On Jul 19, 6:56*pm, Jeff Liebermann wrote:
On Sun, 19 Jul 2009 17:42:43 -0700 (PDT), Robert Macy
wrote:
This may not be a clutch by design, but rather a rubber 'alignment'
shaft. *When new, the press fit kept the fan and motor locked
together, but with age and rubber deteriorating from actions of oil,
the press fit is slipping. *Now to lock the fan to the motor shaft???
Thank you all.
Should I use super glue on the rubber?
No. *Superglue is brittle and will crack loose the first time the fan
hits something. *Start by tearing the rubber shaft (clutch?) apart and
cleaning it and the shaft. *Remove all the old oil and goo. *Use
alcohol to make the rubber swell a bit. *Make sure the shaft is clean
and oil free. *There should be enough friction to make it work. *If
not, try some rubber belt no-slip compound used for improving the
friction in tape recorders, record players, and other rubber parts.
Avoid xylene (dimethylbenzene) based "rubber restorer" solutions as
they will soften the rubber but also probably make the shaft slip.
For high temperature lubricant, use a SOLID lubricant, not liquid.
Yeah, I know it doesn't penetrate, but that's the price you pay for
high temp. *See:
http://www.tribology-abc.com/abc/solidlub.htm
for clues on different types. *If you're lazy, try graphite lock lube
(the powder variety, not the messy stuff mixed with light oil). *Keep
the lube away from the rubber "clutch" as it will make it slip.
I do some HP LaserJet printer repairs. *The older models (LJII, LJIII
and LJ4) required some grease on the drive gears and a few metal gears
on shafts. *When needed, I used lithium white auto grease, which is
probably not the right stuff, but worked well. *However, all the other
nylon gears were self lubricating. *The best way to make a huge mess
was to lube all the gears. *I'm not 100.0% sure, but I believe that
current HP printers (LJ42xx, 43xx, etc) do not require any
lubrication. *I sometimes use "rubber restorer" on the paper feed
rollers, but only if the paper is slipping and I don't have a
replacement roller or foot.
--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558
Thank you for your reply. Great suggestions. Especially the rubber
belt dressing to increase friction.
The 'light grinding' noise comes when the motor shaft starts slipping
in the rubber transfer to the fan. It seems there are four small
ridges on the metal to help 'bite' into the rubber. So, when it
starts slipping it makes a noise.
Here is the failure scenario to date:
System does run fairly cool at around 60C [This is based upon my
experience at not being able to hold my finger on metal above 60C for
more than 10 seconds]. All bearings are smooth and oiled, also
running cool. Fan whether hot or cold turns easily coasting slowly to
stop. Oil however migrated from the motor bearing, along the shaft,
and into the rubber transfer and that is now slipping.
I tried to remove the fan from the motor shaft, but could not. I
completely lifted the motor/fan out of the unit, yet the rubber won't
slide off the end of the motor shaft allowing access to clean all
out. If there is a retaining clip of some kind, I can't see it, and
worse, not be able to get access to it. Since the fan is squirrel
cage, there is no way to gain access to a clip inside the 'cylinder'
with my tools.
Can I still try cleaning with alcohol? Will that dissolve any of the
oil residue inside the rubber/metal junction?
Change of subject: Not for this problem but for other 'clean out old
oil' problems, did you ever try transmission fluid? I once had a
mechanic tell me "to flush an oil system with one quart of
transmission fluid mixed in the oil to remove all the ill effects of
someone using STP. He said, don't drive it, simply heat the engine up
and change the oil mix out, and replace with oil, heat up engine
again, and replace with oil. That will clean all gunk out."
But, transmission fluid is a high temperature oil isn't it?
Robert