A while back, Erik asked about fuel sender units:
  "Is there any way of testing it before I reinstall the whole tank?"
 
  I expect the normal electrical continuity through movement range test 
was related to ALL, but a nice trick that should be used when it applies 
to high milage vehicle designs, is to flip the wire wound resistance 
sensor coil over before the mobil contact paw abrades all the way through 
any of the wire wraps. This generic approach applies to hundreds of 
vehicle designs and doubles their effective life.  On some, just bending 
the contact paw so that it rubs the coil in a different arc will do.  The 
idea's the same: Don't let it wear all the way through any single wire 
wrap, and it will keep on serving you well.
  Hope this helps someone.

  John Wakefield