Brake Master Cylinder interchangeability

The brake actuator and master cylinder are one item. It is on the left.



Depending on what Toyota parts site you visit or which Toyota doc you are reading it is called a Brake Booster or Master Cylinder Assembly. It has the Skid Ecu inside and software in that ecu changes the part number. Every Prius v is different from any hatchback even in the same year. If the Prius v in 2014 has 17" wheels it has a different Master Cylinder Assembly than a 2014 Prius v with 16" tires. Get the wrong part number and it won't work. To complicate things they all have the same housing number embossed in the case which makes salvage yards think they are all compatible.*

The only sure way to get the proper part number is using the vehicle vin. A Toyota local or online dealer can look it up. Some Toyota online dealers websites can drill down based on model, year and trim. Or you can message them with your vin.

The (Accumulator) Brake Booster Pump or simply Pump Assembly on the right is more generic on gen3 hatchbacks and v's as it has no control built in. However these days it is rarely the problem.

The following captures from an online Toyota dealer represents parts needed for a 2013 v.




* If you wanted to risk installing a used Prius gen3 Master Cylinder you would need the donor car vin to verify its part number.

 

You might want to scan the service bulletins about Prius v brake issues to see if there was a replacement assembly mentioned with a part number starting with 04something. Those part numbers are 'kits', which Toyota sometimes creates to go with a service campaign, where the kit might include other stuff (like gaskets) that would normally have to be ordered separately. Also, oddly enough, the kit price is often better than the price under the original a la carte part number.

 

I would replace both which is what a dealer would do. However many replace the master cylinder assembly only.

If you are doing this diy and buying online, find a. online Toyota dealer with a good price and free shipping (they vary greatly) and send a message with your vin asking what part number(s) and gaskets.

I believe many reuse any clamps and the brake lines are flare fittings. Based on the diagrams it looks like the pump/accumulator comes with two bushings and collars used to mount it.


If you are planning diy, be prepared for the special flush and calibration procedure typically sequenced with Techstream. Many have issues on that step.