Gjohnson

Any ideas what is causing the noise that I periodically hear? I think I may just have to have Toyota or Lexus run the full bleed procedure when I get my oil changed.

jkittlesen

This is a joke ........right?
How are we to diag a noise you hear?

yyymmm31

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Where (at which step) did the bleeding process fail? From your description, it sounds that your brake system now works fine. Pragmatically, if your goal was to get rid of the priming sound from the actuator, you have reached your goal. The most critical bleeding step for replacing the brake actuator is bleeding the rear right side brake, which includes bleeding the brake actuator. if you have successfully completed bleeding the rear right side brake (in "Air Bleeding Utility" screen, select "Actuator has been removed" option, bypass bleeding front left and right brakes by pressing "Next" button twice, and then bleed rear right brake), you have also successfully bled the actuator. No further action is needed for bleeding the new actuator. The common cause for receiving the failed bleeding message "Air bleeding has failed. Verifying initial conditions:..." is that somehow the air pressure has built up back into the accumulator. Usually, you can re-run "Zero Down Accumulator Pressure" and "EBC Invalid (disable electronic control of brakes)" procedures again to get rid of this "Air bleeding has failed" screen.
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Gjohnson

The bleeding process is continually failing on the Right Rear side. The system states to loosen the bleeder valve and it will take roughly 40 seconds to purge the system. As soon as I click next on this screen, I get the failed error.

The first time I ran the full bleed procedure (Actuator removed) and the batter died. This procedure was working fine. It bleed the Right Rear side as stated and then moved on the Actuator pressure/de-pressure process. From what I recall, this step repeats 5 times. I had made it to 4 out of the 5 when the Low battery light came on. (Partly because I also had to make a quick run to the local auto parts store to buy more brake fluid.)

I have not ran the "Zero Down Accumulator Pressure and EBC Invalid (disable electronic control of brakes " procedures before but can give that a shot next time.

So, now I'm wondering if this is the cause. I Actuator removed bleed process was working fine up reinstalling the new Actuator, but there would not have been pressure in the lines. Now the process keeps failing, but maybe it's because the system is detecting pressure. I think it would make sense to run the Zero Down Accumulator pressure first before running the Actuator removed bleed process.

May be I missed this detail in one of your posts above, but does that makes sense?

Gjohnson

Sorry I missed this. I got the actuator for a site called OEM Vehicle Parts. Part ran $999.41 shipped to my door and is genuine Lexus part. Part was in a box inside a box. The original (smaller box) was from a local Lexus Dealership.

yyymmm31

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If you have successfully completed the rear right brake bleeding (in the "Air Bleeding Utility" screen and selected "Actuator has been removed" option) before your battery died, you have completed bleeding the new brake actuator. If that's the case, I don't think that you need to re-run the bleeding procedure for replacing the actuator. Instead, I recommend that you just run the rear left brake bleeding step since that was the only bleeding step that you didn't finish before your battery went dead. To just bleed the rear left brake, in the "Air Bleeding Utility Screen, select "Usual air bleeding" option instead of "Actuator has been removed" option. Then, in the next screen use the bleeding brake individually option to just bleed the rear left brake. Follow the instruction on the screen (run the "Reset Memory" and "Linear Valve Offset Calibration", etc.) to complete the bleeding procedure. Then, you will have completed the full brake bleeding process (although in two phases) for replacing the brake actuator. BTW, you mentioned that there was occasional noise in the brake system. I would think that it is most likely from the rear left brake line that you didn't finish the bleeding when your battery died (the possible cause is that there is air in the rear left brake line somewhere). After you bleed the rear left brake, most likely the noice will be gone after the air is purged out of the rear brake line.
***Edit: Very important: if you didn't finish/complete the rear right brake bleeding step before your battery died, you must re-run it to properly purge the air from the new actuator as well as the rear right brake line (run Zero Down Accumulator Pressure and EBC Invalid to release pressure from the accumulator again before bleeding the rear right brake - use the "Air Bleeding Utility" screen and select "Actuator has been removed" option to bleed the rear right brake line AND brake actuator).
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LS460Crown

Thanks for the great thread from all. I have the dreaded "brake malfunction" issue on my dash now, so I'm headed to Lexus next Monday. According to the dealer, I'm still under coverage for the enhanced warranty, please wish me luck.

Sami3

Did you solved your brake problem? Im looking for tips to solve my brake problems on my Rx 450h. Thats why im asking...

Best regards,

Sami

LS460Crown

Yes, a pack rat had gotten into my engine compartment and eaten through some wiring, so the dealership fixed it. So it drives like new again.

Sami3

Way to go!

Haitham600

I have the same issue with a prius that uses a very similar brake system. I am a mechanical engineer and i opened the old actuator, no one can fix such an accomulator even if have have a factory filled with equipment. This was made to be done and assembled once. Internal leaks as i studied the system are most apparantly related to pressure safety valve or what we call PSV. This is responsible of releasing the pressure that exceeds the accomulator rating. But when stuck open or leaky, it causes the valuable pressure to go back to the low pressur section in the system. Most likely through, is the accomulator bladder has a rupture. From expanding and contracting, once it has a rupture the pressurization air leaves to the oil part of the system. The pump works and builds up pressure in accomulator, but without compressable air on the other side, any small normal leak from any valve causes the pressure to drop quickly. But my problem with this is that the pump takes few sec to build up pressure but a PD pump should build it up from few turns if there is no compressible fluid in the system. The whole ABS quality of seals and the PSV are questionable. Toyota should make the PSV as a part of a replaceble accomulator, to solve 90% of the expensive replacements. Then it would be a matter of accomulator replacement, filling with instrument air to the right pressure, bleading the system and you are done. I just wont buy another one until the pump/motor fail again because the used one i put in there is also leaking similarly.

Sami3

Hi,

What errorcodes do you have on your Prius? Does everything work normally on the car like abs and safety systems?

/Sami