2011/05/31 Correction to Operation and Maintenance Manual , "Braking System - Test" {4250, 4251, 4267} Caterpillar

Underground Articulated Truck:

AD55B (S/N: JNW1-UP)

Operation and Maintenance Manual, SEBU7336, "AD55B Underground Articulated Truck", "Braking System - Test". This manual is part of Service Manual, KENR6715 Volume 2.

The engine speed for checking the parking brake holding ability is now 1600 rpm. Replace the information with the following information.

Braking System - Test

Be sure that the area around the machine is clear of personnel and obstructions. Be sure that the steering frame lock is in the stored position.

Test the brakes on a dry, level surface. Fasten the seat belt before testing the brakes.

The following tests are to determine if the parking brake and the service brakes are functional. These tests are not intended to measure the maximum brake holding effort. Brake holding effort required to hold a machine at a specific engine rpm will vary from machine to machine. These differences are due to engine settings, power train efficiency, as well as differences in brake holding ability.

Engine rpm at beginning of machine movement, with the brake applied, should be compared against the engine rpm on a prior test. This test will indicate system deterioration.

To carry out the brake test, first start the engine and let the brake oil pressure build up to the operating range. The parking brake will stay engaged until operating oil pressure has been reached and the parking brake control is moved to the OFF position. As soon as operating oil pressure has been reached a test of the braking system can be commenced.

Service Brake Holding Ability Test

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Personal injury can result if the machine moves while testing. If the machine begins to move during test, reduce the engine speed immediately and engage the parking brake.

1. Move the transmission control to the NEUTRAL position. Start the engine.

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Illustration 1	g01007744

2. Depress service brake pedal (1) .

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Illustration 2	g01417751

3. Disengage the parking brake by moving parking brake control (2) to the OFF position.

4. Move transmission control (3) to the FIRST SPEED FORWARD position.

5. Gradually increase the engine speed to 1750 rpm. The machine should not move.

6. Reduce the engine speed to low idle. Move the transmission control to the NEUTRAL position. Engage the parking brake. Stop the engine.

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NOTICE
If the machine moved while testing the brakes, contact your AVSpare dealer. Have the dealer inspect and, if necessary, repair the service brake before returning the machine to operation.

Parking Brake Holding Ability Test

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NOTICE
The standard parking brake control is a pull-to-engage type. When the knob is pulled OUT, the parking brake will be engaged. Certain mining regulations require machines to be equipped with a push-to-engage parking brake control. When the knob is pushed IN, the parking brake is engaged. Before operating the machine, ensure you are familiar with the operation of the parking brake control.

Standard Pull-to-Engage Type

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Personal injury can result if the machine moves while testing the parking brake. If the machine begins to move during the test, reduce the engine speed immediately and apply the service brakes.

1. Move the transmission control to the NEUTRAL position. Start the engine.

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Illustration 3	g01417752

2. Engage the parking brake by pulling parking brake control (1) out to the ON position.

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Illustration 4	g01417755

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Illustration 5	g01417757

3. Move transmission control (2) to the FIRST SPEED FORWARD position.

   Note: Parking brake indicator (4) and action lamp (3) should illuminate. The action alarm should sound.

4. Gradually increase the engine speed to 1600 rpm. The machine should not move.

5. Reduce the engine speed to low idle. Move the transmission control to the NEUTRAL position. Stop the engine.

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NOTICE
If the machine moved while testing the brakes, contact your AVSpare dealer. Have the dealer inspect and, if necessary, repair the parking brakes before returning the machine to operation.

Optional Push-to-Engage Type

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Personal injury can result if the machine moves while testing the parking brake. If the machine begins to move during the test, reduce the engine speed immediately and apply the service brakes.

1. Move the transmission control to the NEUTRAL position. Start the engine.

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Illustration 6	g01417763

2. Engage the parking brake by pushing parking brake control (1) in to the ON position.

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Illustration 7	g01335741

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Illustration 8	g01417757

3. Move transmission control (2) to the FIRST SPEED FORWARD position.

   Note: Parking brake indicator (4) and action lamp (3) should illuminate. The action alarm should sound.

4. Gradually increase the engine speed to 1600 rpm. The machine should not move.

5. Reduce the engine speed to low idle. Move the transmission control to the NEUTRAL position. Stop the engine.

Show/hide table

NOTICE
If the machine moved while testing the brakes, contact your AVSpare dealer. Have the dealer inspect and, if necessary, repair the parking brakes before returning the machine to operation.