TM 9-2320-209-10-3 BRAKE SYSTEM — Rearcoupling shut off valve — Tractor to trailer hose connections — Hydraulic brake fluid — Tire air pressure — Handbrake adjustment Air reservoir drain valve Trailer hookup air coupling shut off valve Figure 5-7. Troubleshooting Roadmap, Brake System WHEEL SYSTEM — Front tire pressures —Wheel stud nuts Figure 5-8. Troubleshooting Roadmap, Wheel System TA 113504 5-5