Apparently Crewfit experienced a quiet little problem with their vests, which they became aware of in 1994. The oral inflation tube was bonded to the vest (i.e. thermally welded) but the material of the tube was unstable and the inflation tube may simply UNbond, resulting in a total failure of the vest.
If anyone out there has an older Crewfit vest (pre-1994) you may want to contact them and find out if yours is in the unreliable group. Crewfit's policy on these will depend on your negotiating skills. Understandably they do not want to repair them. Other PFD's of a similar vintage may also be suspect if they used valves from the same supplier.
One more reason to check your safety gear
(even the old reliable top-name gear) regularly.