BENDIX M-12-M-12R ANTILOCK MODULATOR Manual

®
Bendix M-12
® ™
SUPPLY
PORT
M-12
FIGURE 1 M-12 ™ AND M-12R
DESCRIPTION
The M-12 antilock modulator is a standard component in
™
Bendix antilock systems. It is comprised of two components:
solenoids, which rapidly apply and exhaust air during an
antilock stop, and a standard relay valve.
During normal, non-antilock operation, the M-12
serves as a relay valve that speeds the application and release
of the service brakes. If wheel lock up is impending, a antilock
controller commands the solenoids to modulate brake
chamber pressure on the axle(s) on which the system is
installed.
The M-12 modulator is offered in two configurations as
™
illustrated in figure 1. The M-12
attachment of an antilock controller, and it accepts electronic
commands from the controller through a four pin connector
(see Figure 1). The M-12R
mounting on a vehicle frame rail or cross member. It accepts
electronic commands from a remote mounted controller
through a wire harness assembly that has a four pin
connector at one end and a three pin connector at the other
(see Figure 1). The M-12
™
differ from each other only in that the M-12
& M-12R AntiLock Modulator
™
CONNECTOR
DELIVERY
PORTS
2 VERTICAL
2 HORIZONTAL
CONTROL
PORT
Modulator
™
™ MODULATORS
™
modulator permits direct
™
modulator is designed for remote
™
modulator and M-12R
™
™ modulator is
COVER
4 PIN
PLATE
DELIVERY
PORTS
4 VERTICAL
WIRE
HARNESS
3 PIN
CONNECTOR
designed for direct controller mounting while the M-12R
modulator uses a cover plate where the controller would
normally mount and a wire harness is attached to the
M-12R modulator in order to connect it to the antilock
™
controller. Two body styles are available; one with four
vertical delivery ports and another with two vertical and two
horizontal delivery ports.
modulator
The M-12 ™
to the service actuators it serves, and it can be nipple
mounted to a reservoir or secured to the frame rail.
The M-12 ™
M-12 ™ /M-12R
Air Connection
Supply (to reservoir)
Delivery (to brake actuator)
(can have 2 horizontal & 2
vertical deliveries or
4 vertical deliveries)
Control
(to rear service brake valve delivery)
The standard M-12
a 4 psi crack pressure. The internal components are
modulator
interchangeable with R-12
the same maintenance kit is used to service all.
M-12R Modulator
™
/M-12R ™ modulator is normally mounted close
modulator air connections are as follows:
™ Modulator
and M-12R modulator is offered with
™ ™
™ and R-14
SUPPLY
PORT
CONTROL
PORT
™
Embossed
Identification
SUP
DEL
CON
™ relay valves therefore,
1