Toyota Transmission fuild in my brake fluid, is this bad?

Do not drive it or open the drivers doors. Have the reservoir suctioned out ASAP. Refill with brake fluid and repeat suction and refill. For ultimate peace of mind then have the system fully flushed; probably due anyway.

Good luck

 

If you have not driven it since the mix-up, I would DEFINITELY follow @fotomoto 's advice first. Take a taxi or whatever to get some DOT 3 brake fluid, at least one pint, preferably Toyota. Then, baste out as much as you can, refill, baste, refill, as many times as possible.

Note that there is a sort of basket inside the reservoir, not that deep, with just a narrow slot through which you can get a skinny tube down deeper. And then, yeah, get it towed to dealership, tell them the whole story, ask for a thorough brake fluid change.

FWIW, if a brake system is not leaking, and it shouldn't be: the brake fluid should NEVER need a top up. It's natural for the level to drop.

 

Adding mineral oil to a brake system will destroy the seals, and I would replace every last one of them before driving the car. Even a minute amount will cause the seals to swell and eventually fail.

Replaceing all the bits will be expensive!

Simon

 

If you have some basic diy tools, you can remove the reservoir pretty easily. Use a baster and take out as much as possible and remove the reservoir and clean it out with brake fluid.

Then take it to a garage a do a brake fluid flush out, make sure everything comes out.

 

Wow. Lucky, I hope. Only time will tell. But it sounds like you're ok. Just for your info. the master brake cylinder in the Prius is pretty expensive, due to its dual nature of regen/friction braking.

 

$65 what a deal

 

Yeah, go and sin no more. And say ten "invalid mode" procedures, as penance:

set parking brake
without foot on brake, press start button twice
foot on brake, shift to Neutral
press brake 8 times in 5 seconds
push park button
press brake 8 times in 5 seconds
foot on brake, shift to Neutral
press brake 8 times in 5 seconds
push park button
(car should exhibit blinking brake symbol, indicating in "invalid mode", for brake bleeding without techstream)

 

I would refuse to drive it till the master cylinder was rebuilt or replaced. Expensive? Yep, but I value my life. One droplet of oil that was missed could cause a brake failure.

Simon

 

$65, Wow . . . Any chance that your mechanic wants to move south for the Winter ?

 

I would really like to hear a follow up to this in a month. Everything I think I know about brake systems and mineral oil is that the gaskets will swell and you will lose your brakes, starting with the master cylinder. And it should happen quickly.

If your mechanic says OK... well.... he knows better than I do so I don't mean to scare you but I would really like to know if it's still fine after a month.