TM 9-2330-235-14&P
4-25.
BLEEDING HYDRAULIC BRAKE SYSTEM.
This Task Covers:
a. Manual Bleeding
b. Pressure Bleeding
Initial Setup:
Equipment Conditions:
Materials/Parts:
Brake fluid (Item 6, Appendix E)
Trailer coupled to towing vehicle (manual bleeding
Rags (item 12, Appendix E)
only) (ara 2-8).
Tools/Test Equipment:
General mechanic's tool kit
Personnel Required: Two
Common no.1 shop set
Drain pan
Pressure bleeder
a.
MANUAL BLEEDING
NOTE
A suitable container should be used to catch any draining brake fluid. Ensure that all spills are
cleaned up.
1. Clean wheel cylinder bleeder valves at top and bottom of brake backing plate.
2. Attach bleeder tube to lower bleeder valve.
3. Submerge free end of bleeder tube in approximately 3 in. (7.6 cm) of clean brake fluid. Use a clean, clear jar or
bottle to hold brake fluid.
NOTE
Master cylinder must be kept full during bleeding operation to prevent air from entering the
system.
4. Remove filler plug from top of master cylinder and fill with brake fluid to within X in. (13 mm) from top.
5. Have assistant depress brake pedal of towing vehicle and hold until instructed to release.
6. While assistant depresses brake pedal, open bleeder valve 4 turn counterclockwise.
7. Close bleeder valve by turning clockwise.
8. Instruct assistant to release brake pedal, then pump brake pedal to maximum height, then depress and hold brake
pedal until instructed to release it.
9. Repeat steps 5 through 8 until all air is purged from the line (approximately four times after last bubbles are
discharged from bleeder tube).
10. Remove bleeder tube from lower bleeder valve and attach to upper bleeder valve of same wheel.
11. Fill master cylinder with brake fluid to within X in. (13 mm) from top.
12. Repeat steps 5 through 8 for upper bleeder valve.
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