Rear Brake Bleed help after ABS Actuator replacement w/ techstream

Okay so when you're bleeding the front brakes you have the relays out the two blue ones want the top of the fuse box one at the bottom. You start on the left side of the front your person pumps the brakes and then holds the pedal down you release fitting. Fluid comes out you close up they pump again hold down release the fluid so on and so forth then you do the right front this is just pumping out fluid at this point more than likely. Then you're supposed to put the front relays back in and you go to the back left when you go to the back left with the relays in your person is going to pump up the brakes if they want to then hold them down You're going to crack the fitting fluids going to start to come out and you should hear the pump start to run and then the stream of fluid get a lot stronger and it'll shoot you in the face if you're not careful You get a squirt then you close it your person in the car can pump up again hold down You can crack hear the pump come on fluids ripping. Go to the other side rear do the same thing now with the relays in still Go back to the front of the car left side first have your buddy pump up and hold down now crack the left front and it should work similar to the back You should hear the pump come on force fluid through out of the fitting about mid squirt you stop it pump up again repeat the process still seeing nowhere they're probably isn't any then you go back to the left side same thing that should have you relieved of all air except for what we believe to be in or behind the various valves in the actuator that hasn't open yet because nothing has commanded the valve to open. That's what you're doing with tech. When I did this exact process with my '09 I needed to do nothing else still today that 09 has only been bled by this method and I own the Toyota software now I just haven't bothered to bleed the '09's brakes because they work perfectly no lights are on and we're done with that job.

 

Once I bled the front with the relays out like a regular old car with the person sitting in the seat actually you don't really have to do the pumping and all that craziness if you don't want to. Fill the front reservoir full of brake fluid over the full line if you like now crack the front left fitting on the caliper lay there on a blanket and watch that fitting You can even strategically place a glass under the drips coming out of that fitting and it will fill the glass drip drip drip drip drip. If you lay there and watch that you will see the air bubble out of the line all by itself you can see the foam kind of appear at the little hole on the fitting on the caliper and then that foam will start to disappear and drop off into the glass with the drips of brake fluid and the phone will be gone that was your air now you have solid dripage coming out of that fitting with no air in the drips You can see that by looking in the glass as the drops dropping the glass that is gravity bleeding That's because the reservoir is higher than the calipers in the wheel cylinders and it naturally wants to flow which way? Downhill like poop flows. Now that'll be a bunch of people along in a minute telling you why this is not that and all this but it works I've been doing this on other vehicles for 40 years never had a brake failure in my life until I owned an '09 Prius in 2023 and been driving since 69.

 

Could it be that the Gen 2 Prius is somehow different from the other cars you've been doing this procedure for the last 40 years?

 

Yes it's a fact that it is and that's not indispute in any sort of way at all. I'm just saying that this is what happened with a couple of cars here. I was able to bleed the brakes just as stated somebody else has done it too Not trying to make anything wrong or right or trying to make it so I can step on the brakes and stop the car and it feel like it did 3 weeks ago or what have you but actually in reality as far as ABS brakes and accumulator and pump assemblies go the Prius is like some of the early Bosch ABS systems that were on some forms of BMWs and other vehicles I remember when brake pumps were $5,000 on some cars basically worked very similarly. This was before computers were advanced enough to step in and help with brake bleeding and what have you. Everything evolves. No question about that It's just that in '04 to '09 maybe Toyota wasn't committed completely to what they are committed to now. Realizing this car has built-in safety battery backup so on and so forth to make sure that the brakes will apply and almost any condition no matter what's happening probably even if you run out of fluid just kidding. So I think having an accident causing a 10-car pile up and getting crushed by eight trucks and all this kind of stuff is probably a little overthought out.

 

Yeah, that is just kidding, because the fluid has to be there to apply the brakes. And it has to not have air bubbles in it. And some of those air bubbles can be behind those valves in the actuator that are solid closed the whole time you're doing your "look ma, no scan tool!" bleed.

Valves can be a little like facts, stubborn things that don't quite go away just because you're not thinking about them.

 

I guess so far I've had the exact opposite problem once the relays are back in from doing the front and I think in between that you do the actuator pump the thing 30 times and 30 seconds and whatever it is and then what is it you put the relays back in and you go to the back the minute those relays go back in the back should be capable of squirting fluid even if you have a lot of air the fluid will initially squirt out what was in the line then you'll hit the air close the fitting have your friend pump up hold down again and once maybe twice of that and fluid should start to come and then it will squirt out directly You need to close up and go check your reservoir go back and do that side one more time and then go to the other side. But I get what you're saying so it sounds like the pump isn't running when you have the relays in and you're supposed to be at the back of the car? That is kind of weird. But even without tech connected with relays and everything in and you go to the back of the car you should have automatic squirting happening it'll empty the reservoir if you're not careful.

 

It might have looked mechanically similar, but as you say no computers, so that changes everything.

That's the way it works but, do you have any brake DTCs? You need to clear any brake codes as the system can disable each of the rear lines independently of each other if it suspects a fault like a leak in one of the lines.

 

Deer in the bleeding process with tech if you know in the text it will tell you that you will be getting codes while you're doing the bleeding you will need to clear them when you're finished I believe it talks about this on the screen taking the relays out and whatnot will net you codes.