TM  10-3930-638-24&P 2-41.   BRAKE   SYSTEM   TROUBLESHOOTING   (cont.) MALFUNCTION TEST  OR  INSPECTION CORRECTIVE ACTION 6.  SERVICE  BRAKES  OVERHEAT  (cont) Step  2. 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 in released position. WARNING Before raising axle off ground, be sure that shipping lock pin is installed. Failure to do so may cause vehicle to turn and slip off jack 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 off ground. Rotate wheel by hand: there should be a very slight dragon wheel. Repeat  above  for  remaining  wheel  and  axle. a. If there is a very slight drag on wheels, proceed to step 3. b. If there is excessive dragon wheels, adjust brakes (para 2-43a). Step 3. Remove axle shafts and hub and drum assemblies from one axle (para 2-39f). Check brake shoe return spring (para 2-43a). Repeat  above  for  remaining  axle. a.  If  brake  shoe  return  spring  is  permanently  set,  replace  (para  2-43a). b. If brake shoe return spring is okay, proceed to step 4. Step 4. Check wheel cylinders for leaking condition or sticking piston (para 2-43a, step 1). If wheel cylinder is leaking or piston is sticking, replace wheel cylinder (para 2-43a). 7. EXCESSIVE SERVICE BRAKE PEDAL TRAVEL NOTE If there is excessive brake pedal travel, add brake fluid to master cylinder (para 2-43c(1)) and bleed air from brake system as de- scribed in paragraph 2-43a. If brake pedal travel is still excessive proceed to step 1 below. Step 1. Check adjustment of service brake pedal free travel (para 2-43e). a. If service brake pedal is not adjusted properly, adjust (para 2-43e). b. If adjustment is okay, proceed to step 2. 2-265