Trailer hitch question/Compressor issue?

[5B Steve]

   I have a couple of things that I need to ask, (1) How hard is it to put a hitch on my MCI-5B and can it be

   done, and are, all the back bumper areas the same on the A'S B'S and C'S?  Secondly, I've noticed a

   strange ticking sound coming out of the compressor, almost like a "CLACK, CLACK , CLACK  if that makes

  any sense. Is there a problem in the future?

   Steve 5B....