7/31/2019 Brake Test Proceedure

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Special Instruction

Use of Brake Cooling Line Screens

to locate failed wheel brakes

7/31/2019 Brake Test Proceedure

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Job Purpose

• The purpose of the brake cooling line screens is to locate which wheel brake

has failed when debris is found in the hydraulic system screens

• This special instruction shows the locations of where the screens are to befitted in both 785C and 789C Off Highway Trucks

• The screens are to be installed into the brake cooling lines and the machinereturned to service for two hours

• The operator is to be made aware that brake testing is being carried out andinstructed to contact the workshop should any abnormality be experienced in

the trucks operation

• The screen with debris in it will indicate which wheel position has failed

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Test Proceedure

• The following test proceedure is to be used once brake lining debris has been found inthe hydraulic screens

• This proceedure is not intended to replace the use of the service manual• The service manual should be used as required to carryout further tests before the

machine is returned to service for testing

¾ Replace the hydraulic filters and clean the system screens

¾ Check and record the brake lining thickness for each wheel station

¾Check and record service brake and park brake pressures

¾ Install the brake cooling return line screens as illustrated in this special instruction,ensure the screens are clean prior to installing

¾ Perform a brake efficency test and record the results

¾ Return the machine to service for two hours

¾ An information tag should be fitted to the machine

¾ The operator and Minestar control are to be made aware that brake testing is beingcarried out on the truck and instructed to contact the workshop should any abnormalitybe experienced in the trucks operation

¾ A test proceedure form to record the required test results can be obtained from theworkshop leadhand

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785C Front Brake Screen Location

•Left side front, fit screen to bottom line •Right side front, fit screen to top line

•Insert cone end of screen into hose

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785C Rear Brake Screen Location

•Left side rear, fit screen to left line •Right side rear, fit screen to right line

•Insert cone end of screen into hose

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789C Front Brake Screen Location

•Left side front, fit screen to top line •Right side front, fit screen to bottom line

•Insert cone end of screen into hose

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789C Rear Brake Screen Location

•Left side rear, fit screen to left line•Right side rear, fit screen to right line

•Insert cone end of screen into hose

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¾ Once the machine has been in service for testing for two hours it should be

returned to the workshop and the brake cooling return line screens removed

and inspected

¾ The screen with debris in it will indicate which brake has failed

¾ The appropriate brake can now be removed and repaired

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Job Completion

• Once the repairs to the brake system have been completed the following work should be performed before the machine is returned to service, some of thiswork can be performed in advance while the brake is being repaired

¾ Hydraulic tank and screens should be thoroughly cleaned

¾ Hydraulic filters should be replaced

¾ Bleed the brake system of air

¾ Service brake and park brake pressures checked and recorded

¾ Brake lining thickness checked and recorded

¾ Brake efficency test performed and results recorded

¾ Once the machine has been returned to service the brake cooling linescreens should be thoroughly cleaned and returned to the tool store