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Brake Pump noise???

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Alex Young, Jul 16, 2018.

  1. Alex Young

    Alex Young Junior Member

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    Hi All,

    It's been a while since I have posted on here. I have a 2008 prius with 193,000 miles on it. I purchased it about 4 or 5 years ago with 117k miles on it. It has always made a strange noise, almost sounds like a faint honking noise when the brake pedal is depressed and the car is at a complete stop. I think at some point I had seen a few threads where this may have something to do with the hybrid system and brake system, some kind of vaccum pump or pressure pump, I don't know. However the sound used to be less noisy and a lot less frequent. However in the last few thousand miles it's more frequent. When I have passengers with me or I am in line at a drive thru it's a distraction. I am mostly concerned to know if this is a possible safety issue. Can anyone please advise? I have a video from this morning after I stopped and parked at work, you can hear the noise. That is coming from under the hood with the brakes depressed:



    Thanks!
     
  2. bisco

    bisco cookie crumbler

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    the honking is not a problem. if the dash lights up, you will need to replace the actuator.
     
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  3. Alex Young

    Alex Young Junior Member

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    Thank You!
     
  4. JC91006

    JC91006 Senior Member

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    I think you should have that checked, hopefully a brake fluid flush can solve that issue. But I wouldn't wait for complete failure before looking into it
     
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  5. Alex Young

    Alex Young Junior Member

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    Yes, I agree. I just dropped it off at Toyota about 30 minutes ago to get an oil change and asked them to analyze the noise and just confirm that it's a noisy actuator and not something that needs fixed. Thanks!
     
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  6. Alex Young

    Alex Young Junior Member

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    A local toyota service department informed me it did sound like the actuator but that it was functioning fine and just to watch for any service lights on the dash.
     
  7. JC91006

    JC91006 Senior Member

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    Since this is a safety item that you must fix one day or you'll have a tough time selling it. I would recommend just fixing it now
     
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  8. Alex Young

    Alex Young Junior Member

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    So I called my local toyota dealer to check up on this and found out a couple of interesting things. First being that there was a recall on this for 10 years / 150,000 miles. Unfortunately for me my 10 year window is about 9 months past and I am at 194,000 miles too. I was told they have to remove the inverter, so it's about 8 hours labor and the part itself is $1700 and change. So that means a bill of $2800 to repair the car. Doesn't seem like a good investment... I am going to have to consider dumping the car even though I just put a new $3200 battery pack from the same dealer last year.
     
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  9. JC91006

    JC91006 Senior Member

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    Try to buy a used part on eBay and have a private shop install. Many people have gone this route
     
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  10. johnjohnchu

    johnjohnchu Active Member

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    Toyota definitely will not replace the actuator under recall/warranty if there is no dashboard warning light. It is normal for the actuator to run briefly after some braking action. However, if it continuously to run frequently even without prior braking action on your part, then there is a leak in the actuator and should be replaced.
     
    #10 johnjohnchu, Aug 30, 2018
    Last edited: Aug 30, 2018
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  11. ChapmanF

    ChapmanF Senior Member

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    Well, the pump for the accumulator is what runs briefly after some braking action.

    It happens that in Gen 2, the accumulator and actuator are combined in the same catalog part, so mixing up the terms doesn't do much harm in Gen 2 ... but it also doesn't help people cement a good understanding of what's what.

    I might suggest that the part in there now isn't all worn out quite yet (even to the point of warning lights), and any replacement you put in starts wearing out the moment you do, so why not see how much longer you get with this one before putting in that effort? If downtime is a concern, you could start watching for a good deal on a used one and have it on hand. If the part is still on your shelf when you're done with the car for some other reason, you've saved the labor, and somebody might buy it.

    -Chap
     
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  12. johnjohnchu

    johnjohnchu Active Member

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    FYI: Toyota Actuator assembly comes with its uniquely paired actuator resistor. See attached photos. DSCN4684.JPG DSCN4670.JPG DSCN4684.JPG DSCN4670.JPG resistor.JPG
     

    Attached Files:

  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I agree.
    I agree with this.

    You've already received good advice not to worry about the honking sound, until you actually see the ABS/VSC/BRAKE/((!)) warning lights appear. So why would you want to dump the car after having spent $3K on a new battery? Just drive the car and relax, as long as no lights are on.

    Then, if/when those warning lights come on, have a used brake actuator installed. The labor effort will be costly but at least you can save by buying a used part.

    The honking sound will tend to occur more at high altitudes. My 2004 had that occur from time to time. The sound comes, then it goes. The 2007 did not have that particular issue, but I had to have the skid control ECU and the brake pedal stroke sensor replaced under warranty.

    It is true that a new actuator comes with a matched resistor, but I would not worry about that. When the time comes that the actuator kicks the bucket, just install a used actuator and you will be good.
     
    #13 Patrick Wong, Aug 31, 2018
    Last edited: Aug 31, 2018
  14. srellim234

    srellim234 Senior Member

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    Thanks for that reference regarding altitude. We were a little worried as we got a strange sound (more like a squeak) out of it when we were in Denver a couple of weeks ago. We haven't heard it again since we returned to lower altitudes.
     
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  15. Alex Young

    Alex Young Junior Member

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    Just an update for anyone who finds this thread. I took my car several months back to a local mechanic that charges $83 per hour for true number of hours, not book hours. I had him review the vehicle, but with no lights on he refused to replace the actuator. He is a very good mechanic and didn't charge me to review the car. I got the general idea I was going to be between $1,800 and $2,000 to replace with a new part from Toyota. He refused to use a used brake part such as this, probably for liability reasons. I couldn't find a reputable mechanic that would put on a used part. All that being said the dash lights just came on yesterday and this local mechanic is booked 2+ weeks out. I have 4 young children and have no interest in driving them around in a car with brake lights on for 2 weeks. I negotiated with my local toyota dealer and they have agreed to replace the part out the door for $2,500. The convenience of getting it done now, instead of 2 weeks from now and the fact that a toyota mechanic who is familiar with these cars makes the $500 acceptable for me personally, even though I woudl have preferred to save the $500. Hope this is useful information for someone in the future. Thanks!
     
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  16. VFerdman

    VFerdman Senior Member

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    My '07 has the "honking", which gets more prominent in the cold weather (almost absent in the summer).

    It was mentioned that a brake fluid flush may address this issue. Is that a confirmed remedy? I bought this car in July 2017 with 175K miles on it and so far I have not had to do much to it at all in terms of repairs. How does a brake fluid flush work on a Prius? I have done it many times on conventional cars with ABS using a Motive Products power bleeder. I have also done it using the old fashioned two person method and vacuum method. I am well familiar with how to flush the brake fluid on a non-hybrid. However on a Prius I am ignorant. If anyone can point me to a good how-to, I'd appreciate it. The car's brakes work fine and I have no complaints except for the "honking" sound that really concerns me. If I can prolong the life of the expensive brake actuator by a fluid flush, I would love to do it.
     
  17. dolj

    dolj Senior Member

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    Unless you have Techstream or a Denso handheld intelligent tester, like the Toyota techs use, I don't think it is possible to do a flush of the brake actuator. It also seems that some Toyota places do not recommend flushing of the brake actuator.

    Not sure if just flushing new fluid through to the "four corners" will address the "honking" issue.
     
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  18. VFerdman

    VFerdman Senior Member

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    I do have a mini-VCI cable, but have not set up Techstream yet. Getting by with Android apps and a bluetooth dongle thus far. However I would be motivated to set up Techstream if I knew it would help with the barking brakes. I have read a bunch of stuff where it says that flushing the brake accumulator (part of the actuator/accumulator on Gen 2) is not a good idea and sometimes can cause its demise prematurely. So I think I will stick with the old "do nothing" for now. The barking is not very bad and does not seem to be getting worse. Like I said, it's usually not present in the warm weather, so it's only there part of the year. I'll just keep my fingers crossed and hope I do not need an expensive actuator replacement anytime soon.

    Having said all that, is it still a good idea to flush the four corners to renew the fluid in business ends of the system, actuator notwithstanding? I usually do that on conventional cars with some regularity, but on the Prius I am more inclined to leave it well enough alone.
     
  19. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I don't know how you would flush fluid at the wheel calipers/cylinders without passing fluid through the actuator.
     
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  20. VFerdman

    VFerdman Senior Member

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    Fair enough. I guess I do not understand the system enough to ponder that one...