PLATE 3863920 - Caterpillar

Remove Air From The Wheel Brake Hydraulic Circuit (Bleed The Brakes)
Make reference to on first page of AIR SYSTEM AND BRAKES TESTING AND ADJUSTING section.
Air must not be in the hydraulic circuit. Air in the system can prevent complete brake application and it is possible that the wheels on the machine can not be stopped. Keep both brake fluid reservoirs full of brake fluid during the air removal procedure.1. Start the engine and let the air pressure go up to normal pressure for operation. Keep the engine in operation during this procedure to make sure of correct air pressure.2. Push and hold the right brake pedal down.3. Loosen (open) bleeder screws (1) on the master cylinders.4. Tighten (close) bleeder screws (1) and release the right brake pedal.
BLEEDER SCREWS FOR THE MASTER CYLINDERS
1. Bleeder screws for the master cylinders.5. Do Steps 2 thru 4 again until there is a constant flow of brake fluid (all of the air is removed) from each bleeder screw on the master cylinders.
BLEEDER SCREWS FOR THE WHEEL BRAKE
2. Bleeder screws.6. Push and hold the right brake pedal down. Bleed only one wheel at a time.7. Open bleeder screws (2) at a wheel brake.8. Close bleeder screws (2) and release the right brake pedal.9. Do Steps 6 thru 8 again until there is a constant flow of brake fluid from bleeder screw (2).10. Do Steps 6 thru 9 again at each wheel brake until all of the air is removed from the system.Hot Or Dragging Brakes
0 to 1380 kPa (0 to 200 psi) Gauge.6.4 mm (.25 in.) diameter by 127 mm (5 in.) long bolt.
Make reference to on first page of AIR SYSTEM AND BRAKES TESTING AND ADJUSTING section.
Use the procedure that follows to correct a problem of hot or dragging brakes:
LOCATION TO INSTALL GAUGE
1. Drain valve for the air reservoir.
AIR/HYDRAULIC CYLINDERS
2. Brake fluid pressure switch for rear wheel brakes. 3. Brake fluid pressure switch for front wheel brakes (under bracket). If the brake fluid pressure indicator is on, go to Step 9b.1. Install a 0 to 1380 kPa (0 to 200 psi) gauge in drain valve (1) of the air reservoir.2. Remove brake fluid pressure switch (2) and the indicator rod from the air/hydraulic cylinder. Use a 6.4 mm (.25 in.) diameter bolt that is 127 mm (5 in.) long, in place of the indicator rod. Two bolts can be used to check both master cylinders at the same time.3. Start the engine and let the air pressure go up to cutout pressure [620 to 690 kPa (90 to 100 psi)]. Stop the engine. Make sure air pressure is above 620 kPa (90 psi) when the master cylinder stroke is checked.
INDICATOR ROD REMOVED AND
6.4 mm (.25 in.) BOLT INSTALLED (TYPICAL ILLUSTRATION) 4.127 mm (5 in.) bolt.4. With the brake fully released, push bolt (4) down until it comes in contact with the piston in the air chamber.5. Measure the length of the rod.6. Push and hold the right brake pedal down.7. Push bolt (4)