Dan,

This is an easy job.  You can use a couple of C-clamps with small blocks
of wood to pinch the hoses.  However, I just discovered a new (to me)
tool at my FLAPS (NAPA) called a "hose pincher"!  This is a ratchet
locking device that looks like a pair of pliers with wide swiveling jaws
to grab the hose.  I couldn't resist, I bought two of them for $18 each,
and they are great for the Vanagon, a real time and coolant saver.  They
are NAPA's Pro Line of tools if you are interested.

I have replaced this valve without needing to bleed the system.  Just
check the overflow reservoir daily for a few days and top it up, the
system will usually bleed itself of small bubbles.

Have fun!
--
Stuart MacMillan

'84 Westy
'65 MGB
'73 MGB GT