Oil Leak on Left Front Rim of L3710 4WD

[TheOldHokie]

6208-4, I'm not sure what -4 means, but I don't think it represents C4 clearance.

KOYO bearing with C4 clearance would be labeled as 6208/C4 or 6208C4.

As I said its a guess but an educated one.

I have purchased hundreds of KOYO bearings. What they choose to etch/emboss on a bearing is up to them and varies according to their whim. I have a 6205 here that has nothing other than C3 on it. A 5206 has 5206RS On both rubber seals but no clearance. Both BOXES have the full catalig number on them. See below.

So what do you figure the 4 signifies and why?

Dan

 

[Mr Haney]

The bearings arrived. It's an interesting design.

They are not sealed against dust. A dust-sealed bearing will have a plate on each side to keep everything out. These bearings have weird shields that cover the balls but appear to let grease in.

It looks like the purpose is to keep big pieces of metal out while letting grease get to the balls. I think it would have been a mistake to buy generic bearings with no shields because metal could have gotten into them. Kubota may have chosen this design because they knew bits of metal sometimes come off gears.

Maybe an ME could provide better information.

 

[TheOldHokie]

The bearings arrived. It's an interesting design.

They are not sealed against dust. A dust-sealed bearing will have a plate on each side to keep everything out. These bearings have weird shields that cover the balls but appear to let grease in.

It looks like the purpose is to keep big pieces of metal out while letting grease get to the balls. I think it would have been a mistake to buy generic bearings with no shields because metal could have gotten into them. Kubota may have chosen this design because they knew bits of metal sometimes come off gears.

Maybe an ME could provide better information.

The OEM bearing is an open bearing - no shields or seals.

Lubrication of open bearings comes externslly from their surroundings.

Sealed and shielded bearings are internally lubricated at ths factory snd do not get luhrication from their surroundings. They are often called permanenuly lubricated bearings

 

[Mr Haney]

As I said, they do have shields.

 

[TheOldHokie]

As I said, they do have shields.

This is the OEM beating pictured on Messicks site. Its an open bearing with no shields or seals.

 

[Mr Haney]

Maybe I'm using the wrong term. I mean the balls are not directly exposed, the way they are in many bearings. As you can see, they are covered up.

 

[TheOldHokie]

Maybe I'm using the wrong term. I mean the balls are not directly exposed, the way they are in many bearings. As you can see, they are covered up.

If you are talking about the picture I posted that is a standard OPEN deep groove radial ball bearing also known as a Conrad type ball bearing.

The races on Conrad style ball bearibgs are ground on an eccentric which when properly positioned creates a "loading slot" that allows the balls to be inserted from the side. The races are then repositioned to eliminate the loading slot, the balls are evenly spaced around the circumference, and on partial complement ball bearings a cage is installed to keep the balls properly spaced when in service.

The cage has nothing to do with sealing or shielding and is what you will get in any generic deep groove ball bearing whether its open, sealed, or shielded.

Dan

 

[Mr Haney]

In that case, never mind.