2001 TOYOTA PRIUS Service Repair Manual

CHASSIS ± SUSPENSION AND AXLES
182CH36
12-point Nut
Double-Row Angular
Ball Bearing
182CH37
ABS Speed Sensor
Double-Row
Angular Ball
Bearing99
AXLES
1. Front Axle

The front axle use a double-row angular ball bearing which offers low rolling resistance.

A lock nut (12-point) has been adopted and staked for tightening the axle hub in order to ensure the tighten-
ing performance. This nut cannot be reused.
2. Rear Axle

The rear axle use a double-row angular ball
bearing which offers low rolling resistance.

ABS speed sensor and rotor are built in the axle
bearing.

CHASSIS ± BRAKES
182CH38
100
BRAKES
DESCRIPTION
The front brakes use ventilated disc brakes and the rear brakes use leading-trailing drum brakes.
To adjust the clearance between the shoes and drum, the rear drum brakes uses the incremental type hy-
draulic auto adjuster.
On the Prius uses a pedal type parking brake that is released by pressing the pedal further.
A hydraulic brake booster in which the master cylinder and booster are integrated has been adopted.
The Prius has adopted the ABS with EBD (Electronic Brake force Distribution) as a standard equipment.
A regenerative brake system, which uses the MG2 that is used for driving the vehicle as a generator to
efficiently convert the energy that is created during braking has been adopted. This system enables to col-
lect more driving energy by having the control to cooperate the hydraulic brake and the regenerative brake.

CHASSIS ± BRAKES
182CH39
182CH40
101

Specifications 
Master CylinderTypeSingleMaster CylinderDiameter mm (in.)22.22 (0.87)
Brake Booster TypeHydraulic
TypeVentilated Disc
Front BrakeCaliper TypePE54Front BrakeWheel Cylinder Dia. mm (in.)54.0 (2.13)
Rotor Size (D x T)* mm (in.)255 x 22 (10.04 x 0.87)
TypeLeading-Trailing Drum
Rear BrakeWheel Cylinder Dia. mm (in.)20.64 (0.81)
Drum Inner Dia. mm (in.)200 (7.87)
Brake Control Valve TypeP & B Valve
TypeDrum
Parking BrakeSize mm (in.)200 (7.87)g
Lever TypePedal
ABS with EBDSTD
*: D: Outer Diameter, T: Thickness
FRONT BRAKE
The PE54 type brake calipers and ventilated disc
rotor have been adopted. These brake calipers are
lightweight and compact to realize excellent brake
performance.
REAR BRAKE
General
The leading-trailing type drum brakes using
drums with a 200 mm (7.87 in.) inner diameter
have been adopted.
A hydraulic system that adjusts the clearance
between the shoes and the drum has been
adopted.

CHASSIS ± BRAKES
165CH33
Wheel Cylinder
Adjusting Bolt
Shoe
Strut
Auto
Adjust
Lever
Spring
A
C D
B
182CH41
PawlPawl SpringRelease
Intermediate
Lever
Sector
Parking Brake
Cable 102
Incremental Type Hydraulic Auto Adjuster
Ordinarily, when the rear brakes are applied, the
shoes expand until they come in contact with the
inner surface of the drum.
While the auto adjust lever remains in contact
with point A of the strut, the spring force causes
the auto adjust lever to rotate in direction C, with
adjust lever point B as the fulcrum. At this time,
if the shoe clearance exceeds a predetermined
amount, the tip of the auto adjust lever rotates the
adjusting bolt in direction D by 1 tooth, causing
the strut to move for a predetermined amount to-
wards the direction that expands the shoes. As a
result, by pushing and expanding the initial posi-
tion of the shoes, an appropriate amount of clear-
ance is maintained between the shoes and the
drum.
PARKING BRAKE
1. General
On the Prius uses a pedal type parking brake that is released by pressing the pedal further.
2. Construction
A pedal type parking brake pedal consists mainly
of a parking brake pedal, sector, pawl, release in-
termediate lever, pawl spring and pedal return
spring.
The parking brake pedal and sector are integrated,
and parking brake cable is attached to the parking
brake pedal.
The pawl and the release intermediate lever are
linked by the pawl spring and operate together
along with the movement of the pedal.

CHASSIS ± BRAKES
182CH42While Pressing Locked StateStroke
Reaction Force
of Parking
Brake Cable
182CH43
Press Again During Pedal Return Lift Portion of
Parking Brake Pedal103
3. Operation
During Applying
Pressing the parking brake pedal causes the sector's rachet to engage with the pawl. Then, when the pressure
on the brake pedal is released, the reaction force of the parking brake cable and the force of the pedal return
spring cause the pawl and sector, which remain engaged, to return (only for the stroke). As the result, the
parking brake becomes locked.
At this time, because the relative installed position of the pawl spring changes, the force of the pawl spring
that was applied to the intermediate release lever switches its direction and now pushes the intermediate
release lever down.
During Releasing
When the parking brake pedal is pressed again, as the reaction force of the parking brake cable and the force
of the pedal return spring will not be applied to the pawl, the action of the pawl spring causes the pawl to
lift. As a result, the pawl is released from the sector's ratchet.
Next, when the parking brake pedal returns to its initial point, the lift portion of the parking brake pedal
causes the intermediate release lever to lift. The pawl is then pushed down by the force of the pawl spring
and returns to its initial state.