Brake Cylinder Replacement Questions

Discussion in 'Gen 3 Prius Technical Discussion' started by tyty, Jan 5, 2021.

  1. tyty

    tyty New Member

    Jan 4, 2021
    2010 Prius
    I would really love some insight into this. So my Gen 3 Prius developed this issue about 6 months ago whereupon braking past regeneration it begins to make a sort of quacking/barking noise and there is some vibration in the brake pedal, though there isn't really any effect on braking performance. I took it to Toyota and they said it was an issue with the master cylinder and that it would have to be replaced for about $3k. Now I've seen the process done on YouTube and it seems like something that I could do myself with little issue, but I'm new to the hybrid and Prius life, and researching this has left me with questions on a few topics that I figure you fine folks may be able to educate me on:

    1. On the Gen 3 the brake cylinder seems to go by multiple names when looking at the part for sale such as the actuator, accumulator, booster, etc. The terminology is unclear to me. If I'm understanding this correctly the cylinder is the part that is also called the actuator, and there is a separate part that has a different function that goes by the brake booster pump/accumulator. I'm just generally unclear of the separate parts and their exact functions and haven't been able to find any useful info on this topic.

    2. Of these two separate parts (?) the cylinder is the easy one to replace, and the pump is a pain in the nice person that requires you to take the whole damn car apart to loosen a few screws holding in the seemingly accessible part. Is this correct?

    3. As far as a proper diagnosis of the problem, does this noise indicate a cylinder failure from any anecdotal experience? Also, does this price point from the dealer seem to reflect a simple cylinder swap, or might there be more to the process such as the pump replacement? I can always take it back to the dealership for an opinion, and I may be cynical for thinking this, but could it be that they are trying to get me to buy into unnecessary services? I'll definitely be investing in techstream and a machine to run it as it will be needed in the bleeding process and it'll be helpful in future repairs down the line. Could that software help in diagnosing the correct problem?

    I feel like I have these general pieces of knowledge from the research I've done so far, but I just need help filling in the gaps and tying it all together. I'd like to become more proficient in hybrid and especially Prius repairs as I would love to make my car last by being able to take care of it myself and gain more knowledge of how it functions. Sorry if I come across as completely ignorant, a lot of these concepts are completely new to me and beyond my previous mechanical endeavors. And you never really know what you don't know! Before my Prius, I had an old Jeep liberty that was always having issues but the fix was always pretty straightforward. Thanks in advance for any knowledge you can share with me, it is truly appreciated!!
    marcoshenz likes this.