ELECTRIC/HYDRAULIC BRAKE AND BRAKE DRUM (CONTINUED)
SYMPTOM
PROBLEM: REMEDY
NO BRAKES
Broken or Kinked Brake Line:
repair or replace.
Severe Underadjustment:
adjust brakes.
Malfunctioning Actuation System: See Section 5-4.
WEAK BRAKES
Brake Adjustment Not Correct:
manual adjust brakes automatic
make several reverse stops.
Excessively Worn Brake Linings:
replace shoe and lining.
Incorrect Lining:
install correct shoe and lining.
Grease or Fluid Soaked Lining:
repair grease seal or wheel cylin-
der, install new shoe and lining.
Frozen Master Cylinder or Wheel Cylinder Pistons:
recondition
or replace all cylinders, brake fluid.
Glazed Lining:
reburnish or replace.
Excessive Drum Wear:
replace.
Trapped Air in Lines:
bleed system.
Overloaded Trailer:
Correct.
Malfunctioning Actuating System: See Section 5-4.
HARSH BRAKES
Brakes Adjustment Not Correct:
manual adjust brakes,
See Sec-
tion 5-4.
Grease or Fluid on Linings:
replace shoes and linings.
SURGING BRAKES
Grease or Oil on Linings:
clean or replace.
Out of Round Drums or Cracked Drums:
machine or replace.
5-4
TROUBLESHOOTING BRAKE SYSTEM
5-4.1
Attach trailer to towing vehicle, but do not connect 7-way connector from truck to trailer.
5-4.2
Pull the break-a-way switch. The electrical/hydraulic unit should run. Do not run unit for more
than 2 minutes or it will get hot and damage unit. If the unit does not run, check battery condition and
system wiring. Reset the break-a-way switch which will turn the unit off.
Note: When the unit is running the motor will generate a “hum” that changes pitch as the unit
builds pressure.
5-4.3
Connect 7-way connector from truck to trailer. Turn the ignition switch on and check the in-cab
electronic brake controller to make sure green light is on. The electric/hydraulic unit should run when-
ever the brake pedal is depressed. The electric/hydraulic unit should pressurize when electronic man-
ual slide knob is slid over to apply brakes.
5-4.4
If the electric/hydraulic unit is not working correctly, then follow test for electric/hydraulic brake
actuators
(See Section 5-5).
CAUTION
TESTING THE ELECTRICAL/HYDRAULIC UNIT CONFIRMS THAT IT IS OPERATING.
IT DOES NOT CONFIRM THAT THE BRAKES ARE OPERATING PROPERLY. REGU-
LAR INSPECTION, ADJUSTMENT, AND MAINTENANCE OF THE BRAKES, LINES,
HOSES, DRUMS, DISCS, FLUID, AND OTHER ASSOCIATED COMPONENTS IS NEC-
ESSARY TO ENSURE PROPER BRAKE OPERATION.
5-4
Summary of Contents for 341
Page 2: ......
Page 3: ...MODEL 341 SEMITRAILER OPERATOR S MANUAL PURCHASED FROM DATE ADDRESS PHONE NO SERIAL NO i...
Page 8: ......
Page 12: ......
Page 24: ...3 12 Figure 3 7 Steps for Loading and Unloading...
Page 30: ...3 18 Figure 3 12 Rear Impact Guard System...
Page 38: ......
Page 44: ...4 6 Figure 4 2 341 Trailer Wiring Diagram...
Page 46: ...4 8 Figure 4 4 Truck Wiring Diagram...
Page 49: ...4 11 Figure 4 5 Examples of Camber Figure 4 6 Checking Axle for Bend...
Page 66: ...NOTES 5 10...