View Full Version : What oil for bronze bushing?

08-15-2010, 10:07 PM
The who knows how old whole house fan we have (like this one)


started squealing a couple of days ago. Took it apart and found the shaft rides in what I think are bronze bushings. Everything was quite dry, no lube of any kind, although there was a felt wick that sat on top of the lower bushing. And an oil cup at the top that matched a hole in the felt.

What lube would I use for this? I cleaned it and used wheel bearing grease, but that only lasted for two or three days...


08-15-2010, 10:23 PM
Straight 20 or 30 wt oil is what I normally use YMMV.

08-15-2010, 10:44 PM
Ive used 15w40, warm the bronze with a pencil flame first, the oil gets sucked in better, i'm sure someone will elaborate, suppose you could warm the oil?
looking at the design of the register i'd guess late 70,s

Dr Stan
08-15-2010, 10:46 PM
either of the above will work as will 3 in 1 oil

08-15-2010, 10:53 PM
either of the above will work as will 3 in 1 oil
dam i forgot the old 3in1, i think the smell of that stuff started be off in engineering as a child

08-15-2010, 10:58 PM
either of the above will work as will 3 in 1 oil

Yup,put some Mint oil in it and you have $9.00/can Tapmajic too:)

08-16-2010, 08:04 AM
dam i forgot the old 3in1, i think the smell of that stuff started be off in engineering as a child

Yeah, that and WD40 are the stuff flashbacks to childhood are made of. Can't forget the ozone smell from the old B&D 1/4" single speed non reversable drill either :)

still has the drill

J Tiers
08-16-2010, 08:28 AM
I am partial to slightly lighter oil because it seems to penetrate the porous bushings faster and better. Most of those, if not all, would be "oilite" types.

If the old oil is really gummy or "dried", you may actually have to disassemble and clean with solvent, because the residual oil will block up the pores.

Mostly, with exhaust fans, there is an accumulation of dust/lint that ends up wicking the oil out of the bearings, particularly the bottom one, so the problem isn't "dried" oil but "no" oil. Then re-oiling works fine.

Saturate that felt wick, and put some oil on the shaft at the bearing also, for initial lube. When the bearing heats up in use, it will expel air and will then draw oil in from the wick when it later cools.

08-16-2010, 08:38 AM
It was pretty grimy with congealed dust and whatnot. I don't have the exact size with me, but McMaster lists bushings for about a buck each. I'll lube the wick and get new bushings and that should take care of it.

3 in 1 is what, 10 wt oil?

Thanks all.


08-16-2010, 08:47 AM
I can tell you what not to put on it. Nothing that has PTFE or Teflon. TriFlo is one example. It turns to glue in a year or so. It cost Xerox big bucks to find that out. Also, nothing that is "extreme pressure" rated such as differential lube. The extreme pressure additives are not compatible with yellow metals and will cause corrosion.

08-16-2010, 03:06 PM
3 in 1 makes an electric motor oil ( has a pic of a motor on it) I think it is SAE 20 Wt. Oilite bearings are lubricated with SAE 30 Wt. at the factory.

If you have a vacuum pump, make up a simple oil impregnator out of a mason jar. Soak an old dried out bearing clean in acetone, pop it in the jar and cover with oil. Pull a vacuum and you will be amazed how much air bubbles out of the metal.


08-16-2010, 06:30 PM
I just remembered I have a couple of quarts of 30wt non deterget motor oil, I think I'll use that instead of the 3 in 1.


J Tiers
08-16-2010, 09:08 PM
So long as they are standard replaceable bushings, you may be good that way....

Some are self-aligning, typically found in electric fan MOTORS, not separate shafts, and those often are non-replaceable, if only because you won't generally find the part anywhere, and because they are often spun or staked together.

Solvent works well, use a q-tip or a few of them, to clean the bore. Don't be stingy with solvent, more crud will ooze out if you keep at it.

08-17-2010, 07:08 AM
Go to local HVAC joint,look for........jandorf "original" Zoom spout.Its the right oil(some thin spindle oil)with a rediculously convenient telescoping spout.The bloomin thing stretches out almost 12".BW

J Tiers
08-17-2010, 08:19 AM
That's exactly what I use for small motors. The same stuff is available in many hardware stores (non-big-box) from "Sealed Unit Parts Co".

08-17-2010, 03:34 PM
This one.........Turbine oil. Just picked up two this AM at GE's parts store, ( was getting parts for a neighbour's stove.) $2 Ea. Have also seen those at HD.

Sealed Unit Parts Co.
P.O. Box 21
Allenwood, N.J. 08720

Part No. MO - 98

http://hotimg23.fotki.com/a/216_66/140_172/TurbineOil-vi.jpg (http://hotimg23.fotki.com/p/a/216_66/140_172/TurbineOil-vi.jpg)

08-17-2010, 04:34 PM
Chester,post a pic with the spout extended.BW

08-17-2010, 08:29 PM
Like so...........that "tit" next to the main spout is for storing that red cap when the "snorkle" is in use oiling, but it usually gets lost anyway. I find that extension too cumbersome most times and reduce it to about half length. (doesn't make any diff. until the oil is half used up)

http://hotimg23.fotki.com/a/216_66/143_9/ExtendedSpout-vi.jpg (http://hotimg23.fotki.com/p/a/216_66/143_9/ExtendedSpout-vi.jpg)

Edit: Pic taken about 8:15 Eastern time and already getting dark..............really goes downhill fast once you hit Aug.

08-17-2010, 11:52 PM
I have and use that zoomspout oil- seems good. One thing about it is it's thinner than motor oils and will have a better chance at penetrating the pores in the bushing. That takes time, but it can work out. If you can get the motor apart with reasonable effort, it would be even better if you could re-impregnate the bushings from the inside. You're not likely to be able to remove the bushings from the end bells, but you can use a bit of a redneck technique to do this. All you need is two circles of rubber sheet that you can squeeze against the ends of the bushing.

One way to do this is to clamp a short piece of wooden dowel upright in a vise. Put one rubber disc onto it, then lower the end bell onto that. Hold it there to make the seal at the inner end of the bushing, then fill the bushing with oil. Lay the other rubber disc over that and press with a finger or thumb. You'll be squeezing the oil into the pores, and it will eventually soak into the felt washer. Once that happens, you'll basically have a reservoir of oil there to lube the bearing for years to come.

You might be surprised at the colors that come out as you re-dissolve what was left of the original lube. I like to inject enough fresh oil to get rid of much of the old stuff, then leave it at that.

I know you'll be able to squeeze the turbine oil through the pores- it seems like about a 10 wt. I'd say use between a 10 and a 20 wt, personally I wouldn't go thicker than that.

08-18-2010, 07:36 AM
The Zoom oil is what I use for the oil cups on my Bridgeport spindel and all the electric motors that have the oil cups. I have been using it for years and believe it to be a good quality product.

08-18-2010, 08:29 AM
That is very good oil. The reason it is called "Turbine oil" is because it was originally formulated for lubricating the bearings in clothes dryer air turbines. They run very hot and the oil is formulated to be as non-volatile as possible so that it won't gum up.

08-18-2010, 08:35 AM
I am able to get the bushings out of the sleeve that they press into. Monday night I removed them, and gave them and the shaft that runs through them, a once over with xylene and a toothbrush. A bit of schmutz was cleaned out, but not as much as I was expecting. Soaked them and the felt wick in 30 wt non detergent motor oil and put it all back together. So far, so good <knocking on all the wood I can find> :D .

With the weather we've been having here in NY, we've had this fan running pretty much 24 hours a day. It does get shut off for a half hour or so when someone takes a shower so it doesn't suck the fumes from the furnace (our water heater is internal to the boiler) throughout the house.


08-18-2010, 09:37 AM
'Splained on another post about "Oilites", small can of oil, drop bearing in and heat up, allow to go cold, remove bearing, drain exess and refit. First alternative if you don't have vacuum eqipment.

Regards Ian.

08-18-2010, 09:47 AM
It's best not to use WD40, 3in1 oil or detergent engine oils because they have additives that will cause gumming. You should use an oil with no additives such as Zoom, gun oil or motor oil that is made for electric motors. I buy motor oil from the hardware in bottles like the Zoom is in.

Be careful of using any oil with additives in it.

08-18-2010, 09:55 AM
The reason it is called "Turbine oil" is because it was originally formulated for lubricating the bearings in clothes dryer air turbines.

It's much older than that. It's called "Turbine Oil" because it was designed for steam turbines. I posted a 190x brochure here from Standard Oil advertising their DTE "Turbine Oil", I'll see if I can find it on my Photobucket account.

Edit: Found it. It's the Gargoyle Oil Company, a subsidiary of Standard Oil, that became Mobil. The "DTE" in the Mobil DTE hydraulic oil we use in lathe headstocks today is the modern variant of the Turbine.Engine. oil from 1902 :)