7
8. Use only genuine Bendix®replacement parts,
components and kits. Replacement hardware,
tubing, hose, fittings, etc. must be of equivalent
size, type and strength as original equipment and
be designed specifically 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 specifically 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.
PREVENTIVE MAINTENANCE
GENERAL
Performthetestsandinspectionspresentedattheprescribed
intervals. If the modulator fails to function as described, or
leakageisexcessive,itshouldbereplacedwithanewBendix
unit,availableatanyauthorizedpartsoutlet.
EVERY MONTH, 10,000 MILES OR 350
OPERATING HOURS
1. Remove any accumulated contaminates and visually
inspecttheexteriorforexcessivecorrosionand physical
damage.
2. Inspect all air lines and wire harnesses connected to
the modulator for signs of wear or physical damage.
Replaceas necessary.
3. Testairline fittings forleakageand tighten orreplaceas
necessary.
4. Perform the ROUTINE OPERATION AND LEAKAGE
TESTINGdescribed in thismanual.
OPERATION & LEAKAGE TESTS
LEAKAGE TESTING
1. Park the vehicle on a level surface and block or chock
the wheels. Release the parking brakes and build the
air system to full pressure.
2. TurntheengineOFFandmake4or5brakeapplications
and note that the service brakes apply and release
promptly.
3. Build system pressure to governor cut-out and turn the
engineOFF.
4. After determining the pressure loss with the brakes
released (2 PSI/minute allowed), make and hold a full
servicebrakeapplication. Allowthepressuretostabilize
foroneminute.
5. Begintimingpressureloss for two minuteswhilewatch-
ingthe dash gauges for a pressure drop. The leakage
rateforthe servicereservoirsshould not exceed3PSI/
minute.
6. If either circuit exceeds the recommended two PSI/
minute, apply soap solution to the exhaust port of the
modular and any other components in the respective
circuit.
7. Theleakageatthe exhaust port ofmostBendixcompo-
nents,including M-30™modulators,should not exceed
a one-inch bubble in three seconds. If leakage at the
modulator is determined to exceed the maximum lim-
its, replace the modulator.
OPERATION TESTING
Toproperlytestthefunctionofthemodulatorwillrequire two
(2)service technicians.
1. Park the vehicle on a level surface and block or chock
the wheels. Release the parking brakes and build the
air system to governor cut out.
2. Turn the engine ignition key to the OFF position then
makeand holda fullbrake application.
3. With the brake application held and one (1) service
technicianposted atone (1) ofthe modulators,turn the
vehicle ignition key to the ON position. ONE OR TWO
SHORT bursts of air pressure should be noted at the
modulatorexhaust. Repeat the testforeach modulator
onthe vehicle. If atleasta single burstof exhaust isnot
noted or the exhaust of air is prolonged and not short,
sharpand welldefined, performthe ElectricalTests.
ELECTRICALTESTS
1. Before testing the solenoid assembly of a suspect
modulator,itslocationonthevehicleshouldbeconfirmed
usingtheTroubleshootingor Start Up procedureforthe
specificantilockcontrollerinuse. (SeetheService Data
Sheetfor theantilock controller forthis procedure.)
FIGURE 11 - M-30™MODULATOR CONNECTOR VIEWS
Electrical
Connector
43
Exhaust 41
Source
42
Hold
