TP-0672 - Meritor WABCO
Contents
1. Do not release the brake pedal E With the brake pedal still applied use a torque wrench to close the bleeder fitting screw 5 Use a torque wrench to tighten the bleeder fitting screw to 35 39 in lb 4 4 5 Nem 4 6 Repeat Step 4 and Step 5 for the other axle 7 Use hose clamp pliers to clamp the rubber hose at least three inches 76 mm away from the entrance to the HCU reservoir Use care to avoid damage to the plastic reservoir nipple inside the hose Figure 1 4006218a Figure 3 12 Use denatured alcohol and lint free rags to clean the valve mounting surface Ensure there is no rubber sticking to the HCU Do not allow rubber or other debris to fall into the HPB bore holes Figure 4 4006216a Figure 1 NOTE Avoid bending or kinking the brake lines while disconnecting and handling other components 8 Disconnect the two master cylinder brake lines from the relay 4006219a valve Plug the two lines to prevent contamination Figure 4 TP 0672 Issued 08 06 16579 22882 Page 2 Copyright ArvinMeritor Inc 2006 Printed in USA Installation 1 Place a screw into the center mounting hole of the relay valve Use a hex head socket tool for positioning Place the new relay valve seal onto the relay valve using the screw to align the seal The orientation should match Figure 5 Position the relay valve against the HCU Thread the screw into the HCU oc SEAL PLATE ol IDENTIFICATION Tightening sequence Tigh2. MERITOR WABCO Technical Bulletin Hazard Alert Messages Read and observe all Warning and Caution hazard alert messages in this publication They provide information that can help prevent serious personal injury damage to components or both How to Obtain Additional Maintenance and Service Information Refer to Maintenance Manual MM 0401 Meritor WABCO Hydraulic Power Brake HPB System To obtain this publication call ArvinMeritor s Customer Service Center at 800 535 5560 Meritor WABCO publications are also available on our website www meritorwabco com For OnTrac dealer support call 1 866 ONTRAC 1 668 7221 HCU Relay Valve Replacement Procedures This publication provides instructions for the removal and installation of HCU relay valves Please read these instructions completely before attempting to service the system and carefully follow all outlined procedures Required Equipment e Denatured alcohol e Lint free tissues or rags e Torque wrench capable of 35 71 in lb 4 8 Nem e 4mm hex head socket Drive ratchet e Hose clamp pliers for 34 inch 19 5 mm rubber hose TP 0672 Issued 08 06 Hydraulic Compact Unit HCU Relay Valve Replacement Procedure Before Performing Service Procedures Before working on the HPB braking system you must depressurize the system Failure to depressurize the system may result in serious personal injury Depressurization instructions are outlined under Step 4 of Remov
3. al on page 2 of this bulletin 4 amp WARNING To prevent serious eye injury always wear safe eye protection when you perform vehicle maintenance or service Park the vehicle on a level surface Block the wheels to prevent the vehicle from moving Support the vehicle with safety stands Do not work under a vehicle supported only by jacks Jacks can slip and fall over Serious personal injury and damage to components can result Release all air from the air systems before you remove any components Failure to depressurize the system may result in serious personal injury The full power brake system is a pressurized system that achieves pressures up to 2320 psi 160 bar This pressure is not reduced by switching the ignition off or removing battery power Prior to servicing this system the depressurization procedures must be performed exactly as presented Failure to depressurize the system may result in personal injury or death 4 amp CAUTION The HPB system is a complex device that provides optimum efficiency and operation If the system sustains damage or a component malfunctions and requires replacement the replacement procedures provided by Meritor WABCO must be followed exactly with the associated steps performed in the order presented Hydraulic brake fluid is a caustic substance Contact with the hydraulic brake fluid can cause skin irritation Do not let hydraulic brake fluid touch any painted surfaces as it will remove
4. rain Reservoir ECU Information ECU Type Part Number Manufacture Date Serial Number Software Rev Figure 7 Copyright ArvinMeritor Inc 2006 Heuay iooos5s0 HEAAOOI8 J Wheel Sensor Left Front Right Front Left 2nd Right 2nd 0 0 0 0 4006222a TP 0672 Issued 08 06 Page 3 py Drain Accumulators Depleting Rear Accumulator 557 Depleting Front Accumulator 4006223a Figure 8 12 Verify fluid is at the maximum level 13 Use TOOLBOX Software to verify correct system function Check for e System Pressure Main Screen e System Faults Fault Information Screen 14 Record then repair any new fault occurrences Clear the system faults MERITOR WABCO Meritor WABCO Vehicle Control Systems Information contained in this publication was in effect at the time the publication was approved for printing and is subject to 2135 West Maple Road change without notice or liability Meritor WABCO reserves the right to revise the information presented or to discontinue the Troy MI 48084 7121 USA production of parts described at any time 800 535 5560 meritorwabco com Copyright 2006 TP 0672 ArvinMeritor Inc Issued 08 06 All Rights Reserved Printed in USA 16579 22882
5. ten each bolt twice 4006221a Figure 5 2 Place the remaining four screws into the mounting holes on the relay valve Hand tighten all five screws 3 Use a torque wrench to tighten all five screws to 71 in lb 8 Nem following the numbered sequence illustrated in Figure 5 4 4 Attach the master cylinder brake lines Remove the hose clamp from the low pressure hose 5 Refill the master cylinder reservoir The HCU reservoir will require some filling and some fluid will gravity feed down the low pressure hose 6 Verify the master cylinder is filled to the MAX fill line or above 7 Install a bleeder adapter cap and apply pressure to the master cylinder reservoir Use filtered and regulated air and regulate the air to 35 psi 2 4 bar The fluid level may drop significantly after applying pressure as the HCU reservoir fills If this occurs pressure must be removed and fluid must be added to the maximum level again 8 Bleed the relay valve circuit If all of the fluid was drained from the HCU reservoir during the replacement procedure air was able to enter the system If this is the case bleed the axle circuits Refer to Meritor WABCO maintenance manual MM 0401 for bleed instructions 16579 22882 Printed in USA NOTE The following steps require TOOLBOX Software Refer to the TOOLBOX user s manual TP 99102 for complete operating instructions A copy of this manual is available on the web meritor
6. the paint Hydraulic brake fluid may also damage certain non metal surfaces Do not let fluid contact brake pads shoes rotors or discs Before disposing of used components verify the warranty status Contact OnTrac at 866 668 7221 for instructions Removal 9 Use a 4 mm socket wrench to loosen and remove the five Allen head screws that secure the relay valve to the hydraulic compact unit HCU Figure 2 1 Wear safe eye protection 2 Park the vehicle on a level surface Block the wheels to prevent the vehicle from moving 3 Disconnect the battery 4 Apply the brake pedal a minimum of 30 times to decrease pressure in the system To ensure the system is depressurized perform the following check on both the front and rear axles A Remove the protective cover from the end of the bleeder fitting on one brake caliper B Attach a bleeder bottle hose to the bleeder fitting at the wheel end Submerge the free end of the bleeder hose 400621 7a into the bleeder bottle Both the tubing and container Figure 2 must be able to withstand the chemical effects of hydraulic brake fluid 10 Carefully lower and remove the relay valve C Use a wrench to open the bleeder fitting screw 11 Remove and discard the rubber coated seal plate Do not reuse this plate During installation use the new seal plate D Apply and hold the brake pedal down until no more brake included with the relay valve replacement kit Figure 3 fluid runs out
7. wabco com With pressure on the system reconnect the batteries After reconnecting the batteries turn the ignition on Connect TOOLBOX Software to the vehicle Use this software to verify pressure is building correctly Figure 6 yy Meritor WABCO HPB Tractor ECU Display Co ECU Information ECU Type Part Number Manufacture Date Serial Number Software Rev gt Faults free Existing r Control Status ABS Brake ABS Retarder ATC Brake ATC Engine PB Travel Switch Figure 6 None Released qo Na oo C HPB OAA eaeoas0012 mponent Tests Parameters EOL Help Wheel Sensor Left Front Right Front Left 2nd Right 2nd Learned Component Stored Retarder Relay Switches ATC Foot Brake Parking Brake Brake Fluid Off Off Centered Pressure psi Front Axle 1222 ATC Enabled ao Ga S Road Speed o mph Voltages Battery 11 40 ma Ignition m Lamps ABS ATC Brake forf forf forf 1438 Rear Asle 10 24AM 4006207a 4 10 2006 10 Remove pressure from the master cylinder reservoir and remove the adapter cap 11 After the accumulators have fully charged approximately 2100 psi 145 bar deplete the system pressure Under the EOL menu on the HPB screen select Deplete Accumulators Figure 7 and Figure 8 Meritor WABCO HPB Tractor ECU Display Component Tests Parameters EOL Help b Q lima Sel D
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