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Personal injury or death can result if two persons are not used in the following procedure. |
| NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, PERJ1017, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products. Dispose of all fluids according to local regulations and mandates. |
| Required Tools | |||
|---|---|---|---|
| Machine Sales Model | Part Number | Description | Qty |
| 924K Single Disc |
221-6893 | Brake Wear Gauge | 1 |
| 924K Single Disc |
221-6894 | Brake Wear Gauge | 1 |
| 930K/ Dual Disc Front Brakes and Rear Brakes | 221-6892 | Brake Wear Gauge | 1 |
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| Illustration 1 | g01410075 |
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Front axle (1) Inspection plugs | |
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| Illustration 2 | g01410077 |
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Rear axle (1) Inspection plugs | |
Each axle has two threaded inspection plugs (1) that are used for inspecting the corresponding brake disc. The inspection plugs are located on the front of the front axle and on the rear of the rear axle. The procedure to check the front brake discs for wear, is identical for the rear brake discs.
- Stop the engine. Engage the parking brake. Remove the inspection plug for the brake disc that is being checked.
Note: The following steps require accumulator pressure.
- Hold down either brake pedal. Holding down the pedal will hold the piston, the brake disc, and the plate together.
- Perform one of the following steps in order to check the brake disc for wear.
Note: A light and a mirror are needed in order to view the brake discs through the ports.
- Use a feeler gauge, or one of the brake wear gauges in Table 1 to measure the thickness of the brake disc. The minimum thickness of the friction disc should be within the specifications that are in Table 2.
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Table 2 Single Disc Brakes Model Serial Number Min Thickness of Disc Thickness of New Disc Min Groove Depth Brake Wear 924K Rear Brake PWR1-UP 6.35 mm (0.250 inch) 7.8 mm (0.307 inch) 0.32 mm (0.013 inch) Percent of Remaining Life Thickness of Friction Disc 100 7.8 mm (0.307 inch) 80 7.51 mm (0.296 inch) 60 7.22 mm (0.284 inch) 40 6.93 mm (0.273 inch) 20 6.64 mm (0.261 inch) 0 6.34 mm (0.250 inch) 924K Front Brake PWR1-UP 6.35 mm (0.250 inch) 7.8 mm (0.307 inch) 0.32 mm (0.013 inch) 100 7.8 mm (0.307 inch) 80 7.51 mm (0.296 inch) 60 7.22 mm (0.284 inch) 40 6.93 mm (0.273 inch) 20 6.64 mm (0.261 inch) 0 6.34 mm (0.250 inch) 930K Front Brake RHN1-UP 7.65 mm (0.300 inch) 9.10 mm (0.358) 0.32 mm (0.013 inch) 100 9.10 mm (0.358 inch) 80 8.81 mm (0.347 inch) 60 8.52 mm (0.335 inch) 40 8.23 mm (0.324 inch) 20 7.94 mm (0.3126 inch) 0 7.65 mm (0.301 inch) 930K Rear Brake RHN1-UP 7.65 mm (0.300 inch) 9.10 mm (0.358) 0.32 mm (0.013 inch) 100 9.10 mm (0.358 inch) 80 8.81 mm (0.347 inch) 60 8.52 mm (0.335 inch) 40 8.23 mm (0.324 inch) 20 7.94 mm (0.3126 inch) 0 7.65 mm (0.301 inch) Dual Disc Brakes Model Serial Number Min Thickness Thickness of New Disc Min Groove Depth Brake Wear 924K Rear Dual Disc Brake PWR1-UP 4.64 mm (0.183 inch) 5.8 mm (0.228 inch) 0.32 mm (0.013 inch) Percent of Remaining Life Thickness of Friction Disc 100 5.8 mm (0.228 inch) 80 5.57 mm (0.219 inch) 60 5.34 mm (0.210 inch) 40 5.1 mm (0.201 inch) 20 4.87 mm (0.192 inch) 0 4.64 mm (0.183 inch) 930K Rear Dual Disc Brakes RHN1-UP 8.07 mm (0.318 inch) 9.23 mm (0.363 inch) 0.32 mm (0.013 inch) 100 9.23 mm (0.363 inch) 80 9.00 mm (0.354 inch) 60 8.77 mm (0.345 inch) 40 8.54 mm (0.336 inch) 20 8.31 mm (0.327 inch) 0 8.08 mm (0.318 inch) - Select the appropriate gauge from Table 1. Insert the gauge between the reaction plates while the brakes are applied. The tool is a go/no-go gauge. If the tool fits between the reaction plates, the thickness of the brake disc is acceptable. If the tool does not fit between the reaction plates, the thickness of the brake disc is not acceptable and must be replaced.
Show/hide table
Illustration 3 g00110142 Note: The oil groove depth is the most critical dimension. If the depth of the oil grooves on the friction discs are too shallow, the oil flow will be inadequate. Inadequate oil flow can cause excessive heat and abrasion.
- Use a feeler gauge, or one of the brake wear gauges in Table 1 to measure the thickness of the brake disc. The minimum thickness of the friction disc should be within the specifications that are in Table 2.
- Measure the depth of the oil grooves on both sides of the friction discs in each axle housing. The depth of the oil grooves cannot be less than
0.32 mm (0.013 inch) .Note: If one or more of the brake discs do not comply with the minimum specifications, replace the worn disc before returning the machine to service.
- Install inspection plugs (1).
