How do you adjust clutch brake on 1986 peterbilt?

To adjust the clutch brake on a 1986 Peterbilt, first, ensure the truck is on a level surface and the engine is off. Locate the clutch linkage and check the free play; it should typically be around 1 to 1.5 inches. Adjust the clutch brake by modifying the length of the pushrod or the adjusting screw on the clutch linkage until the free play is correct, ensuring smooth engagement without dragging. Finally, test the adjustment by pressing the clutch pedal to confirm proper operation.