Howto : Fixing old case fans

[LSDsmurf]

[Guest]

LSDsmurf, nice tip, but unfortunately, by the time the bearings start making noises, lubricating them is a temporary fix at best.

[Guest2]

Umm, I've done this same thing a half-dozen times but I dont think spraying oil all over the magnet is all that great of an idea.
When the fan spins up inside your case the oil will get slung out onto the inside of your case.
I don't really think that's needed anyways considering that new ones don't have oil on 'em.

[Guest]

Hi!

I have found that cleaning my own fans was a nice idea, but poor in practice. Buy good quality fans to begin with and you won't have to replace them as often.

This is a nice idea, but it does not really work, and chances are that it is not worth your time anyway. I say this from experience. I have tried cleaning fans several times and it really does not work that well, it requires a lot of time, and you make a big mess.

One of the more significant problems is lubricant. Oil and dust makes for gunk that will just clog up your fan again very quickly. Graphite would work as a lubricant in this situation, for the same reason that it is used it locks. However, once a fan goes off balance, there is not much that you can do other than replace it.

I can not recommend that anyone actually do this. Of course, if you the type to pay a few more dollars for an orange fan and are going for the rice-boy of computers look, you might have different priorities than using your computer to actually get some work done. No offence or anything.

[Low_E]

hi dudes,

nice try but the alication of oil will indeed be very temporarely...
besides, putting or spraying some on the magnetic circle is of no use at all, since that part, IMHO, doe NOT make contact with the bruches.

It is the axe that should be taken care off. So , I guess, when you sprayed some oil around, you sprayed on the axl also and that helped indeed, but only for a short period of time.

This is what I do: in stead of oil, I use ballbearing grease, the kind of stuff you put into ballbearings for skates and so...
I noticed that the fan will drop some in rpm but will perform much more quite .. and for a much more longer period of time.

I just put some on the axl and in the axl-hole (I do not know how you call that in english, i'm dutch-speakin)

Anyone, I invite you to try this and give constructive critic.

ps: I have done this on several fans, about ten or so, never had a problem about not running. I once had a little fan (vga-card) that, after applying some of that grease, wouldn't turn, because of the increase of contact within... so i helped it starting by giving it al little push with my finger several times. After a minute it was running slow but constant... now, some weeks later: smooth as before and more quite.

ps 2: Again I say this: this is never a permanent solution, but it will last for months!!

[Nighthawke]

I hate to shoot you down, but your lube is Wayyy too thin to do the job...
What I use on brand new or used fans is good old fashoned Lube Gel from the local Rat Shak (Radio Shack), or a medium viscosity moly.

I strip the fan down as what he has posted, but I leave the magnets alone for they do NOT rub agianst anything, and if oil does get in there, the ring would try to slip and make the fan get out of balance.

I simply take a toothpick full of lube and put a dab the size of the end of a cotton swab, then a dab at end where the shaft meets the fan, finally putting it back together. Reassembling the fan with the lube on the end ensures that the bearing races get a even amount of lube on their wearing surfaces and the shaft simply rides on the cushion of lube as it runs.

The little keeper is optional for the magnetic forces keep the fan blades in place, and the free motion ensures a even wearing and lubrication of the races.

Using this method on brand new fans, i've yet to have to replace a fan due to badly galled bearings or seizures.

As for ball bearing units, i've no idea about how to deal with them, since the races are sealed. If they are tampered with, would introduce dust into the assemblies and shorten their lifespan.

[LSDsmurf]

Yes you're right, it's only a temporary solution, but it could help you for a few weeks or longer.

And by the way, Low_E thanks for the tip.
_________________
DarkVision Hardware
http://www.dvhardware.net

[Guest]

oh my god,,,, JUST BUY A NEW FAN

[scalar@jpj.net]

Oil and sleeve bearings absolutely do not work well together. I found this out the hard way years ago with a vacuum cleaner motor that had sleeve bearings.

Sleeve bearings are zero-maintenance bearings. They are supposed to be oil-free. Oiling them will in fact lead to premature failure and possibly even a bearing locked so tight you will never be able to remove the shaft from the sleeve again.

A sleeve bearing is amazingly simple. It consists of a hard metal shaft (like steel) that sits inside a soft metal ring (like brass). I don't understand the actual principle, but they do not wear over time, even with no oil in there.

The actual cause of sleeve bearing failure is dust. If you used a sleeve-bearing fan in a completely dust-free room it would likely run for years 'n years without trouble.

However, in normal use, dust works its way into just about everything inside a computer. In time it even manages to get into the sleeve bearing, which as you can see in your pictures is way underneath the fan rotor.

The clearance between the steel and brass is very very small. The clearance is in fact so small that the dust actually gets wedged between the two metal surfaces.

When the fan motor spins, that tiny very hard dust grain (likely a piece of rock dust) rolls round and round in between the two pieces of metal. It is rolled along by the moving steel shaft on one side and the stationary ring on the other.

The steel is unaffected by the dust, but because the brass is soft, the pressure of the dust grain on it digs very small furrows in the metal. If the dust grain happens to spin round and round in just one spot, eventually it will dig a very large furrow in the brass.

As I mentioned the clearance is extremely small, so when the brass has these furrows created, the ridges of brass press tightly against the steel shaft, creating a lot of friction. Over time this friction produces a lot of waste heat, and the force required to turn the rotor greater and greater until the fan motor can no longer overcome the friction. Through all this, the rotor slows down until it can no longer even get moving anymore.


Spraying a lubricant into a sleeve bearing helps... for a while. Yes, for a time the lubricant helps the steel glide over the brass furrows more easily, and the rotor now spins easily.

However, those brass furrows have not gone away. They are still there, still pressing on the steel shaft, still creating friction.

So even though the bearing turns somewhat more freely again, it starts to heat up again. But before it was just metal-to-metal contact, the sleeve and shaft could get extremely hot in a very small focused area without any major problems.

Now, however, we've got this oil in there. And the oil has something called its breakdown or cracking point which only occurs when it gets extremely hot. This is where the carbon bonds collapse, and that thin slick oil now suddenly transforms into a thick tar-like goo that smells like it has been burned (it has).

This thick goo will burn and decompose at those tiny regions where the brass is rubbing the steel, and it will greatly increase friction. In fact, it may very well glue the two metal surfaces together, and lock the two metals together so tightly that there's no way you're going to be able to take it apart and try to oil it some more.


Next step, throw the fan away.


-Scalar
scalar@jpj.net

[Guest]

More than a few old PCs used fans that can't easily be replaced today, and a drop of good, light oil on the washer can stall fan death long enough to order in the specialty hardware needed to get your machine running properly (I live in a smallish town where NOBODY carried Slot coolers when my P-II bolt-on HS/F did the howling thing). Don't bother disassembling the thing, though. Just lift the sticker and the little plug, and put a few drops on the washer. Spin the fan and watch that oil suck into the bearing area. BTW, my understanding of bushings was that they are a semi-porous metal that contains oil (sponge-like) and they die when the oil escapes, evaporates, or burns; I have fans that have run for years after the oil treatment. Isn't this why Papst has a serpentine oil-catching bushing design that competes with ball bearings for durability?