ROD A 9J7777 - Caterpillar

Illustration 1 g06221939
Service brake
(A) Thickness of a brake disc
(1) Piston
(2) Brake disc
(3) Reaction plateThe minimum thickness of a worn brake disc is 4.88 mm (0.192 inch). The thickness of a new brake disc is 6.10 0.13 mm (0.240 0.005 inch). Service the brakes before the thickness of the brake disc is less than 4.88 mm (0.192 inch).
Illustration 2 g00110142
Measuring the oil groove depth
Oil groove depth is the most critical dimension. If the oil grooves on the brake discs are too shallow or gone, oil flow will be inadequate. This occurrence will cause excessive wear and abrasion. See Table 1.Use a depth gauge to measure the depth of the oil grooves on both sides of each brake disc in each axle housing. The depth of the oil grooves must be greater than 0.38 mm (0.015 inch).
Table 1
Brake Disc Wear Information
Percentage of Remaining Brake Disc Life Disc Thickness Oil Groove Depth
100 6.10 mm (0.240 inch) 1.05 mm (0.041 inch)
80 5.86 mm (0.231 inch) 0.92 mm (0.036 inch)
60 5.61 mm (0.221 inch) 0.78 mm (0.031 inch)
40 5.37 mm (0.211 inch) 0.65 mm (0.026 inch)
20 5.12 mm (0.202 inch) 0.51 mm (0.020 inch)
0 4.88 mm (0.192 inch) 0.38 mm (0.015 inch)