Hydraulic Brake System; Meritor Wabco® Antilock Braking System - freightliner M2 Plus 2023 Manual

Brake Systems
exhaust-brake-enabled transmission ECM will usually
provide converter lockup in gears two through six.
Effective exhaust braking begins when the
transmission automatically downshifts into fifth gear
(62 mph or less). Once on, the Pacbrake exhaust
brake will control road speed and/or slow the vehicle
sufficiently that the transmission will automatically
downshift, if necessary, to Allison's preselect mode.
The preselect mode is normally assigned to second
gear; however, the transmission can be
reprogrammed by an Allison Transmission Distributor
to third or fourth gear, should the operator desire. If
additional retarding power is required before the
automatic downshifting occurs, you can select a
lower transmission gear on the Allison shift selector.

Hydraulic Brake System

Hydraulic Brake System, General
Information
The hydraulic brake system includes a power
booster, master cylinder, reservoir, hydraulic lines, a
brake rotor on each wheel hub, and a brake caliper
and pad assembly at each rotor.
The master cylinder controls braking power to the
front and rear brakes. The Bendix Hydro-Max®
power booster is attached to the rear of the master
cylinder and is connected to the power steering
system (which provides pressurized power steering
fluid). An electrical backup pump operates if there is
inadequate fluid flow from the power steering pump
to the power booster.
The brake system warning light illuminates if there is
a problem within the system. Bring the vehicle to a
safe stop and correct the problem before continuing
operation of the vehicle.
Hydraulic Brake System Operation
IMPORTANT: Make sure that the fluid level in
the master cylinder reservoirs is at the bottom of
the fill-neck. See Fig.
brake fluid, DOT 3, in the hydraulic brake
system.
IMPORTANT: Before driving the vehicle, secure
all loose items in the cab so that they do not
shift forward during a full brake application.
Make sure all passengers are wearing seat
belts.
11.7
11.6. Use only heavy-duty
A
08/03/2015
A. Open caps and check fluid level.
B. Fill to this level.
Fig. 11.6, Hydraulic Brake Fluid Reservoir (Bosch
reservoir shown, Bendix reservoir similar)
During normal brake stops, depress the brake pedal
until braking action slows down the vehicle. Increase
or decrease the pressure on the pedal so that the
vehicle comes to a smooth, safe stop. Apply the
parking brake if the vehicle is to be parked.
When parking a vehicle attached to a trailer, apply
the tractor parking brake. Chock the trailer tires
before disconnecting the vehicle from the trailer.
Meritor WABCO® Antilock
Braking System
The Meritor WABCO Antilock Braking System (ABS)
is an electronic wheel speed monitoring and control
system that works with the brake system. ABS
passively monitors vehicle wheel speed at all times,
and controls wheel speed during emergency stops or
wheel lock situations.
NOTICE
An accumulation of road salt, dirt, or debris on
the ABS tone wheels and sensors can cause the
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