I've experienced several problems with lost keys in these gas caps.
In some cases the keys were lost when the cap was unlocked, which helps
a lot.
The lock is pretty rudimentary, with cross slats working ILO tumblers.
What I have done is to take them out and fit the slats I had to the key
I had and any I could not get to fit I discarded (although if one were
interested enough he could probably modify them to fit).
That somewhat reduces the "security" of the lock but most folx, even thieves,
don't carry around an assortment of WASO keys so they are probaby deterrent
enough that way. Volvos are pretty hard to siphon from anyway, even with the
best "Oklahoma credit card". What you really want to avoid is having someone
put other stuff in your tank, like sand, sugar, ethanol, etc.
--
George Downs Bartlesville, Heart of the USA!