8
5. Inspectallair line fittingsandplugs for corrosion.Clean
allold threadsealant from thepipe threads.
Anycomponentexhibitingaconditiondescribedininspection
steps 2 to 5 should be discarded and replaced before
proceeding.
ASSEMBLY—REFER TO FIG. 9
1. Using a lubricant (Bendix Pc. No. 291126) lightly coat
allo-rings and theboresof the valvebody.
2. Installspringseat (9) ontotheinlet/exhaust valve (8)so
thatit covers therubber seatof the inlet/exhaustvalve.
Place the inlet/exhaust valve, large diameter first, into
theM-12™modulator'sbottom bore.
3. Installspring(10)overthebarreloftheinlet/exhaustvalve
(8)sothatone end ofthespringrestson the spring seat
(9).
4. Installtheo-rings(11812)intotherespectivegroovesof
the O.D. and l.D. of the exhaust assembly (13). Place
thelarge diameter ofthe exhaust assemblyagainstthe
spring (10) and compress the spring until the exhaust
assemblyenterstheboreofthebodyandthe o-ring (11)
seals against the wall of the bore.
5. Depress the exhaust assembly into the bore until it
exposes the groove for the snap ring (14). Install snap
ring (14) into its groove. Make sure it is fully seated.
6. Install o-ring (5) into its groove in the piston (6). Install
piston (6) into the M-12™modulator body. The piston
stem fits into the small hole in the center of the body.
7. Installo-ring(4)onto the protrusiononthebottomof the
M-12™modulatorsolenoidassembly.Installthesolenoid
assembly(2)ontothevalvebody.Thesolenoidassembly
will fit on the M-12™modulator body in any of four
orientations,90degreesapart.However,if clearance is
a problem, make sure the control port is not directly
above the valve's supply port, which will be nipple
mounted to a reservoir. Secure the solenoid assembly
to the valve body with the four 1/2" bolts. Torque the
bolts to 120 150 in. Ibs.
8. Install gasket (7) onto the EC-12™controller. Install the
EC-12™controller (1) as shown in Figure 9 by plugging
theelectricalconnectorfromthesolenoid assembly into
the socket in the bottom of the controller. Press in until
lock tab engages. Ensure engagement by pulling the
connectorlightly.Place the controlleronto the solenoid
assembly and secure with the four 1/2" bolts and lock
washers. Torque to 30 60 in. Ibs.
OPERATIONAL AND LEAKAGE TEST
1. Chockwheels.Fullychargeairbrakesystemandadjust
brakes.
2. Make several trailer brake applications and check for
promptapplication and releaseateach wheel.
3. Check for inlet valve o-ring leakage. With the trailer
service brakes released, coat the exhaust port and the
areaaround the retainingring with asoap solution.A1"
bubble in 3 seconds is permitted.
4. Checkforexhaustvalveleakage.Withthetrailerservice
brakes fully applied, coat the exhaust port with a soap
solution. A 1" bubble in 3 seconds is permitted. Coat
theoutside of themodulator body tocheck forsealring
leakage.No leakage ispermitted.
5. If leakage is excessive around the supply and exhaust
solenoids, replace the M-12™modulator. If excessive
leakage is detected where the solenoid assembly and
M-12™modulator body meet, replace the M-12™
modulator.Ifexcessiveleakageisdetectedattheexhaust
port,beforereplacing the M-12™modulatorperformthe
followingtest:
Place the vehicle in park by exhausting the air pressure
from the emergency side of the spring brake. Perform the
leakage check around the exhaust. If the air continues to
leakout the exhaustreplacethe M-12™modulator. If aleak
existsbetweentheemergencyandservicesidesofthespring
brake,theleakageattheexhaustwillceasewhenairpressure
is exhausted from the emergency side of the spring brake.
The air pressure will pass from the emergency side to the
servicesideofthechamber, out the service inlet and out the
M-12™modulatorexhaust.
ELECTRICAL TEST
If the status light remains on after the trailer brakes have
beenactuated,inspecttheEC-12™controllerforilluminated
LEDs. Each LED represents a specific area.
VOLT LED (red) High/Low Voltage
MOD LED (red) M-12™Modulator Failure
SNS1 LED (red) Wheel Sensor Failure
SNS2 LED (red) Wheel Sensor Failure
CONT LED (red) EC-12™Controller Failure
PWR LED (green) EC-12™Controller Power
RED LEDs INDICATE FAILURE
When the EC-12™controller senses a failure, the red LED
correspondingtothe failure modewillilluminate.Afailureis
stored in memory until the problem is repaired and the
EC-12™controller is reset. NOTE: Only the voltage LED
resets itself after the condition no longer exists.
