Gavin,
There is a Liquid grease out of an aerosol can that blows in "wet" and
dries to a greasy sliding substance.
Good for this sort of application, as it will spray in deep into the
cable, and linkage, and dry to a slippery grease.
Especially good to prevent corrosion in the area where you live.
Kar products has it available, but so should most FLAPS.

Later,

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Terry--
74 Campmobile- (Clementine)
85 GL- (Delilah)
86 BMW 325 ES- (Eva)