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TC Series Hydraulic Brake ABS System

030.1-1

TC Series Hydraulic Brake ABS System

Blue Bird Corporation assumes sole responsibility

for ensuring that the information provided herein is

accurate to the best of its knowledge at the time of

printing. In keeping with its policy of continual

product improvement, Blue Bird reserves the right to

change product information without notice and

without incurring obligation. Some information

contained in this section has been re-published from

the following publications:

Eaton

Axle & Brake Service Manual, EB & ES

Models, Publication number BRSM-0033: April

1997. © Eaton Corporation, 1997. All rights

reserved.

Webb

Wheel Products, Inc. Installation, Service

and Safety Instructions Manual, Publication number

IM-298 (Supercedes IM-494).

Webb

Wheel Products, Inc. Torque Specifications,

Publication number SD-012: Revised April, 1997.

Multiple loose-leaf instruction pages provided by

Crewson Brunner

, Inc. on installing and

maintaining Automatic Slack Adjusters, no

publication number.

Holset

Air Compressor Field Service Manual, no

publication number or date.

MGM Brakes Model TR – Tamper Resistant Spring

Brakes, © MGM 12/92, Form Number 5026-MGM.

Midland™ EL1300 & EL1600 Air Compressor

Service Procedures, Publication Number L30002,

Rev. 9-93, © Midland-Grau Heavy Duty Systems.

Allied Signal Bendix

Brakes Air Brake Handbook,

Components, Maintenance and Troubleshooting, ©

AlliedSignal T.B.S. Co. 9/1996, Publication number

BW5057.

Allied Signal Bendix

Brakes TU-FLO 550

Compressor Service Data SD-01-333, ©

AlliedSignal 4/1996, Publication number BW1639.

Allied Signal Bendix

Brakes WS-20 Antilock

Wheel Speed Sensor Service Data SD-13-4754, ©

AlliedSignal T.B.S. Co. 11/1996, Publication

number BW1662.

Allied Signal Bendix

Brakes M-21 and M-22 Antilock Modulator

T.B.S. Co. 11/1996, Publication number BW1664.

Allied Signal Bendix

Brakes EC-17 Antilock

AlliedSignal T.B.S. Co. 2/1998, Publication number

BW1910.

Allied Signal Bendix

Brakes AD-9 Air Dryer

Co. 5/1996, Publication number BW1627.

Allied Signal Bendix

Brakes Push-Pull Type

AlliedSignal T.B.S. Co. 4/1996, Publication number

BW1578.

Allied Signal Bendix

Brakes E-6 & E-10 Dual

AlliedSignal 6/1996, Publication number BW1427.

Allied Signal Bendix

Brakes R-12 & R-14 Relay

6/1996, Publication number BW1431.

Summary of content (20 pages)

PAGE 1
Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System TC Series Hydraulic Brake ABS System Blue Bird Corporation assumes sole responsibility for ensuring that the information provided herein is accurate to the best of its knowledge at the time of printing. In keeping with its policy of continual product improvement, Blue Bird reserves the right to change product information without notice and without incurring obligation.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Table of Contents Table of Contents .......................................... 2 Safety.............................................................. 3 Warnings and Cautions................................ 3 Introduction................................................... 3 Description of Operation.............................. 3 Electronic Control Unit (ECU) Identification .................................................
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Safety Introduction The purpose of this safety summary is to ensure the safety and health of personnel and the protection of equipment. This supplement contains information for the Meritor Version D hydraulic ABS. All users of this publication shall read, understand, and apply this safety summary when performing maintenance and operating procedures.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Electronic Control Unit (ECU) Identification Note Do not open the ECU. Opening the ECU to gain access to the internal components will void the warranty. To determine the hydraulic ABS version installed on the vehicle by looking at the ECU. D version has three (3) connectors, see Figure 1—Version C and D ECU. Figure 1—Version C and D ECU Figure 1.2—A Typical Meritor WABCO Hydraulic ABS System 030.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System System Components The following components are the Meritor WABCO Hydraulic ABS: • Electronic Control Unit, see Figure 1.3— Electronic Control Unit 4. Sensors contain brake fluid and must be handled with appropriate care. 1. Processes sensor signals and generates solenoid valve commands to reduce maintain or reapply brake pressure. 2.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System • Sensor Spring Clip, see Figure 1.6—Sensor Spring Clip. • Holds the wheel speed sensor in close proximity to the tooth wheel. 7. Two-wire cable with molded-on connector. Figure 1.6—Sensor Spring Clip Figure 1.8—Sensor Extension Cables • • Tooth Wheel, see Figure 1.7—Tooth Wheel A machined or stamped ring mounted to a machine surface on the hub of each ABSmonitored wheel. • Sensor Extension Cables, see Figure 1.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Component Removal and Installation Sensors • Sensor Lubrication Specification Meritor WABCO specifications require a sensor lubricant to have the following properties. 1. Lube must be mineral oil-based and contain molydisulfide. 2. Lube should have excellent anti-corrosion and adhesion properties, and be capable of continuous function in a temperature range of 3. –40° to +300° Fahrenheit.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System 8. Replace tire and drum if required. Remove safety stands, lower the vehicle, and remove the chocks from front tires. 9. Perform a voltage output check to ensure proper installation, refer to Sensor Output Voltage Test in troubleshooting section. Modulator Assembly Modulator Assembly Removal BRAKE FLUID IS FLAMMABLE AND TOXIC TO SKIN, EYES AND RESPIRATORY TRACT. SKIN AND EYE PROTECTION IS REQUIRED.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System 2. Master Cylinder Filling and Bleeding DO NOT USE OR MIX DIFFERENT TYPES OF HYDRAULIC FLUID. THE WRONG HYDRAULIC FLUID WILL DAMAGE THE RUBBER PARTS OF THE BRAKE CALIPER AND CAN CAUSE DAMAGE, LOSS OF BRAKING AND SERIOUS INJURY. • Replenish reservoir with the specified brake fluid. • Depress braking pedal 5 times in 5 seconds using only the stroke between 1/3 of maximum value.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Manual Bleeding BRAKE FLUID IS FLAMMABLE AND TOXIC TO SKIN, EYES AND RESPIRATORY TRACT. SKIN AND EYE PROTECTION IS REQUIRED. AVOID REPEATED OR PROLONGED CONTACT. DRAIN FLUID IN A WELL-VENTILATED AREA. Do not let the brake master cylinder fluid level get too low during the bleeding operation. Do not release the brake pedal until the fitting has been tightened. Failure to do so will allow air bake into the system. 5.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Figure 3—Pin Numbers and Locations 030.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System 9-Pin ECU Connector 18-Pin ECU Connector 15-Pin ECU Connector Pin Circuit Pin Circuit Pin Circuit Number Description Number Description Number Description 1 2 3 4 5 6 7 8 9 ------------------- Left Front Sensor Left Front Sensor Right Rear Sensor Right Front Sensor Right Front Sensor Right Rear Sensor Left Rear Sensor Left Rear Sensor Not Used ------------------- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Schematic 1—4S/4M D Version Hydraulic ABS Wiring Diagram 030.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Blink Code Diagnostics • ABS Indicator Lamp This lamp, located on the vehicle dash, serves two purposes: 1. Alerts drivers or service personnel to a possible fault in the hydraulic ABS, as follows: • If the ABS indicator lamp comes on briefly then goes to off when the ignition is turned on, there are no active or stored faults in the hydraulic ABS.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Note If you receive a blink code that is not identified in Table 2, contact the Meritor Customer Support center at (800) 535-5560. Step 1 Turn ignition key on Do not turn engine on. Press Blink Code Switch once, then release. Step 2 Response Status Action ABS indicator lamp Does not come on Loose or burned Out bulb Repair or replace lamp bulb. Voltage not within acceptable range (9.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Using Blink Code Diagnostics (continued) Use the information in Table 3 to identify a fault, check for proper volt or ohm measurements, and repair the fault. 1. Identify and record the blink code. Blink codes are identified in columns 1 and 2. 2. Test the pins indicated. Pin locations to be tested are listed in column 3. 3. Compare the measurement received against the correct volt or ohm measurement listed in column 4.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Ignition Key On to determine Ignition Key off to test system (except where noted) ABS blink code fault 1 2 3 4 5 Fault Code Problem Area Connector Pins to be Tested Correct Volt Ohm Meter Reading Action 3-1 Right Front sensor—Air gap 9-pin 4 and 5 Greater than 0.2 volts AC at 30 rpm (Rotate wheel ½ revolution per second) Check for sensor adjustment. Check for excessive wheel bearing endplay.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Ignition Key On to determine Ignition Key off to test system (except where noted) ABS blink code fault 1 2 3 4 5 Fault Code Problem Area Connector Pins to be Tested Correct Volt Ohm Meter Reading Action 7-7 Recalculation pump does not switch off. OR Recirculation pump does not switch on (low level with act.) Recirculating pump motor locked.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Sensor Adjustment When troubleshooting or testing the ABS system, do not damage the connector terminals. Do not pry or push sensors with sharp objects. Voltage Check Note Sensor will self-adjust during wheel rotation. No gap is allowed at installation. During normal operation, a gap not exceeding 0.04 inch is allowable. Voltage must be between 9.5 and 14 volts for the 12 volt hydraulic ABS to function properly.
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Directory Previous Previous Next Search Exit TC Series Hydraulic Brake ABS System Sensor Resistance • The sensor circuit resistance must be between 500 and 2000 ohms. Measure resistance at the sensor connector, or at the pins on the ECU connector. • 8. Measure output at the pins, see Table 4—Sensor Check Pins. 7. Turn ignition off. • To measure resistance at the sensor connector, disconnect the sensor from the sensor extension cable.