Help me Make my GCFI Stop Tripping

Cadillac said:
Without any pictures you not gonna get any definite answers. Having a double bearing in the front sounds like you have angular contact bearings in the front ,the rear bearing is gonna be a slip fit for expansion so the spindle doesn't bind up. I would doubt there is cosmoline in the spindle housing dried up grease or oil yes cosmoline no. The front bearing set is there a locknut holding the two bearings on the spindle? When you get some time take some detailed pictures and post it'll be the best way to get some accurate advice.
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I wasn't looking for answers. Just reporting on the situation.

I don't believe there is cosmoline in the bearings. I think the grease turned into something exactly like cosmoline because of the heat from the bad bearings. It's almost as if someone melted a brown crayon in there.

Someone suggested cleaning the old bearings out and re-greasing them, but I don't think the grease would have been corrupted had the bearings been sound. I don't know, though. They appear to be sealed, so I would have to pry the seals off and put them back on. They're supposed to be cheap, so I see no reason to struggle with the old ones.

Why would there be grease on the outside of sealed bearings? I haven't seen that before. Wondering if it migrated out from inside the bearings.

I'm trying to find out what kind of bearings I have. I'm contacting the manufacturer. We'll see how that works out. If I have any trouble with the removal or installation, I'll be back.

I'm trying to find a set of sockets for castellated round nuts. I know they exist, because the nuts exist. I'm finding all kinds of names. "Spanner sockets." "Spindle sockets." "Spindle locknut sockets." Making things more complicated, most are made for automotive use, so it's not like you can look for a set from 1/2" to 1-1/2" with a 1/2" drive. You have to look for Honda, Chevy, or whatever. Also, they're extremely expensive, which makes no sense, because they're very simple to make. I would love to have a set, but it looks like it's easier to make them on demand than to find them ready to buy.

For anyone else who makes a tool for these nuts, don't make the mistake I made. Do not make an 8-pin tool. You only need 4 pins. It's much easier to make on the mill.

A company called SKF makes a bunch of tools for this type of nut.

 
Looks like old grease to me. I'd think that if the bearings overheated the grease would have 'melted' out of them.
 
So those are angular contact bearing on the wheel side. Those are not seals on the bearing that is the cage for the bearing angular contact have a different kind of cage to your typical sealed bearing. Keep track of the orientation of those bearings it matters. When you tighten the nut on the wheel side where that open thread is it will preload the AC bearings. The only way to check condition of bearings is cleaned out completely and look at race and balls for fretting. Like said before the rear bearing should be a slip fit and there should be a wavy washer or bellevue washer to preload the rear bearing for expansion.
 
When you identify your bearings, I recommend not bringing your coffee to the computer with you to look up the prices. That's the spindle of a Gorton machine, possibly with a double-row cartridge on it. If original, the bearings probably have a word like SKF or Timken or something similarly excellent etched on them. I've been okay with sourcing new old stock bearings on eBay, but non-chinesium off-the-shelf bearings of the appropriate precision rating can be exorbitant in cost. Only reason I am pointing that out is to make the idea of solvent washing and re-packing your existing bearings a little more palatable. There is nothing wrong with re-packing a bearing unless it is brinelled or rusted from abuse or otherwise worn in a verifiable way. High end bearings can go for an incredibly long time compared to the automotive grade stuff we are used to tearing into, so replacement may not be necessary in the broader scheme.
 
As noted previously, the guy who is advising me after his own rebuild says these are common bearings. I am hoping Gorton will get back to me so I will know exactly what to get.
 
They sent me some numbers. I am Googling this stuff to find out how bad the news is. Regardless, I do plan to see about fixing the old bearings.
 
Okay. The news from Gorton is not as wonderful as I had hoped, but it's not tragic. I see a range beginning at about $125 for two bearings. I was hoping for more like $20 for a pair, but $125 will not ruin me.

This is the number for the forward bearings. The other one seems to be fine, so I don't see any reason to replace it.

If anyone has advice about opening these old ones up and putting them back together, I would appreciate it. In the meantime, I will be Googling.
 
That's not too costly, glad to hear it. Some bearings cost their weight in gold (well, at least the weight of the balls).

Depends on the type of bearing, but most cartridge bearings stay together because they are swaged at the factory. I use a fine dental pick and carefully pry the seals off, then wash in stoddard solvent to remove all the old grease. Dry them with a rag (or compressed air if you dare) and inspect them carefully. Look for axial play, radial play, and rotate them between your fingers to feel for bumps or brinelling. If they have more than a very small amount of play (this is subjective, but common sense should apply) or if there are any tight/rough/bumpy spots, then they need to be replaced. If they run smooth, congratulations! Repack them with a grease selected for temperature and bearing speed, pop the seals back in, and enjoy grinding tool bits with your refreshed grinder. Did I skip the part about preloading the spindle? Yeah, I skipped that part... You'll need to glean any information you can about bearing/spindle preload from the manual or from the manufacturer's support line. Every machine is different, and preload is a crucial tolerance based on loads and heat. Considering it's a simple grinder, it may not be a huge deal, but the engineers planned for it by building adjustability into the spindle assembly, and probably wrote down the spec somewhere. There are tricks to measuring preload, but it all depends on the form in which the spec is given.
 
I found some useful information for anyone else with these bearings. The grease you want is Mobil 28. Amazon has it. People will tell you to get nutty Euro grease, but Mobil 28 is fine. It's also supposedly the ultimate gun grease, and you can buy it in small syringes for gunsmithing. Should make filling the bearings easier.

Amazon sells the grease for $22 (big tube), and you can get 8 syringes for $9. I thought that was smarter than buying one syringe for $6. I may want to grease other stuff.

 
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