Servicing The; Controller; Replacing The Ec-30T Controller; Overhaul Of The Relay Valve - BENDIX MC-30 TRAILER ABS CONTROLLER Manual

tubing, hose, fi ttings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifi cally for such applications and
systems.
9. Components with stripped threads or damaged
parts should be replaced rather than repaired. Do
not attempt repairs requiring machining or welding
unless specifi cally stated and approved by the
vehicle and component manufacturer.
10. Prior to returning the vehicle to service, make
certain all components and systems are restored
to their proper operating condition.
11. For vehicles with Antilock Traction Control (ATC),
the ATC function must be disabled (ATC indicator
lamp should be ON) prior to performing any vehicle
maintenance where one or more wheels on a drive
axle are lifted off the ground and moving.
SERVICING THE MC-30
™
CAUTION! All MC-30
replacement parts are initially defaulted to 4S/2M
side control and may need to be reconfi gured upon
installation. An incorrect ABS configuration may
cause fault indication or degraded ABS performance.
Before and after activating a self-confi guration, always
determine the current ABS confi guration by monitoring
the diagnostic LEDs at power-up or by activating blink
code diagnostics.
Prior to performing service to the MC-30
always perform the following steps:
1. Turn power off.
2. Drain the air pressure from all reservoirs.
3. Remove as much contamination as possible prior to
disconnecting electrical connections and air lines.
™
4. Note the MC-30 controller assembly mounting position
on the vehicle.
REMOVING THE MC-30
M-30T ™ MODULATOR-VALVE
1. Disconnect the 30-pin ECU connector and the 3-pin
modulator connector from the MC-30
2. Remove all air lines connected to the unit.
3. Remove the MC-30
vehicle by removing the mounting bracket nuts or by
rotating the entire assembly counterclockwise from the
tank mount.
REPLACING THE EC-30T
In some cases, only the EC-30T
be replaced. See Figure 18. If suffi cient clearance is
available, the EC-30T ™
the MC-30 ™ controller assembly is still mounted to the
frame or tank. If the MC-30
the vehicle, it may be lightly clamped in a bench vise
during disassembly. However, over-clamping will result
in damage, leakage, and/or malfunction. If a vise is to be
used, position the MC-30
the fl at area of the ECU bracket.
1. Disconnect the 30-pin ECU connector and the 3-pin
modulator connector from the MC-30
™

CONTROLLER

™
and EC-30T controller service
™ controller,
™ CONTROLLER OR
™
controller.
™ controller assembly from the
™
CONTROLLER
™ controller will need to
controller can be removed while
™ controller is removed from
™ controller so the jaws bear on
™ controller.
2. Remove the MC-30
necessary.
™
3. Note the EC-30T controller position on the MC-30
controller assembly and remove the four ECU mounting
bolts. The original bolts can be reused for installation
if they are in good condition. If replacement bolts are
needed, grade 5 bolts or stronger are required.
4. Reinstall the new EC-30T
mounting orientation. Torque the mounting bolts to
98 in. Ibs. Over-tightening the ECU bolts can cause
damage to the EC-30T
5. The new EC-30T ™ controller may need to be reconfi gured
for proper operation. Leakage and Operational Tests
must be performed before returning the vehicle to
service.

OVERHAUL OF THE RELAY VALVE

Several maintenance kits are available when a relay
valve overhaul is necessary due to excessive leakage or
contamination of the valve. See Figure 18. Instructions
for the overhaul are provided in the replacement service
kit. For more information on Bendix valve maintenance
kits, contact Bendix or refer to your local authorized Bendix
dealer.
CAUTION: There are no serviceable parts in the solenoid
assembly portion of the modulator-valve and it should never
be disassembled. If troubleshooting indicates failures in
the solenoid function, replace the entire M-30T
valve.
™
MC-12 MODULATOR / MCE-12 SERVICE
REPLACEMENT
™
The MC-30 controller is designed to be the service
replacement part for the MC-12
When EC-12, M-12 ™ antilock modulator or ME-12 service
replacement parts are required, the entire MC-12
assembly and pigtail harness must be replaced by an
™
MC-30 controller assembly and pigtail harness. When
replacing an MCE-12, the integral emergency function
(EV-2) must be replaced by a DC-4 and TR-3
combination. See Figure 19 for plumbing details.
MC-30 ™ controller kits are available to replace all
™
MC-12 modulator assemblies and harnesses. For more
information, contact Bendix or refer to your local authorized
Bendix dealer.
CAUTION: The tank-mount MC-30
be mounted on a frame or crossmember using the ECU
bracket holes.
1. Disconnect the power connector and wheel speed
sensors from the MC-12
2. Remove all air lines connected to the unit.
™
3. Remove the MC-12
from the vehicle by removing the mounting bracket nuts
or by rotating the entire assembly counterclockwise
from the tank nipple mount.
4. Install the new pigtail, starting at the power connector
and properly securing the harness every 18 inches to
the ECU location.
5. Next, refer to the Reinstallation of the MC-30
™
or M-30T modulator-valve section.
™
controller from the vehicle if
™ controller in the original
™
controller.
™ modulator-
™
modulator product.
™ modulator
™
controller must not
™ modulator pigtail harness.
modulator assembly and pigtail
™
controller
™
™
valve
17