TM 10-3930-638-24&P 2-41.   BRAKE   SYSTEM   TROUBLESHOOTING   (cont) MALFUNCTION TEST  OR  INSPECTION CORRECTIVE ACTION 2. UNEVEN OR ERRATIC SERVICE BRAKES Step 1. Check if air pressure is the same in each tire (should be 45 PSI). a. If air pressure in each tire is not 45 PSI, adjust tire pressure. b. If air pressure is okay, proceed to step 2. Step 2. Check hydraulic brake valve for leaking condition (para 2-43c). a. If hydraulic brake valve is leaking, replace it (para 2-43c). b. If hydraulic brake valve is okay, proceed to step 3. Step 3. Place blocks (6 by 6 by 18 inches wood blocks) at each wheel to prevent vehicle from moving. Remove  shipping  lock  pin  from  storage  area  under  operator’s  seat  (para  2-4b(1))  and  install  in  chassis. Ensure that parking brake is applied. WARNING Before raising wheel off ground, be sure that shipping lock pin is installed. Failure to do so may cause vehicle to turn and slip off jacks or jack stands causing serious injury or death. If you are in- jured by falling equipment, obtain medical aid immediately. Raise  one  axle  and  wheels  from  ground. Remove both wheel axle shafts and hub and drum assemblies (para 2-39f). Check wheel cylinders for leaking condition or sticking piston (para 243a, step 1) Repeat  for  other  axle  and  wheels. a. If wheel cylinder is leaking or piston is sticking, replace wheel cylinder (para 2-43a). b. If wheel cylinder is okay, proceed to step 4. Step 4. Check brake linings for wear, uneven wear, glaze, brake fluid or lubricant contamination, or excessive dust. a. Replace brake linings if worn, glazed, or contaminated; remove excessive dust (para 243a). b. If brake linings are okay, proceed to step 5. Step 5. Check hub and drum assemblies for scored or cracked condition (para 2-39f). a. Replace brake drums if scored or cracked (para 2-39f). b. If hub and drum assemblies are okay, proceed to step 6. Step 6. Check for loose, missing, or damaged brake shoe mounting hardware (para 243a). Replace missing or damaged brake shoe mounting hardware; install new hardware if missing. 2-261