TM10-3930-660-20 Table 2-3. Mechanical Troubleshooting (Cont’d) MALFUCTION TEST OR INSPECTION CORRECTIVE  ACTION — . 39. BRAKES WILL NOT RELEASE Step 1. Check that brake pedal is returning to full up position. Inspect brake linkage and spring. Replace linkage and spring if necessary, para. 12-7. Step 2. Inspect  pistons  in  service  brake  caliper  for  binding. Replace service brake calipers if necessary. Refer to Direct Support Maintenance. Step 3. Check for restrictions and excessive back pressure in return line. Remove restriction in return line. Replace or repair lines as necessary, para. 12-9. 40. ENGINE CANNOT MOVE VEHICLE OR HAS DIFFICULTY MOVING VEHICLE Step 1. Check parking brake for dragging condition. Inspect and adjust parking brake, para. 12-4. Step 2. Check service brakes for dragging condition. Inspect and, if necessary,   replace service brake caliper(s). Refer to Direct Support Maintenance. Step 3. Check for a broken propeller shaft. Replace propeller shaft and/or U-joints, para. 10-3. 41. BRAKES CHATTER OR ARE NOISY Step 1. Check for air in brake system. Bleed brake system to purge air from system, para. 12-5. Step 2. Check for loose or worn service brake shoes. Replace service brake shoes if required, para. 12-6. 2-45