TSB BR001-07 Brake actuator noise

[galaxee]

lol, it is crazy, isn't it.

brake fluid down the armpit... fun!
to stop that from happening (with any fluid) take a shop rag and tie it around your forearm.

he's had all kinds of vehicle fluids spurted all over him and even into his face over the years... that's just part of the job.

[Patrick Wong]

Originally Posted by philmcneal

...lol bleeding prius brakes is downright wacky, although we skipped bleeding the other components though (such as the actuator bleeding, master cylinder bleeding and the stroke simulator bleeding) i just bled each wheel once (got brake fluid in my shirt and down my armpit! not cool!) till the fluid was about to retract then i close the bleeder to prevent air from getting in. Its werid though because you don't do the usual pump pump pump and then bleed each time but rather the computer pumps it and you just open the bleeder and get ready to close it when the pumping operation is complete. the person inside the car simply needs to hold the brake pedal (they warn you not to pump as you can activate the actuator and induce air in the system again) and activate the scantool (we used the panasonic toughbook techstream!) steps to acknowledge that bleeding is complete for that wheel and its time to move on to the next one.

wow bleeding prius brakes is a crazy animal!!! with a master tech sitting in my car took me 15 mins could have been less if I knew about closing the bleeder valve at the right timing(when the fluid is retracting)...

Hi Phil,

1. What does "fluid is retracting" mean?
2. Did you suck old brake fluid out of the reservoir (and replace with new) before starting the job?
3. How did the Panasonic Toughbook help the brake wheel cylinder bleed process? In other words, if that diagnostic tool was not available, how much more difficult would it have been to bleed the four wheel cylinders?
4. How much fluid did you use in bleeding the four wheels? Wouldn't that process have purged all old fluid out from the master cylinder?

Thanks.

[philmcneal]

1. basically you tell the scantool (ok im going to bleed the rear left wheel now) and as soon as you hit okay you should crack the bleeder. The stream of fluid should shoot out in a nice stream (probably no air) but then it starts getting less and less and that's when you should close the bleeder to prevent air from getting in. I guess the motor/acutator is doing the pump action because the person inside the car is not suppose to pump pump pump like normal cars bleeding procedure.

2. you can use a siringe kinda tool but i think I just added new fluid on top of what i had, i sucked it not too long ago (4 months) so i wasn't too concerned how new the fluid was, plus it was free so i'm not complaining!
3. The tech was in my car operating the panasonic toughbook, he was going through the menus and letting me know when to crack the bleeder (that's when he probably hit ok on the computer). And then from there on i just bleed all four wheels, as he kept inputting the sequence on the computer (he was high in the air so at times i missed my chance to bleed and he had to activate the menu again).

its impossible to bleed without the tool, you can't just pump the brakes because its just a stroke simulator, you can't command the lines to pump the way a traditional system linkage does. Hense the computer does the bleeding for you, you just have to crack the bleeder and be sure to close it when the fluid looks like its shooting less.

4. he filled it beyond the MAX level, by th etime i was don ewith four wheels it was below the MIN level, so i just top it off.

honestly out of practice it made no difference. However i do notice the actuator noise being more vibration like after using the brakes (even when its all regen) when accelerating from a turn or what not. But that sound was there before I bled the brakes, maybe now because of the process the noise got louder? Only apparent at low speeds, braking performance has not been affected.

[elitry]

anybody have any success getting this covered out of warranty window?

I have an '07 prius and bought it because i put miles and miles on my car and had to offset some of the environmental guilt. (already at 47k)

any suggestions, thoughts, or ideas are very welcome