3-65. What is the first step in replacing  an  O-ring  in  a disassembled fluid power system component? 1. Identify the ring’s size and material 2. Inspect the ring for cuts, nicks,   and flaws 3. Install felt washers on both sides of the ring 4. Lubricate  the  O-ring  groove and  all  surfaces  over  which the ring must slide 3-66. What  is/are  used  when  the  O-ring installation  requires  spanning  or inserting  through  sharp  threaded areas,    ridges,  slots,  and  edges? 1. O-ring  expanders 2. O-ring  entering  sleeves 3. A rolling motion of the O-ring 4. A light coating of the threads  with  MIL-S-8802 3-67. What device is used to prevent 3-68. 3-69. 3-70. O-ring  seal  extrusion  under pressure? 1. Backup  ring 2. Cup  packing 3. Flange  packing 4. Gasket Backup rings made from which of the  following  materials  are  the most  widely  used? 1. Cork 2. Leather 3. Tetrafluorethylene  (TFE) 4. Bakelite What  is  the  age  of  deterioration of TFE backup rings? 1. 1 year 2. 3 years 3. 5  years 4. TFE  does  not  deteriorate When the packing in a fluid power system  component  is  being replaced,    the backup washers should  be  inspected  for  which  of the  following  conditions? 1. Fray 2. cuts 3. Evidence  of  compression damage 4. All of the above 3-71. Which  of  the  following  statements about a Quad-Ring is false? 1. It can be used at extremely high  pressures 2. It provides a seal in only one  direction 3. It eliminates the spiral twist  sometimes  encountered with  O-rings 4. It can be used as a static seal as well as a packing for reciprocating  or  rotary motion 3-72. Which  of  the  following  statements is  incorrect  concerning  U-cups and  U-packings? 1. They are usually made of different  materials 2. They both seal on the OD and the ID 3. They  are  interchangeable 4. They  have  cross  sections resembling  the  letter  U 3-73. What type of seal is least desirable  and  is  used  only  where there  is  not  sufficient  space  for a U-ring packing or a V-ring packing?   1. Cup 2. Flange 3. O-ring 4. Quad-Ring 3-74. How  are  O-rings  stored? 1. They are hung from pegs 2. They  are  kept  under  tension 3. They are kept in their original  envelopes 4. They are kept in a light, moist  atmosphere  with  a strong  draft 3-75. A  torn  O-ring  package  is  properly secured with which of the following  materials? 1. Staples 2. Moistureproof  glue 3. Outer  covering  of moistureproof  paper 4. Pressure-sensitive, moistureproof  tape 23