Tabe,
  Thanks That is a good idea!
  I don't have an extra cap but when I order a new expansion tank it will probably come with one.  I have a Topeak bike pump, but am not sure I want to dismantle it for this?...(looking at it now)  Just checked and the inside diameter of the pump hose is very small 3/32".  Hum... It has an inline guage (not incremented type with dial), .  Could definalty work... but it's not that accuarte.  Will definalty keep it in mind, this cheaper way to go.

  Nate

Date:    Fri, 23 Mar 2007 12:41:23 -0400
From:    Tabe Johnson <greentabe-vanagon@YAHOO.COM>
Subject:
If you're a cheap bas... uh, I mean value driven like me,
you can gut a used cap to remove the valving and attach an
air compressor or hand tire pump to the pressure tank.  Apply
your chosen pressure (I'm thinking 50PSI is NOT a good choice!)
and look for leaks.  Beats the heck out of the $50 pressure
testers for sale.

tabe johnson/87 westy