Thread Number: 40929  /  Tag: 50s/60s/70s Vacuum Cleaners
Working on vacuum motors?
[Down to Last]

Vacuumland's exclusive eBay Watch:
scroll >>> for more items
Post# 434713   11/8/2020 at 15:06 by fan-of-fans (USA)        

fan-of-fans's profile picture
Do you all take apart/work on vacuum cleaner motors? I have never done so, I just take the machine apart for cleaning, and blow any dust out of the motor/fan openings, but I don't take motors apart. Regular portable fan motors I can usually figure out for cleaning/lubricating, but vacuum cleaner motors with the brush/armature I don't touch. I once took apart a Hoover Helpmate hand vac and I tried to clean the motor and I ended up breaking the brush holders and ruined it. Somebody probably could have fixed it but I didn't know what to do with it.

I do wonder sometimes what I'll do if any of my machines ever need new brushes installed. I just don't take them out for fear of breaking them.

Also I think most vacuums use grease instead of oil in the motor bearings? I don't know how to work on those either.

Post# 434714 , Reply# 1   11/8/2020 at 16:14 by electroluxxxx (Somewhere out there)        

electroluxxxx's profile picture
there are actually quite a few of us on here who work in vac shops, I work in a the repair shop of a rainbow distributor doing all of the repair work, but that doesn't mean I only work on rainbows, I work on all kinds of stuff in my spare time from Hoover, Electrolux, Kirby, Kenmore, fantom, Airway etc... the list goes on and on, but the truck doesn't just stop at vacuum cleaners, I have experience in washers, dryers, dishwashers, and other types of large appliances. as for motors, when it comes to bearings you want to oil sleeve bearings, and grease ball bearings. By taking things apart you already know that all motors are different, different in the way they work, different by design and all use different types of screws, fans, springs, carbon brushes, armatures etc... As for you servicing your own motors in the event of failure its all about learning, and I am sure that you will be able to pick up on it pretty quickly by watching others and also I am sure that parts can be sourced by just asking for them right here as I have helped several members by sending parts out or sourcing them. I am also certain that people here will be more than happy to walk you through the process if need be as I have also made facetime calls and tutorials for other members who needed help in fixing their machines. The one thing that I have learned over the years is that " everything is prone to failure" regardless of how well it is made, how old it is and how long it is supposed to last.

Post# 434715 , Reply# 2   11/8/2020 at 16:20 by gottahaveahoove (Pittston, Pennsylvania, 18640)        

gottahaveahoove's profile picture
There are several videos on this. I have detailed photos of Hoover cleaners being serviced. But, I'm only Hoover.
Just be careful with oil vs grease.... what, when, where, etc.
Best of luck with your project.

Post# 434717 , Reply# 3   11/8/2020 at 16:44 by Lesinutah (Utah)        

lesinutah's profile picture
Automotive electrical cleaner. There is no power to the motor so you can spray it down with soapy water. You have to be careful with what you use on it. You have to make sure the motor(armature) is dry before re-installing.
The field coil you can spray with the same electrical cleaner or soapy water. It has copper and sends the power to the switch. I put my armature in the collet of my drill and make sure the fan blades are square and it spins good. I use contraries stone on the commuter. I then blow off the dust from the stone. You can spin on the actual fan check it for balance.
I know you can do more than I said but I don't know what or how. I keep it simple. It doesn't hurt to have a clean motor.
There are tests you can do to check to see if the motor is good. It's on you tube.
I did take off a piece soldered onto the field coil. I'm pretty sure a professional installed them. I put everything back together except the motor housing shell. I pushed the power button on and a spark I turned it off. I looked and I thought maybe it's burning off something. I turned on again. The carbon brushes got stuck and quickly a small green spark and then purple. In short the part I took off helped the motor run. I took it off and basically the vacuum motor armature and coil melted. I had another motor I was testing. I didn't realize I didn't have the right coil on to match the armature. Kirby had company A make motors for do 50 and ds80. In DS 80 production run Company A stop making motors. Company B started making motors. I put company A armature with Company B coil. I'll be damned this melted too. I watched in disbelief as my second unit burned up everything.
It was my first major restoration. I had a few months into it. I cried a little in shock. I learned quite a bit.
You can make the nicest shiniest vacuum. It can be up in smoke. I have exploded views of 505 to Avalir. I never mess with the motor or coil other than small cleaning.
I don't want you to be like oh I'm not touching the motor. I'm just saying just clean the motor and be smart.
Green is copper burning blue and purple are the other metals melting. I'm a plumber now and watch copper get heated up every day. I asked the journeyman why it was green. He told me its copper heating up. Copper has to be 1200 degrees. I'm the apprentice and I prep everything and he uses the torch.
I'm still timid with the torch. I'm watching and learning.

Post# 434728 , Reply# 4   11/8/2020 at 19:03 by Dysonman1 (Rolla, MO)        

dysonman1's profile picture
I learned how to take apart and reassemble motors many decades ago. Started by repairing one of the hardest there is, rainbow motors. I can now work on any motor that can be taken apart.

Post# 434729 , Reply# 5   11/8/2020 at 19:59 by huskyvacs (Indiana)        

huskyvacs's profile picture
Cleaning up a vacuum so much defeats the purpose and is a wasted exercise if the motor has been run into the ground or never repaired. It's like polishing up an old barn find car to concourse level quality but the engine is seized up and cann't run.

Motors are relatively easy to repair. If the armature needs to be rewound - leave that to a pro. But 99% of motors just need to be washed, new grease, polished, and new brushes.

There is special grease for electric motors as well as a polishing stone.

Just find a good video on YouTube that is not clickbait or fake junk, and also look for old handyman books that detail motor repairs.

Start with a simple vacuum with not a lot of features that also isn't rare or expensive to get a feel for it. One that has a simple easy to understand motor. Once you get into newer and premium vacuums with multiple motors. multiple statge motors, overload protection circuitry, stall protection circuitry, all that stuff, that is too daunting for a beginner.

I would recommend finding an old Shop Vac to practice with. The motor is very simple and basic, easy to get to, and they are always guaranteed to have bad bearings or a horribly worn out motor in need of an overhaul.

Post# 434738 , Reply# 6   11/9/2020 at 01:15 by MadMan (Chicago, IL, USA)        

madman's profile picture
But breaking stuff is how you learn how to not break stuff...

Post# 434740 , Reply# 7   11/9/2020 at 02:41 by tolivac (Greenville,NC)        

I deal with motors as well-from tape decks to transmitter pumps and blowers-those are LARGE motors--5-20Hp!Usually bearings.If the large motor here needs rewinding-rebuilt-it is sent to a motor shop.My hard rule----if the motor WORKS properly-----LEAVE IT ALONE!!!!!!!!Enjoy it!!!Too many folks tear down working motors to clean them-then get befuddled when it becomes time to put it back.I have a working 1930's GE vacuum I found at Restore-Works like new!!!!I am leaving it alone and enjoying it!

Post# 434755 , Reply# 8   11/9/2020 at 13:19 by Real1shep (Walla Walla, WA)        
What you really......

need is an Elmer(mentor), the first few time you rebuild a motor.

And hopefully, you'll find someone that does it correctly and efficiently.

There are a lot of vids on YouTube for rebuilding small electric motors that apply. Trouble is many of them are trash. And once you start out with bad habits.....

Mike gave a decent primer don't have to find someone in your area that just works on vacuums.....anybody that's good with small electric motor repair can mentor you.....especially someone close to retirement(like me), or retired.


Post# 434774 , Reply# 9   11/9/2020 at 22:20 by MadMan (Chicago, IL, USA)        

madman's profile picture
toli - You'd be right for most things except motors with sleeve bearings - especially old ones. Cuz let's be honest, nobody ever oils them. So I would always take them apart if for not other reason than to make sure they are plenty oiled. And then you gotta remember, most of those are sintered bronze bearings, and if they've been run (truly) dry, no amount of oiling will make them take oil again. They need to be forcefully oiled. Which, you know, most people aren't gonna do.

Post# 434777 , Reply# 10   11/9/2020 at 23:57 by kirbyklekter (Concord,Ca.)        

Is the advantage of sintered bronze bearings because they require less maintenance? Are they still oiled the same as if they weren't infused with oil? Billy

Post# 434782 , Reply# 11   11/10/2020 at 06:50 by Real1shep (Walla Walla, WA)        
There are....

two types of sintered bronze bushings;dry lubricated and wet lubricated. One is impregnated with oil and the other is impregnated with dry lubricant like graphite.

The dry lube bearings can't be just converted to run wet with oil simply by adding oil to them. You have to chem strip them down and as MM says, force oil into them.

There is an easy way to force oil a sintered bronze bushing;you can force oil into them with your thumb and forefinger. It's a simple process wherein you hydraulically force oil into the bushing from the inside until you see it bleed through on the outside. I believe there is a YouTube vid of someone doing just this.

Sounds crazy, but it works great. Early electric motors had a wick next to the bronze bushing. You saturated the wick so it continuously fed oil to the bushing. Only problem with that system was that most people never cleaned and rejuvenated the wick.

As far as re-lubricating a dry sintered bronze bushing, I have no worthwhile method.


Post# 434790 , Reply# 12   11/10/2020 at 15:30 by kirbyklekter (Concord,Ca.)        
@ Kevin

Thanks for explaining that. Can you tell me what would be a good indicator that a bearing is a sintered bearing appearance wise.Other than a possible wick, is the metal more porous?

Post# 434799 , Reply# 13   11/10/2020 at 22:12 by Real1shep (Walla Walla, WA)        

is a term for a bronze bushing(and actually other bronze devices) that is porous. In this instance it refers to motor bushings designed to cup a steel shaft end with lubricant.

It's difficult sometimes to tell a impregnated wet bushing from a dry bushing if they are both old in service. As I said, I know of no reliable way to re-impregnate a dry bushing with dry lubricant. Therefore I make them all wet bushings.

In answer to your question, if they are bronze in color or dark bronze, they are sintered bronze bushings. Other than ceramic, you won't see any other type of bushing cup in routine small electric motors. The idea is that the bronze will wears before the steel shaft.

Don't assume that all bronze bushings can be saved and lubricated....some, if run long enough without sufficient lubrication, will have too much play around the shaft. Not the end of the world though because bushings are out there.....although more and more of them are dry impregnated.


Post# 434807 , Reply# 14   11/11/2020 at 01:49 by MadMan (Chicago, IL, USA)        

madman's profile picture
@kirbyklekter - Kevin's explained it pretty well. Though, to be honest, I don't think I've ever seen a dry lubricated sintered bronze bearing. I know they exist, but I think for most common applications like vac motors, they're gonna be just oil lubricated ones. I dunno, maybe newer designs are moving over to dry?

Anyhow, I personally would have trouble telling a sintered bronze bearing from a solid brass bushing / bearing, by color. Especially given that they're usually dirty after being in service. If you clean it off, you can actually tell the sintered ones are, well, sintered. They have a unique textured color / appearance, as opposed to a solid brass metal, which would have a uniform color.

The real giveaway is the lubrication method. A solid bearing has no way of getting oil to the spinning shaft on its own. So, it would need a method of getting oil directly to the shaft, like an oil wick or ring oiler that touches the shaft directly. Which requires a hole in the bearing. This is generally the case for very old motors, and for not so old, but heavier duty motors. For example, my Eureka model 10 (~1927) has solid bearings, thus it has holes drilled through the bearings, and a oil cup underneath each with a wick that go up through the hole to touch the shaft.

Whereas a sintered bearing is effectively a metal sponge, so it has its own oil IN the metal. These will (hopefully) have an oil wick or - more commonly - felt to hold some extra oil, but that will NOT directly touch the shaft, only touch the outside of the bearing. That's the giveaway - whether the oil wick or felt touches the shaft or not. It's often the case with cheap, small C-frame motors that they have no oil felt at all. Now, I suppose some of those would hopefully be dry lubricated, but I think the reality is that they're built so cheaply, that the oil in the bearing is considered good enough for the 'lifetime' of the motor - which will be like 5 years. Anyway, as the oil is used and pulled out of the bearing, the extra oil in the felt will get capillary-action-ed into the bearing. But see, that can only work if there's still oil in the bearing. Once it's run dry, it can't take new oil on its own.

Fortunately, you can put the bearing in oil, in a vacuum chamber, and suck the air out. I've forcefully re-oiled quite a few, it seems to take several hours to get the air out if they're dry. (I don't really know how effective massaging oil into one would be, then, but hey.) Anyway it's a piece of cake if you have a vacuum pump. You just set it and let it run all day.

As a couple of examples, my Cadillac vacuum (1938) has a ring of felt around the bearings to hold oil, with oilers that feed those felts. The machine was WELL used and beaten up, and had bone dry bearing felts, so that was a pretty good indicator that the bearings were run dry. Sure enough, they bubbled all day in a vacuum chamber. On the other hand, one of my handheld Cadillacs (~1950s) was in great shape, and looked well cared-for. When I opened it, the oil felts were still quite wet and the shaft still had a very slight slick of oil on it. Someone actually oiled that machine, amazingly.


Kevin - I'm curious what chemical you use to clean a dry bearing, to prepare it to be made wet.

Post# 434810 , Reply# 15   11/11/2020 at 07:07 by Real1shep (Walla Walla, WA)        

if you find the YouTube vid on re-oiling a sintered bearing with your fingers, you'll think it's magic or slight of hand until you try it. Obviously, if you see fresh oil weeping through to the outside, you've re-oiled the bearing. It's like using a bearing packer or using your palm/fingers....both get the job done properly.

I use MEK usually, in a USC to clean the bushing.....outside, because of the fumes.

I've seen a LOT of dry lubed bronze bushings in small electric motors and it's been trending in production to use them for a very long time. Never been a problem in Elux motors up to the Diamond J(haven't done any newer than that). The Cadillac way is to put sealed roller bearings on either end of the shaft. But that's more $$ in production so usually at least one end is a bronze bushing.


Post# 434820 , Reply# 16   11/11/2020 at 12:12 by Real1shep (Walla Walla, WA)        

he explains this better than I can!



Post# 434821 , Reply# 17   11/11/2020 at 12:23 by Real1shep (Walla Walla, WA)        
And this link....

You don't need holes in bronze bushings for oil dilivery if they are sintered, as the oil will pass through and lubricate the shaft. So if there is a 'wick' as such, it only needs to stay wet to deliver oil to the shaft through the sintereed bushing.

However, in really old vacuums you will run into bushings with holes and wicks for oil delivery. But if you size them with newer sintered bushings, you can replace the old bushing design....keep the wick though if at all possible;clean it and re-oil....the wick just needs to be wet, not swimming in oil or you'll create other issues.

Still haven't found that vid with the Norwegian guy re-oiling a bushing with his fingers.



Forum Index:       Other Forums:                      

Comes to the Rescue!

Woops, Time to Check the Bag!!!
Either you need to change your vacuum bag or you forgot to LOG-IN?

Discuss-O-MAT Log-In

New Members
Click Here To Sign Up.

Discuss-o-Mat Forums
Vintage Brochures, Service and Owners Manuals
Fun Vintage Washer Ephemera
See It Wash!
Video Downloads
Audio Downloads
Picture of the Day
Patent of the Day
Photos of our Collections
The Old Aberdeen Farm
Vintage Service Manuals
Vintage washer/dryer/dishwasher to sell?
Technical/service questions?
Looking for Parts?
Website related questions?
Digital Millennium Copyright Act Policy
Our Privacy Policy