TM    10-3930-638-24&P 2-41. BRAKE SYSTEM TROUBLESHOOTING (cont) MALFUNCTION TEST  OR  INSPECTION CORRECTIVE ACTION 8. EXCESSIVE SERVICE BRAKE PEDAL EFFORT REQUIRED (cont) Step 7. (cont) Operate engine at 1700 to 1900 RPM. With lift control lever held towards you, note and record pres- sure gage reading; then pump service brake pedal several times. Depress service brake pedal and record new pressure gage reading. Compare  difference  between  pressure  gage  readings  (relief  pressure). If difference between pressure gage readings is not 245 to 255 PSI replace or repair power assist unit (para 2-43c(2)). 9. SERVICE BRAKES GROAN AT END OF STOP Step 1.   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 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  from  ground. Remove  both  axle  shafts  and  hub  and  drum  assemblies  (para  2-39f). Check  brake  linings  for  wear,  uneven  wear,  brake  fluid/lubricant  contamination,  or  excessive  dust (para  2-43a). Repeat for other axle. a. Replace brake linings if worn or contaminated: remove excessive dust (para 2-43a). b. If brake linings are okay, proceed to step 2. Step 2. 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 3. Step 3. Check for loose, missing, or damaged brake shoe mounting hardware (para 2-43a). Replace missing or damaged brake shoe mounting hardware; install new hardware if missing. 10. SCRAPING NOISE FROM SERVICE BRAKES WHEN APPLIED Step 1.   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. 2-269