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Re: (ET) Pulling bearings on mower motors - Thank You Dean & Chris !

I completely dismantled an old spare deck today, to prepare to weld cracks, Re-make the inner blade surrounds, and sand blast & paint it all (Imron maybe ?). 

It had only 2 motors on it, both need bearings.

I followed Deans recommendation and bought the bearing puller set.
Then I followed Chris' suggestions (including thread chaser to get max turns of socket head screw into shaft). 

The hubs on both motors did not budge.
So, I wrapped a custom coil for my induction bolt heater around the hub, heated for about 60 seconds, and tried again.
It was still difficult, but I got it to move.  60 more seconds of heating & it came off. I used a large long screwdriver to prevent the puller from twisting as I turned the puller screw with a crescent wrench.  I should have used a socket & long breaker bar for the screw, but I am not sure how I could better hold the bearing puller setup to prevent turning. 

Any suggestions ?

Similar process 2nd motor, except only took 60 seconds heating 1 time.
The bearing puller set worked better than a previous setup I had tried (similar style press plates, but 2 jaw puller instead of the Deans recommended setup): this time the blade end cap came off without cracking !
Following Chris' step 10, I did NOT use socket head screw, - but I SHOULD have (or something similar), because the puller damaged the end of the shaft, and I had to run chaser through again. The 2" bolt was too long for the bearing pull, so for the next motor, I will try a short bolt, or even a thick washer.
This was a non functional spare deck that had been sitting outside for years.  So the blade end bearing was seriously rusted.
I ended up using a chop saw (14" abrasive blade) to cut through outer race & pry it off. (Super careful - a slip would cut the windings or into the shaft)
Then I held the armature with one hand, and pulled saw carefully down, held a position, and moved armature back & forth to shave inner race until it was close to the shaft. 

Nicked the shaft a tiny bit.
A couple taps with a cold chisel split the race, and it slid off easily with channel pliers. 

Armature needed cleanup on wire wheel bench grinder.

for corrosion on end caps I used Dremel tool & 1" wire wheel - worked 
great.
Brushes were seized (corroded aluminum) but gentle taps with hammer & punch moved them, then scraped inside each rectangle brush holder with tiny slotted screwdriver & utility knife.
The brushes now go back in with firm finger push, but still drag too much for proper operation (spring push). 

Again, any suggestions for a better method ?

SADLY, the brush springs had rusted & broken.

Anyone know where I can buy these ?
Bearing note: the small bearing was not very rusty, but did not turn. I put drops of oil at the shield groove & freed it up. The bearing did not feel 'BAD'.  I ran outer race against wire wheel bench grinder (NOISY !). EASY way to tell your bearings are not as good as you hoped ! 

I hope anyone else attempting this has less trouble than I have had.

I really appreciate the suggestions people have posted on this subject.

I welcome any more suggestions (especially brush spring #'s, sources, etc).

John


On 4/21/24 16:28, Christopher Zach via Elec-trak wrote:
Ok, so I went out to the shed and pulled the bearings on an older fat motor armature. Here are some thoughts:
1) The screw to take off the blade hub (hat) needs to be a 2 inch, 7/16 thread socket head screw. ACE hardware stores have 1.5 inch steel and 2 inch stainless. Get the 2 inch one.
2) When screwing it in you should be able to go 10 full turns. Note that although the hole is threaded the blade bolts didn't really go in far, so most of the thread in there is crapped. Might want to clear it with a thread cutter, just don't break the thread cutter off in the hole or that's probably that.
3) I went in 5 turns with my bolt before it got tough to turn on my motor (another spare I had went in 10) which I figured was "good enough". In my case it was.
4) The bearing puller set Dean posted is what I have, it's great, when you hook it up to pull the hub remember not to tighten it so tight it grips the shaft. Use the big puller for all work, there are reasons.
5) Put some grease on the head of the bolt so the puller can turn easier against it. Wheel bearing grease is always nice to have. 

6) Turn, wait, turn a bit more. Slow. It will eventually come.
7) Removing the bottom bearing from the bottom of the motor housing case is a pain. It should not be that tight.
8) When removing the bottom bearing do NOT try to grip the bearing from the inside race. Doing so risks nicking or cutting the armature wires down there especially if the factory bearing was driven too far and popped the circlip
9) Speaking of which make sure the circlip is proper on the motor shaft. Sometimes it's bashed back.
10) Pull the bearing slowly, you don't need the bolt once the blade hub is off.
11) I clean up the shaft with a wire brush on the grinder to get rid of the crud, and put on the new bearing with a tiny bit of grease on the inside and tapping it on with a socket plus wood buffer plus hammer that's just the size of the inner race. Don't pound it too far, just to the point where it touches the circlip. You can go too far and drive the circlip down, then you have to pull it and start over.
12) Top bearing is easy to replace, just needs to be put on flush with the shaft.
13) I put a thin bit of anti-seize on the new hub just so in 50 years someone will try to remove it and go "wow this was simple. Thank you old man from 50 years ago!"
Now I need to find a fat motor top and assemble this with the shattered magnet to see if/how it works. Then pull the new thin motor so I can get the hub off of it, then the armature out, then take a look at what I can do to press the high commutator bars back down....
Never dull. Glad I have a stash of bearings, the old ones are really in pretty sad shape. New ones are so nice and quiet....