TM   1-4220-250-12&P 4.8  REPAIR/REPLACE  LRU-18/U  COMPONENTS. 4.8.1  Cementing  the  LRU-18/U  Life  Raft. This  task  covers:  a.  Inspect b.  Repair INITIAL  SET  UP Materials/Parts Roller,  Wooden Disposable   Brush Toluene (Dl4) (D2) (D20) General  Safety  Instruction Adhesive Talc,   Technical (D1) (D17) Do  not  use  toluene  near  open  flame,  heat,  or  electrical sparks.  Avoid  prolonged  contact  with  skin  or  breathing  of fumes.  Use  only  in  well-ventilated  area. NOTE h. Replacement  of  easily  removed  assembly  components such  as  CO₂  inflation  valves  is  authorized  in  addition to  repair  and  replacement  procedures  documented  in this  section.  The  life  raft  shall  be  subjected  to  a  func- tional  and  leakage  test  each  time  CO,  inflation  valves are removed and replaced for any reason, and each time  inflation  valve  gaskets  are  replaced I. j. k. 1.  Determination  of  Reparability.  The  LRU-18/U  life raft  shall  be  considered  beyond  repair  for  any  of  the following    reasons. 2.  Cementing  the  LRU-18/U  Life  Raft.  Cementing  of the LRU-18/U life raft shall be performed as follows: a. b. C. d. e. f. g. Porous fabric areas on tubes. Split or open tube seams. Leakage  test  failure  resulting  from  other  than repairable  cut,  tear  or  puncture. Holes,  cuts,  tears,  or  punctures  within  I  inch  of tube  seams. Damaged,   malfunctioning,   or   excessively corroded  inlet  valve,  manifold  assembly,  oral inflation valves, or oral inflation tubes. Holes  or  abrasions  exceeding  1  inch  in  length  or diameter on tubes. Oral  inflation  or  inlet  valve  stem  separating  from the  fabric. Deterioration  of  the  nylon  fabric  caused  by  oil, grease, or any other foreign substance. Deterioration  of  the  nylon  fabric  caused  by  an excessive   mildewed   condition. Patches   exceed   three. Determination  by  an  ALSE  inspector  that  the  life raft  requires  excessive  repair. a. Place  life  raft  on  a  clean,  flat  surface. Ensure  repair  area  is  free  of  foreign  objects. Do not use Methyl Ethyl Ketone (MEK) to clean the  LRU-18/U  life  raft.  MEK  will  break  down the  polyurethane  coating  on  the  inside  surface  of the  raft. b.   Clean  both  surfaces  to  be  cemented  with  four applications of toluene. Apply toluene (D20) with back-and-forth  strokes  on  the  first  and  third applications  and  one-way  strokes  on  the  second and  fourth  applications.  Allow  areas  to  dry between   applications. GO  TO  NEXT  PAGE 4-16  Change  1