950G Wheel Loader, 962G Wheel Loader and IT62G Integrated Toolcarrier Braking System Caterpillar

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Personal injury or death can result if two persons are not used in the following procedure.

Use this procedure in order to inspect the wear on the discs for the service brakes. This procedure can also be used to estimate the remaining service life of the brake discs.

Each individual service brake uses an indicator pin to help determine the amount of wear on an existing service brake disc. An indicator pin is located on each side of the front and rear axle center housings.

Illustration 1	g00294502
End View of Axle Housing for the Service Brakes

Illustration 2	g00911102
View A-A

Illustration 3	g00294508
Detail B (1) Piston. (2) Friction disc. (3) Pin. (4) Plug. (5) Screw. (6) Cup. (7) Flange face for the axle housing.

Note: The following steps require accumulator pressure for the service brakes.

1. Start the engine. Run the engine until the brake accumulators reach the cutout pressure (less than 30 seconds).

2. Stop the engine. Engage the parking brake.

3. Thoroughly clean the area around plug (4) . Remove any excess paint that may be present on the flange face for the axle housing (7) . Plug (4) is held in place by screw (5) .

4. Remove screw (5) and plug (4) .

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Illustration 4	g00911104
(1) Piston. (2) Friction disc. (3) Pin. (6) Cup. (7) Flange face for the axle housing. (8) Depth micrometer. (9) Gauge block. (C) Dimension that is used to determine the amount of service life of a brake disc. (D) Thickness of gauge block (9) . (E) Total distance of the depth micrometer.

5. Apply light pressure to pin (3) in order to ensure that pin (3) is seated against cup (6) .

6. Measure dimension (C) with the service brakes in the APPLIED position. Dimension (C) equals the distance from the flange face for axle housing (7) to the end of pin (3) . Use a depth micrometer and the tools in Table 1 to measure dimension (C) .

   1. Use a caliper or a similar tool to determine the exact thickness (D) of gauge block (9) .

   2. Gauge block (9) is in the shape of the letter "U". Position gauge block (9) so that the slot straddles the hole in flange face (7) . Firmly hold gauge block (9) against flange face (7) .

   3. Measure dimension (E) .

   4. To determine the value of dimension (C) , subtract the value of dimension (D) from the value of dimension (E) .

      Note: If gauge block (9) is not available, use a depth micrometer with a half of a base to measure dimension (C) directly from flange face (7) . Shorten the base on the micrometer by grinding. This will help allow the base of the micrometer to rest on flange face (7) .

      Note: The baseline values for dimension (C) of the four service brakes was originally measured at the factory when the machine was new. The baseline values for dimension (C) are stored electronically on the machine's transmission electronic control module (ECM). Use the Caterpillar electronic technician (ET) in order to retrieve the baseline value of dimension (C) .

7. In order to retrieve the baseline values, perform the steps that follow.

   1. Stop the engine.
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   Illustration 5	g00940223
   Location of the Diagnostic Connector (10) Diagnostic connector (ET).

   2. Connect ET to diagnostic connector (10) .

   3. Turn the engine start switch key to the ON position, but do not start the engine.
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   Illustration 6	g00328764

   4. Start the ET software and select "Transmission 950" under the heading "Available ECMs".

   5. Select the "Configuration Tool" icon.
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   Illustration 7	g00328765

   Note: Record each value of dimension (C) on a piece of paper. The values that are shown on the screen are the baseline values for each of the four service brakes. The "Brk Meas Hourmeter" value is the reading on the service meter unit (SMU). The SMU reading was recorded when new brake discs were installed on the machine.

   Note: Do not modify the baseline value or the "Brk Meas Hourmeter" values that are stored in the transmission ECM. Change these values only when you install a new brake disc.

   6. Exit from the ET software.

   7. Turn the engine start switch key to the OFF position.

   8. Disconnect ET from diagnostic connector (10) .

8. Determine the amount of service life that is available for the left front service brake disc. Write down the value of dimension (C) for the left front service brake. This value was measured in Step 6. Write down the baseline value for the left front service brake that is stored in the transmission ECM.

9. Subtract the value of dimension (C) from the baseline value. In Illustration 7, the baseline value for the left front service brake equals 25.90 mm (1.020 inches). The difference indicates the amount of wear that has occurred to the service brake disc.

   Note: A difference of 1.46 mm (.058 inches) or more indicates that disc (2) must be replaced.

   Note: If you install a new brake disc in any of the four service brakes, you must enter a new baseline value. See the following reference.

   ReferenceFor more information about recording new baseline values, refer to Testing and Adjusting, "Service Brake Wear Indicator (New Brake Disc) - Check".

10. Repeat Steps 8 and 9 for the other service brakes.

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Illustration 8	g00110142
Oil Groove Depth of the Brake Discs

Note: The oil groove depth is the most critical dimension. If the depth of the oil grooves on the brake disc is too shallow, oil flow will be inadequate. This can cause excessive wear and abrasion.

11. To provide an estimate on the amount of service life for a brake disc, refer to Table 2.