On Mon, 5 Oct 2009 13:21:54 +0000 (UTC), Andrew Gabriel wrote:

In article ,
"Doctor Drivel" writes:

"Andrew Gabriel" wrote in message
...
I was given a second-hand Xpelair which is 30 years old. Ran
continuously for 10 years before I got it, and I've used it
during the summers since. This year, it started seizing, being
slow to start up. I cleaned and oiled the bearings and it worked
for several more months, but is starting to do it again now.

Would synthetic high melting point grease be better on the fan bearings?
Although buying this sort of grease is not cheap.

Bearings don't get hot, and I suspect they need a low friction oil.
They're lubricated by a tiny amount of oil in the phosphor bronze
(or on some, just by a high lead content phosphor bronze alloy).
I think the problem is caused by dust eventially getting into the
bearing. Cleaning this out helps, but it has scored the shaft.
Only oil I have to hand is (clean) engine oil, and I suspect that's
much to viscous to be absorbed into the bearing surface.

Last time I replaced a plain bearing it needed oil as it was dry. Doing it
at work enabled the use of vac. pump - amazing amount of air came out -
then let atmospheric pressure push the oil in.
This method might not be possible at home, but heating the oil with the
bearing in it (poss. 70 - 80C should be OK and not damage anything) then
letting it cool would get a lot more oil in to the bearing.
Assuming that the bearing can be removed - not a good method if not.
--
Peter.
The head of a pin will hold more angels if
it's been flattened with an angel-grinder.