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Brake Fluid or Coolant Leak?

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Getting It Done, Feb 14, 2023.

  1. Getting It Done

    Getting It Done New Member

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    During a nasty cold snap and during my drive home, I started getting a Braking Power Low warning light on my dash telling me to stop in a safe place and to see the owner's manual. When I checked my brake fluid, it was really low. I added more fluid to about the middle of the low and the full line. Once I did that, the message did not appear after starting the car and driving to work. At the end of my work day, I noticed a puddle underneath the car closer to the back driver's side wheel. When I got home, I checked and noticed there was fluid on the panel under the car. See attached photos. Does anyone know what is under that panel that could be leaking? By the way, I haven't noticed a change in the way the brake pedal feels while driving. Also, my car is not pulling any codes. I also added some coolant when I added the brake fluid since that was low as well. I'm looking forward to anyone who can help me figure out what could be going on. I hope I can take the cover off in order to take a closer look, but thought I could try and get some guidance on what it could be going on before taking it to the dealer since I know they're going to charge me a boatload of money. My car is a 2017 Prius with 63,000 miles on it. IMG_2711.JPG IMG_2711.JPG IMG_2713.JPG IMG_2711.JPG IMG_2713.JPG IMG_2714.JPG
     
  2. JC91006

    JC91006 Senior Member

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    Since the fluid seems to be under the car, it could be something you pick up while driving. Not necessarily from your own car.

    Do you carry brake fluid and coolant with you when you leave the house?

    Low brake fluid can indicate the brake pads being low or it can indicate a leak. You should check that out.
     
  3. Doug McC

    Doug McC Active Member

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    I doubt brake pad wear at that low of mileage would be enough to cause low fluid levels. The difference between coolant and brake fluid should be fairly easy to detect simply by feel (significantly different viscosities and smell). From the appearance and location I would bet brake fluid.
    Either one leaking is worth a trip to the dealer, one for safety reasons (brakes fluid), the other for the damage to the inverter (coolant), seeing it is on the driver’s side. That inverter is expensive!
     
  4. FuelMiser

    FuelMiser Senior Member

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    All this tracks with a leak in the brake fluid reservoir (cracked?) or downstream from there. Isn't the brake fluid reservoir near the bulkhead on the driver's side, above the area of the puddle behind the driver's side front wheel? The Braking Power Low warning light is certainly tied to the fluid level in the reservoir--it was ON when you observed low fluid level and went OUT when you refilled. I wouldn't mess around with possible loss of braking. This needs to be checked for leaking starting at the reservoir and downstream from there. If you do suddenly lose braking, don't forget about the parking brake and even B mode to help slow down and avoid a collision.
     
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  5. Getting It Done

    Getting It Done New Member

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    Thank you all so much for responding. Do you know what is directly above that panel and if it comes off? I'd like to see if I can take a look before I bring it in.
     
  6. Doug McC

    Doug McC Active Member

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    My understanding is that all of the panels come off, but I don’t know exactly what is underneath that one exactly. It is pretty much directly under the brake fluid reservoir assembly.
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Brake fluid is hard on paint?
     
  8. ColoradoBoo

    ColoradoBoo Senior Member

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    Pray it's not your brake booster that needs replacing! (Big bucks, no whammies)
    There's a panel over the brake fluid container that has clips to allow access but you should be able to shine a line in there and see if you see anything leaking. My wife has the same car and, at last check, her brake pads were still around 6 mm...not even close to needing changing.
    Since you're in Colorado, I suggest taking it to a Christian Brother's automotive shop to have them inspect it. I've used them in the past for brake issues and always pleased with their professionalism and honesty and not trying to rip me off or up-sell stuff I don't need and they will use only Toyota OEM parts if you want.
     
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  9. Getting It Done

    Getting It Done New Member

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    It is definitely the brake fluid. I checked the brake fluid reservoir, which is now exactly on the low line when I had previously filled it between the low and middle lines. Since I can't take it anywhere today, I'm going to get it lifted and see if I can tell where it is coming from. Yes, ColoradoBoo, I hope it's not the brake booster too, and thanks for the suggestion for Christian Brother's automotive. They are pretty close. I appreciate all of your responses!
     
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