I solved the leak problem in the on/off valve by removing the whole
unit.  (Lives under the rear bench seat)  Fortunately a friend of mine who is
a real mechanic was present, so the bypass was done elegantly with two copper
elbows and a straight piece with a bleeder valve.  Theory is air will end up
here since this loop is the highest point in the coolant pathways; hence the
bleeder valve.
   Anyone want to buy a functioning rear heater with a leaky valve?  P-mail
me.
     Is anyone else on this list also a Volvo owner?  Or REALLY masochistic--
as in MG?  Check out the swedishbricks site.
Carol S Sussman
"Not a mechanic; just a driver with a toolbox"
1981 245 Volvo
previously '68, '71 MGBs  in SCCA hillclimbs.  Heard in pit row from beneath
the car (in the rain, of course)  "Are we having fun yet?"