Brake Actuator and Bleed Brake System

get a second opinion and i would still drive it

 

Is the weird noise like a barking noise? You can't hear it when you brake lightly correct? Do you let you car sit for extended periods?

 

I bought a 2010 prius that was diagnosed from the dealer needing the master cylinder and both front wheel bearings for the super discount of 4500 dollars. I bought a master cylinder off ebay for 102 dollars and that was all she wrote for that problem. The deal is, the master cylinder for the front tires works like a normal master cylinder. You push the pedal and it pushes the pads against the rotor. So you are not going to get in some emergency situation where you cant stop your car unless the pedal gets spongy. Warning lights light up and buzzers beep but you can stop the car on the front brakes. The back are electric. and there is one more thing..a tube on it to make it feel like your pushing the brake when it regenerates. I used that tech software to bleed the master cylinder. It was much easier to do than the egr cleaning. Match the number off yours for your replacement. Candy from a baby. Yell with questions. Don't give up the car for a little issue like this. Really any mechanic could swap this part out and the replacement will work as good as the one you had. You just had a unlucky part.

 

Yikes.

 

here is what the number looks like. Its hard to see but match it up and you will be good.

 

They will be replacing the "brake actuator", and then bleeding the brake system.

It's part #1 (aka Brake Booster Pump Assembly) here I think:

Hydraulic System for 2015 Toyota Prius | Toyota Parts

Online price $696.98.

The attachment outlines complete removal/install of the system, of the which the brake actuator is a part. Normal brake bleeding can be done without Techstream software, but in this case it is mandatory.

 

For me the elephant in the room is the $3600 estimate: to replace a part you can buy for $696.98, and bleed the brakes. How many hours is 3 grand labour?

 

There goes the gas savings, after 46000 miles

 

No, be careful: the actuator is not the accumulator. In Gen 2 they were combined into one assembly, but in Gen 1 and Gen 3 they are separate. The OP's car is a Gen 3.

For even more confusion, the parts catalog calls the accumulator pump the "booster pump" (though it's part of the accumulator assembly or "booster pump assembly"), and that is entirely different from the thing called the "booster", which is not the accumulator (but rather an integral part of the master cylinder, in Gen 1 and Gen 3, and not present at all in Gen 2).

Gen 1 had the accumulator, actuator, and master-cylinder/booster separate (and the ECU inside the cabin). Gen 3 has the accumulator separate, but the actuator, master cylinder, booster, and ECU are combined into a single "brake booster assembly, with master cylinder", list price $2522 (though online dealers will sell discounted, $1652 here).

Note that there are different order numbers depending on whether you have the 17 inch wheels or not (or, just match the "mark" engraved on the unit, which you will notice is a five-digit-dash-five-digit thing just like an order number, but is not the same as the order number; it is shown as MARK in the descriptive text in the catalog for the different order numbers available).

-Chap

 

Did you look at my link? It's for 2015 Prius, and item one is called "actuator assembly"? Or am I missing something? I've no knowledge about it, just plugged in the year, fwiw.

Down the bottom of the page in your second link, it says "customers also bought" and shows "actuator assembly" for six something.

 

One more try to get everyone to consider used parts. On a wrecked car, the brakes are rarely affected and the system stays filled with brake fluid till someone opens the system. This unit does have a big electronic card in it because there is a big plug on it. I looked and there were multiple listings on ebay. You just need to get the number off yours and buy the same number. They usually give a warranty so if it doesn't work they will swap it out.

I replaced the master cylinder and filled it up with fluid.
bled the front wheels like you normally do with a regular car.
Hooked up tech stream software and bled the rear. You just open the valve since its electric.
then you bleed the cylinder on the master cylinder.
Jumper the odb2 connector to clear the code and check for errors. I haven't seen an error since, drove the car to work today. perfect!

Take advantage of the parts off the people who have wrecked their cars. Sure it could fail again same as the brand new one could fail again and the dealer will only cover that part for a certain amount of time and then its tough luck. If mine fails again, I really don't care cause it was so easy to swap out. Autozones new parts crap out all the time, in fact I had a Honda master cylinder fail twice. No big deal.

 

That seems to be a mislabeling in the McGeorge Toyota catalog that you linked to. I guess I can't fault you for that.

Compare the diagram in your link to the one on the third page of the "removal" Repair Manual excerpt that you also posted. You can see that the item in the McGeorge link is the same as the one at the bottom of the Repair Manual diagram, only the Repair Manual calls it "brake booster pump assembly with bracket", and the McGeorge link calls it, incorrectly, "actuator assembly".

Here is the same thing at parts.toyota.com, where it is correctly called "pump assembly, brake booster", same as in the manual.

How it gets mislabeled as the actuator is kind of a two-step mistake. The first step is that "booster pump assembly" truly is synonymous with "accumulator assembly" (it's the thing that stores pressure), and the second step is that confusion of the word accumulator with the word actuator is super common among people talking about Prius brakes.

Make no mistake: look back at that Repair Manual diagram, the item shown at the top of that diagram, as "brake booster with master cylinder assembly", is the big omnibus part that combines the master cylinder, booster, ECU, and actuator, all for the low, low price of $2522 (and, if you order now, with a free roll of shop towels for sopping up spilled brake fluid).

If the OP's dealer really meant 'actuator', that top item is the one that's needed. (If the OP's dealer said 'actuator' by mistake, meaning 'accumulator' just like the mistake in McGeorge's catalog, then it's possible the bottom item is what's needed, but in that case it would be hard to explain the high quoted price.)

Because there is so much confusion about nomenclature with the Prius brake system (and changes between generations), it does strike me as a really good idea to post and double check the codes retrieved and the technician's reasoning process, before being sure what part needs to be ordered.

-Chap

 

Chap, unlike me, you seem to know what you're talking about, lol.

Maybe @kamocasg can get a part number from the dealership.

 

Deciding who is right is pretty easy. one is saying master cylinder the other is saying booster. Booster makes power brakes and has no electronics thus no error codes. But no booster means no power brakes. I think someone would notice not having power brakes, and I don't think the dealer would have said it was safe to drive. The price of the part and installation tells you we are talking about a master cylinder. Just as a side note, the booster is located right below the master cylinder and has a red brake line running up to the master cylinder. It just has a motor to generate pressure. It would be easer to replace than the master cylinder as its held down with 3 bolts and one power connector. And I bet I could get it less than 100 bucks too

 

I know you mean well, but you're perpetuating one of the nomenclature problems here. In a Prius brake system, the "booster" and the "booster pump assembly" are two completely different things, in two completely different places. What you're talking about here is the "booster pump assembly", which is also safely called the "accumulator assembly" (avoiding any confusion with plain "booster").

The thing that's called plain "booster" is an integral part of the master cylinder assembly in Gen 1 and Gen 3. You can't get it separately, and it doesn't have any diagnostic codes of its own. It is not present at all in Gen 2. (For Gen 4, I haven't looked it up.)

The thing you're talking about here, the "booster pump assembly" or "accumulator assembly", is intensively monitored six ways from Sunday and does indeed have a bevy of related diagnostic codes.

-Chap

 

surprised this is still happening on a 2015, sounds like the same "extended warrantee" issue with the gen 2's my fix was also over three grand and it was covered by Toyota.. when I asked the trade in value of my 08 they said much less then the repair..

 

I have done a brake fluid flush on a 08 Prius , I made a mistake somewhere with cause the fluid valve to block and now no bleeding on or fluid coming out on brake, all light up and beeping ... any idea how to reset the valve to fix the issue .. much appreciated