AP-100 motor bearing , how to replace?

[quebecois]

I've disassembled a few AP-100 motors during the two past weeks and I noticed that the bearing seems to be impossible to remove from the shaft with hand tools and/or reasonable strength. This bearing is pretty different from the AP-200 motor sealed bearing, easy to remove for change.


For that reason, I decided just to pack the bearing with lots of new bearing grease, but sometimes it is not enough to take that grinding noise away when the motor slows down.


Is there a way or a tool that I'm not aware of that I could use to change these old worn out bearings? Are these greasable bearings still available ?

 

[compactc9guy]

Should be the same motor as Ap 200 unless some one changed it.

 

[quebecois]

Well, this is not what I experienced, the attached picture shows the type of bearing I found in the AP-200s, the type that is easy to remove simply by tapping it out with a ratchet socket.


The type that gives me trouble was probably machine pressed or sort of.

 

[madman]

https://www.ebay.com/itm/4pc-3-Jaw-...earing-Steering-Wheel-Pulley-NEW/172969029871

https://www.ebay.com/itm/Black-Arma...r-Extractor-Installation-Remover/173701164716

If a bearing needs to be pressed off/on, there are certain rules, but the general 'how' of it is totally up to you, and depends on the situation. One tool might work on one armature, and not on another.

Also, these are only removal tools, you'll need something else to install them. Either an actual hydraulic press (small ones can be had for under $100 usd), or a sturdy steel pipe with the inside diameter about the same as the armature shaft (you might be able to get away with a deep socket), and a hammer or a big bench vise.

The most important rule of pressing ball bearings is not to exert the pressing/pulling force on the balls. For example, if you're pressing a bearing's inner race onto the armature shaft, you press from the inner race. If you press from the outer race, it'll press the outer race against the balls, and the balls will press the inner race. This might damage the races, but of course it depends on how much force is applied.

Because of this, it's generally very hard to remove a bearing from an armature by gripping the inner race, so you typically pull against the outer race, and then you consider the bearing destroyed (which it probably was anyway if you were replacing it).

 

[collector2]

For the Ap100 and earlier motors you need a bearing puller to remove the bearing from the shaft and a setter to put the new bearing in place.

 

[texaskirbyguy]

Some pictures would help us to come up with some solutions for you. I am not familiar with those machines, but mechanical engineering works for any of them!
I had made a bearing puller for Kirbys, which worked very well over 5 models across the generations. Installed them with sockets and a hammer, which might sound barbaric. But if you support things well and hit the right places, it is perfectly safe.

 

[texaskirbyguy]

Forgot to add a link to some of my Kirby service techniques for disassembly and assembly, including motor bearings. There are lots of pictures, too, which might help you get some ideas.
https://www.vacuumland.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?34091_7

 

[vaclab]

I Repack Bearings Regularly And...

"Re-seating" them can be as simple as using a socket that matches the outer diameter of the bearing. Getting rusted bearings off might require an inexpensive bearing puller. I paid $7 for mine a few months ago.

Check out this video around the 7 minute mark to see a repacked bearing installation on a Kirby D80.

 

[madman]

That is NOT how you install a bearing - in that video, timestamp 7:27. He's hammering the OUTER race!

Eeenope.

I mean, it might work out just fine, but it's wrong. It's taking a risk for no reason. Makes me cringe. Please read my previous post explaining how to do it properly.

 

[quebecois]

Here are two pictures of where I'm stuck in the process. I don't even know how to remove the last part of the casing the bearing is fitted in. I don't want to break anything (except the old bearing itself) just because I don't know what to do.

 

[vaclab]

MadMan, You Are 100% Wrong

And I have all the tests to prove it! Namely, before and after motor RPM (loaded and unloaded), motor current draw and of course nozzle CFM.

It's plain Physics dude. Think about it.

If I can remove a bearing with a bearing puller placing all the force on ONLY the outer race (actually just the sides), why wouldn't I be able to use a socket that PERFECTLY distributes the re-installation hammering force on the outer race?

The fact that it made you cringe is unimportant. Did you see how gently I re-installed it? How many times did the hammer strike the socket to move new bearing a very short distance? Work through the calculations and you'll see it's a very safe and gentle process.

This method (when reasonably performed) is completely acceptable and widely used on many YouTube videos.

Bill

 

[texaskirbyguy]

Quebecois,
By the looks of you picture, the motor shaft needs to be driven out of that bearing.
First make sure there is not a snap ring hidden under grease and dirt.
Next, take a small length of 2.5"-3" diameter plastic pipe (or similar) and stuff a rag in one end. Insert the motor armature into the other side and place it on a hard surface. Hold a block of wood over the motor shaft to protect the end and tap it out with a hammer. The armature should fall on the rag stuffed inside.
You might want to use some penetrating oil at the shaft and bearing first. The armature should come out after a few taps. Do not hit too hard. If stuck, let the penetrating oil sit longer and try again.
Once the shaft is out, the bearing can be tapped out from the other side with a socket like I did in the link I posted above. Hope this helps!

Bill,
I have to side with Madman here. In the example video, hammering on the outer race transfers the hammer blows from the outer race, through the balls, then to the inner race. This causes micro-divots in the races and tiny dents in the balls. This may cause some sloppiness or noise in the bearing, depending on the quality of the bearing materials and how hard the blows were. I understand your may have gone on with light taps, but some bearings on some machines fit tighter and will require harder hits - I have done some. Therefore in general practice, it is correct to hit the race that is against metal. In the video, all it took was a much smaller socket to go around the inner race.
Unfortunately, tests of current, RPM, or CFM will not uncover bearing damage done from improper installation, unless it is extreme. Before and after tests with a dial gauge might uncover some slop, but graininess, probably not. Noise may develop earlier as well, after the lube starts to dry out.

 

[quebecois]

Thanks Rob, I stacked three shipping tape rolls, put the casing on it and a few light taps were enough to remove the bearing and shaft from the plate.

Now I am at the point I have to use a bearing puller to remove the bearing from the shaft, or is there another way to do it?

 

[madman]

Quebecois - A bearing puller would be ideal, but if you have a couple of angle irons, you can put two next to each other, across two pieces of wood, and put the bearing between the irons, so the armature is hanging in air, suspended by the angle irons under the bearing. Now the tricky part. You want to hammer the shaft straight down, without damaging the threaded end of the shaft. Ideally, you'd use a center punch with a flat end to strike it. It may not even take enough force to start damaging the threads. I'm assuming there was a nut holding the fan blade on? Screw the nut onto the shaft so the top of the nut is exactly flush with the end of the shaft. This is a crude method of protecting the threaded end of the shaft, but it should work fine in this case.

---

Bill - You know, calling me wrong and citing youtube videos (of all things) as evidence of the right way of doing something is really weak evidence. I'm a certified automotive mechanic who does mechanical repairs for a living. I have personally made the mistake of pressing on wheel bearings the wrong way, and though they may look fine and feel fine in your hand afterwards, once installed on the car and driven at some speed, you'll hear a loud bearing noise. Because the races have dents in them from the balls being pressed against the races.

Granted, we're talking about bearings and pressing force on a much smaller scale here, but the same principles apply. You cite plain physics, yet you're not understanding my explanation of the basic physics behind it. Bearing balls are EXTREMELY hard metal. The races are hard, but not AS hard. What happens when you hammer a hard piece of metal against a soft piece of metal? The soft metal gets deformed. Plain physics, as you say. In this case, might not be much, maybe not even a thousandth of an inch, but because of the way ball bearings work, the surfaces involved need to be perfectly smooth. What you're doing, if it doesn't have any immediate effect, is still lessening the life of the bearing... for no reason.

Anyhow, I'm sorry if I offended you.

 

[quebecois]

Madman, well it sounds like a good idea, I may have a couple of these angled irons in my scrap baskets.

 

[quebecois]

I measured the outer diameter of the bearing while it's still on the shaft and it is 26 mm, the shaft itself is 9 mm, so this is obviously not a #608 bearing like the one pictured on my previous post #405122, because its outer diameter is 22mm and it fits an 8mm shaft.

So do you guys have an idea which model of bearing it could be?

 

[texaskirbyguy]

Quebecois,
Check out this picture of my homemade bearing puller to get an idea on how to make one. Mine survived 5 uses, one a very tight one.

 

[quebecois]

Rob, your design is very simple and effective. I don't have easy access to aluminium as thick as your bottom plate, but I suppose I could use a thick piece of very dense hardwood.

By the way, I found a place specialized in bearings not far from my place, mine is a #629 (at first I didn't notice it was stamped on the side of the outer race), I asked the guy to order me 5 of them, he said around 5$ each.

 

[vaclab]

MadMan

After reading your comment, I simply cannot let your false claims and faulty reasoning stand.

Since you probably have never taken a college level "statics and strengths of materials" class or something similar, you seriously have no idea what you are talking about. For good measure, take a Calculus class as well in order to properly digest distributive loads, graphs and charts.

What you completely missed which floors me is that you fundamentally do not understand at what point metals begin to deform and maintain that deformity (forces/loads/vectors).

Think about this my mechanic friend: That bearing I repacked and re-installed was 29 years old. It spins near 10K RPM (roughly), withstands 100's of degrees in addition to centrifugal forces and other forces. It is NOT a wimpy bearing.

I probably struck it with a properly distributed total force of 2 lbs. And the other end of the shaft was hitting the soft wood of a 2x4. Guess what? No dents (deviations) in the 2x4 at all. None.

The process of removing the bearing with a imperfectly distributed force (bearing puller) will do MUCH MORE damage than I would ever come close to doing during the re-installation process. Because you don't understand how the forces are being distributed on the outer race, you don't understand that the potential for bearing damage is dramatically LESS during installation than removal.

Feel free to believe whatever you like considering you have zero measurements or evidence and I will continue to fully recommend my procedure with great success over many years.

Bill