Toyota Prius: friction brakes power-assisted?

Most conventional-drivetrain cars have power-assisted brakes, with the assist provided by intake manifold vacuum.

The Toyota Prius employs regenerative braking devices to recover the vehicle’s kinetic energy during braking events, but it also has traditional friction brakes for heavy deceleration and to hold the vehicle in position at a stop.

Note that since the Prius engine’s duty cycle is computer-controlled, it cannot necessarily be relied upon to have the engine running during braking events.

So…do the friction brakes on a Prius have power-assist? If so, are they reliant upon the engine’s intake manifold vacuum (provided by a reservoir), or are they assisted by an electrically-driven hydraulic pump (like the power steering)?

They have a separate hydraulic pump and reservoir. The reservoir seems to be able to provide 10 to 15 cycles minimum even with the pump disabled (not running).

ETA - I only have knowledge here of the 2004 Prius.

Pretty much the same on my 2010 model. I used to have a 2004 but last year I upgraded.

The regen system provides braking down to about 7 MPH or so IIRC, after which the friction brakes do the rest. A more forceful pedal application will engage the friction brakes at any speed.