Bleeding fluid flush

All you have to do is pump the brakes while the bleeder screw is open

 

I loosely followed @NutzAboutBolts video, except I did the brakes in the order proscribed in the (attached) Repair Manual excerpt. I didn't use a vacuum source, apart from using a syringe at the beginning to baste (old) fluid out of the reservoir.

The front brakes are pretty traditional, which makes them labourious and tricky to do. Watch the video carefully, in the split-screen they show the action of pumping the brakes, then quickly opening/closing the bleed screw.

The rears are easier, in that you can press the brake pedal, then open the bleed screw and let it pump.

To be on the safe side, I would stick to Toyota DOT3 fluid. The alternate you mention is probably fine, but who knows. I used two pints, fwiw.

Apologies, neglected to add the attachment earlier.

 

I HIGHLY recommend that you do not attempt to flush the brake fluid if you do not have access to Techstream or an equivalent aftermarket scan tool with the automated brake bleed function. If anyone errors are set while following the process described in the video, you will be left with an undriveable car and most shops will want an outrageous amount of money to diagnose and clear the codes.

 

@The Critic I respect your opinion; you may well be right, still the attachment I posted is an excerpt from the Repair Manual, specifically for brake bleed without Techstream, involves a chicken-dance. @NutzAboutBolts outlines the procedure in his video as well.

I followed it, no problems. I think the main thing is, you want to ensure you do not drop out of "invalid mode". The ways this can happen are outlined, and one of them is simply turning a wheel. So yeah, be careful.

 

From the 5 or 6 of these that I have done, after every brake flush, there will be several stored fault codes related to the process that have to be cleared. Usually it is a pressure-related fault code.

For that exact reason, I simply cannot recommend performing the brake flush without having access to the proper scan tool. The risk of an inoperable car is too high.

Perhaps when the car is in ECB invalid mode, some of the detection logic is ignored? I don't know...

 

I’m not sure what you did from those 5-6 brake bleed you’ve done to cause the brake issue, but I’ve been driving my Prius without issues.

The only thing I can see wrong is if you’re doing the brake bleed with the bleeder valve open and accidentally cause the vehicle to get out of the invalid mode. That will cause an issue. Other than that, it’s a closed system, you’re only messing with the bleeder valve opening and closing, and pumping the brakes to push the brake fluids out from the lines.

It’s basically a conventional brake bleed without techstream, except the rear brakes which is controlled electronically. If you can’t do that, I’d suggest bringing it to the dealership.

 

I have never done the brake flush using the ECB invalid mode.

I have always performed the brake flush using the guided function in Techstream or with the Maxisys Elite.

 

That is much easier if you have access to that.

 

Yeah the one sneaky one is turning a wheel, supposedly will kick you out of invalid mode.

I did the brake fluid change in invalid mode, 2.5 years back, no problems. Will do it again this fall.

 

My 2010 Prius got internal leak from the break actuator and now I have to replace it. Watching a few Youtube videos, it seems that it is highly recommended to get a nice scan tool to follow bleeding procedure as well as to complete 'linear solenoid valve calibration'. I am wondering a nice scan tool is really required for the replacement of break actuator to complete the calibration or your bleeding procedure in invalid mode should just work fine in this case as well?? Thank you~.

 

I doubt it. The @NutzAboutBolts video is for brake fluid replacement under normal circumstances. With actuator replacement you'll need Techstream or a high-end scan tool proven to work.

 

Yeah, we should avoid talking about any "bleeding procedure in invalid mode", because there isn't one; the procedure posted from the manual earlier in this four-year-old thread is specifically a fluid replacement procedure, though some early posts described it as "for brake bleed" by mistake.

The difference between brake bleeding and fluid replacement is bleeding needs to get air out. Replacement, if it goes right, puts new fluid (and no air) where old fluid was (and no air), and that you can do without a scan tool, by following the procedure given.

(If a fluid replacement doesn't go right, and air gets in, then you have a need to bleed situation, and you need a scan tool.)

After taking an actuator off and installing a new one, you will definitely have air in it, and you will have a need to bleed situation. You'll want a scan tool for that.

Ironically, what you don't need a scan tool for is the linear solenoid offset learning. There is a simple non-Techstream jumper-wire procedure for that if it's ever needed.

If I remember right, the long-form bleed procedure already includes learning the solenoid offset toward the end of the procedure. The only time you might still have C1345 (the code that says it needs to be done) after the full bleed procedure would be if something disturbed the automatic learning step at the end of the bleed.

 

Glad that I asked here before I jump onto the replacement of break actuator. I ordered OBD2 Cable with the Techstream software from Ebay. Hopefully, there is no complication. Thank both @Mendel Leisk and @ChapmanF for helpful comments.

 

On many cars, and probably Prius, if the brake fluid reservoir runs dry, it can bring air into the ABS system, and then you need to perform an ABS bleed, where you bleed the brakes while the ABS is being actuated by a scan tool.

Not sure if it’s a Prius requirement though.

 

ABS is only one of the interesting things going on inside a Prius brake actuator. There's more than a dozen valves in there, and your chances of getting all the air out without running the scan-tool-initiated program that wiggles all the valves for you in the necessary sequence is roughly nil. That's why the repair manual doesn't show any procedure for bleeding other than going through the automated program using a scan tool.

 

If one were to do a poor man's brake flush where they just excessively bleed all 4 wheels with no scan tool involved, what is the concern exactly?

 

It won’t help with air in the two components at the firewall?