> When looking at the
> filter I could see a bit of the gasket poking out between filter head
> and cannister.
Meaning the edge of the canister was above the edge of the lip/groove on the
filter head ?
> Just inside the rim of the filter head there is a seat
> for the gasket, and when fitted there is only a tiny distance, maybe
> a millimetre, to the edge of the lip.
Right, the edge of the gasket is below the lip, and will compress even more when
the canister is tightened, forming an enclosed space to compress and contain the
gasket in all 4 directions. This is necessary because the gasket has no
structural integrity of it's own, and the force against it is considerable.
> I put a bit
> of grease on it to hold it in place in the filter head, and then
> advanced the cannister with new element, up with the bolt until the
> whole thing was fairly tight.
Did you check that the canister entered the groove ?
> Question: Should I have bolted the cannister up until it was really
> tight against the gasket, or should it just be basically finger-tight
> like modern screw-ons?
Well, you definitely can't hand-tighten it like a modern screw-on, you have to
turn the bolt head not the canister body. The book torque spec is 18-20 ft-lbs,
which I would call moderately tight. If you don't have a factory workshop
manual, you should get one (or a Bentley reprint). The bindings on the original
manuals tend to fall apart ... there are falling apart but complete (thus
usable) ones on eBay from time to time for as little as $10. I didn't find one
at the moment, but here's a reprint that might go fairly cheap :
> Or otherwise what did I do wrong?
My first guess is that you didn't have the end of the canister located into the
groove in the filter head.
However, another common mistake is to have an extra gasket in the joint ...
possibly there from before or even many times before. Take out all the gaskets
you can find, then clean the groove with carb cleaner, rag & screwdriver, then
examine it under a strong light. You should be able to see silver at the bottom
of the groove. If it's black, even shiny black, chances are you're looking at
another gasket. Takes a sharp probe (dental pick) to dig out a really buried
gasket. I've even had to break them into pieces to get them out.