TOOL BOX 1297249 - Caterpillar

Introduction
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 housings.Required Tools
Table 1
Required Tools
Part Number Description
185-5784 Brake Wear Gauge (1)
(1) This tool is not required for standard brake wear assessment. Use tool to measure discs (when removed from the axle) for a more precise estimate of remaining brake life.Test Preparation
Move machine to a smooth level surface.
Illustration 1 g03731188
Move steering frame lock to the LOCKED position.
Turn the engine start key to the OFF position.
Block the wheels.Test Procedure
Each service brake has a pin to determine the amount of wear on an existing service brake disc.
Illustration 2 g03581439
Illustration 3 g03739471
View A-A
Illustration 4 g03739472
Detail B
(1) Piston
(2) Friction disc
(3) Sleeve
(4) Indicator pin
(5) Shoulder
(6) Axle housingNote: This image shows brake wear indicator position with new brakes; the end of the pin does not protrude beyond the end of the sleeve. Brake discs need to be replaced when the pin shoulder (large diameter) protrudes.
Start the engine. Run the engine until the brake accumulator is charged.
Stop the engine. Engage the parking brake.
Clean the area around the brake wear indicator.
Apply the service brake.
Push the wear indicator pin (4) in until the pin contacts the brake piston (1).
Inspect the wear indicator pin (4). If the shoulder (5) protrudes past sleeve (3), the worn discs must be replaced.
Repeat step1 through step 3 for all service brakes.Note: If you install a new brake disc in any of the four service brakes, follow the adjustment procedure. Repeat Steps 5 through 8.
Prior to doing the next steps, sleeve (3) needs to be reset by pulling the sleeve out slightly.
Apply the service brake.
Push indicator pin (4) until contact is made with the brake piston.
Press sleeve (3) into the housing until the sleeve is flush with the end of wear indicator pin (4).
Illustration 5 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. Inadequate oil flow can cause excessive wear and abrasion.
To provide an estimate on the amount of service life for a brake disc, refer to Table 2. If the brake disc is removed from the housing, use the tool in Table 1 to measure the brake disc.
Table 2
Disc Thickness Wear Chart
Estimated Percentage of Remaining Brake Disc Life The Amount of Friction Material That has Worn From the Disc Oil Groove Depth(1)
100 0.00 mm (0.000 inch) 1.05 mm (0.041 inch)
80 0.29 mm (0.011 inch) 0.90 mm (0.035 inch)
60 0.58 mm (0.023 inch) 0.76 mm (0.030 inch)
40 0.88 mm (0.035 inch) 0.61 mm (0.024 inch)
20 1.17 mm (0.046 inch) 0.47 mm (0.018 inch)
0 1.46 mm (0.057