> Has anyone ever dissembled or repaired a distributor vacuum advance unit?
>Mine has a leak and I really hate to part with $50-$60 for a new one, when
>the only problem is a tear or rip in a rubber diaphram. Can these things be
>resurrected? Has anyone done it, without trashing it?
Are you sure the rubber diaphram has a hole? Or are you just assuming it must
because it leaks. In my own experience and observations of vacuum diaphrams,
the rubber is some magical nearly indestructable form. And unfortunately never
used inside carburetors, where their diaphrams self destruct quite rappidly.
Anyhow, what I've noted is that usually it's the shaft and or seal that dies
instead. I've successfully built up ignition advance/retard shafts using
aluminum foil. Cutting it carefully with scisors for a smooth edge, wraping
and burnishing it for a while with my thumbnail. Then seeing if I've got it to
the right diameter by fitting it. Takes a few pieces to get the length right.
Properly burnished around the shaft, the stuff says in place. Probably helps
that the distributor vacuum advance isn't a gizmo that goes flailing back and
forth mind you. If it's the seal, a trip to the hardware store and a pawing
around in their plumbing seal sections gives one a nice variety to experiment
On the off chance that it really and truly is the diaphram, I strongly suspect
you could use a good tire patch kit on it. Not the cheesy cheap things one
at K-mart that use rubber cement and a big chunk of rubber, but one of the
vulcanizing kits, that have a very thin feather edged patch, and use heat to
and cure it. Again though, I have not ever personally done this.
>I suspect the durometer (softness) of the rubber is important, so it moves
>at the right pressure, but I'm not sure.
Doubt it. There's a pretty hefty wire spring inside the vacuum advance unit.
That's what controls the motion. A stiff section on the diaphram wouldn't
the force against that spring from engine vacuum.