    #17 DutchPrius, Jan 4, 2021
    Last edited: Jan 4, 2021
  18. Mr.Electric

    Mr.Electric Member

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    Made another video featuring the quick no scantool bleed process ( at end of video )

     
  19. DutchPrius

    DutchPrius Member

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    I used the paper clip method after replacing the caliper, worked best for my Prius. I topped off the caliper with brake fluid as much as possible before installing and bleeding was done in a bit. Already had the brake error and had to use the paper clip in the OBD connector to reset and get rid of the error. Worked like a charm!

    Best regards, Nick

    Black 2007 Prius
     
  20. ChapmanF

    ChapmanF Senior Member

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    Anybody reading about a "paper clip method" will be well served to know that the reason brake ECU has behaviors programmed in for a jumper between Tc and CG is so that trouble codes can be easily read without a special tool. There is also a way to clear codes while the jumper's in place. But it's kind of unfortunate how many posters on PriusChat have heard only of using it to clear codes, and will often mention it right in the same post where they say they haven't got any way to learn what codes they have.

    As a general rule, it's a good idea to use the "method" to find out what the codes are before clearing them. You can often learn a lot about what's going on with the car that way.

    In some cases, like right after doing brake work, you might just assume what the codes probably are based on the work you just did, and simply clear them. Even in that case, you can sometimes gain an advantage by reading them first, especially if they turn out not to be exactly the ones you were expecting. That happens sometimes.
     
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