Motor Brushes

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If I can''t find the exact OEM brushes for a motor (vacuum cleaner) at ceahp enough price, what are the disadvantages of substituting a generic which might be undersized? I don't care if it lasts only half or quarter than the original. Original lasted 35 years; so if the new only last 10 years, I would still be happy. Surely, it must be better than stuffing couple of magnetic disks there to force the brushes to make the contact again! That is what I have done right now. I have had few spare brushes from HF tools but the end caps are different and they will not fit. I am planning to go ahead and order cheap different size brushes from ebay and see if I can somehow fit them there. Can I grind the brushes if they are too long or that would create huge big mess with the carbon dust flying all over? Can the brushes have lot of lateral play inside the housing or they need to be snug fit?

I bet bunch of you have lot more experience with brush swaps on motors and I would like to hear from you.
 
Two thoughts:

1) Sure, you can grind down larger brushes. Wear a mask and goggles.

2) Try an electrical specialty shop. Last summer I needed to rebuild an alternator. $200 to get one locally, or $120 shipped and wait. There was NO internet supply for the bearings and brushes. Nada. I went to a local auto electric place and the lady looked at the parts, measured them, eventually came back with the exact parts, bearings and brushes. I had my friend's car back on the road later that day for $26 total instead of $200.
 
Looking around works. No one designing a device invents a size for an outsourced part just for grins. They use something that already exists. All you have to do is start looking. Machines have very few if any wear parts that are magic and come from never-never land.
 
As mentioned above, it's a simple matter to sand brushes down to the proper size. In fact, it's a common thing to do. Just be aware that brushes are quite soft and a grinder will chew through them quickly. Use care and precision when fitting brushes by hand.
 
Ordered bunch of different sizes from ebay and amazon. I found 9.5x6.5 brushes which should fit snugly and hopefully I can figure out something if the length turns out to be not long enough. Worse comes to worst, I will continue to use the cheap magnets or balled up aluminum foil!
 
Well, tried few ebay brushes but the only way I can see it working if I can figure out how to take the copper wire and spring from the old carbon block and put it on the new carbon block. Is that even possible? I hope somebody knows what the heck I am talking about :-(
 
What's the issue? Don't you solder the leads and just put the springs in there when you press the brushes in? Shouldn't be any different than a voltage regulator on an alternator...

Is there some specialty base on the oe brush that holds the spring in a special way?
 
The carbon brush has copper wire and the keeper attached to it. The copper wire "sprouts" from the brush. Spring is compressed between the brush and the keeper.

The incoming electrical connection inside the vacuum cleaner is by a spade which pushes on the keeper.

The problem is new brush has shorter wire/spring and the keeper size does not match with the old one.
 
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