RCK72R-F36 Deck spindle

[JohnR68]

This is the center spindle arrangement on the RCK72R-F36(AU) deck. Can anyone tell me if there is supposed to be an interference fit between the shaft (240) and the bearing (030) or if the bearing should be pressed into the housing? When I disassembled it nothing seemed like it has been pressed together, the bearing taps out of the housing and off the shaft with minimal effort. I don't see any significant sign of wear or slop in the housing or on the shaft and the bearing was still in serviceable condition. If this is the correct design, with a loose fit onto the shaft and into the housing, can someone help me understand what prevents the outer race of the bearing spinning in the housing or the shaft creeping in the inner bearing race? Does the boss (110) apply some preload to the bearing when the blade assembly is tightened perhaps?

 

[whitetiger]

It should be a slip-fit on the shaft and an interference fit into the housing.
There should be no pre-load on the bearing.

 

[GeoHorn]

I don’t have that exact model…but a similar one…and the bearing is all slip-fit. The circlip-and-spacer (items 40 and 35) are what prevent the outer race from rotaing within the housing. (It’s not as critical as one might think.)

 

[GeoHorn]

ONe more thing: That bearing likely has a number embossed on the seals….which can be searched and found available online. When my bearings became worn I was surprised to find I could buy a box of a dozen with shipping for less than OEM wanted for one.
When the box arrived…they were identical in every way and have been very durable.

 

[JohnR68]

ONe more thing: That bearing likely has a number embossed on the seals….which can be searched and found available online. When my bearings became worn I was surprised to find I could buy a box of a dozen with shipping for less than OEM wanted for one.
When the box arrived…they were identical in every way and have been very durable.

Thanks Geohorn
Yes I have bought bearings and seals from a local bearing supplier for about that, 1/3 or perhaps even less, than the cost of buying them from the Kubota dealer. The seals were the same NOK brand and part numbers that Kubota use and the bearings were made in Japan jtekt/koyo. The only part he didn't have was the lower grease seal (060) it had an NOK part number on it, but he said he'd called his NOK rep here in Australia and they couldn't identify it, so i got those from Kubota.

 

[whitetiger]

The outer race of the bearing should not be loose in the spindle housing. It is to be a slight interference fit.
If you can install it by hand, it is too loose.

 

[JohnR68]

The outer race of the bearing should not be loose in the spindle housing. It is to be a slight interference fit.
If you can install it by hand, it is too loose.

Yes that is what i intuitively thought it would be like. However this one isn't that way, the old bearing dropped straight out with a couple of light taps on the race with a punch, no hammer just the weight of the punch, and the new one slides in easily by hand. There is no visible sign of wear on the housing. The workshop manual doesn't provide much help it just says to 'remove' the oil seal, snap ring, shim and bearing and to replace the seals and don't forget to reinstall the shim when it goes back together. Do you know if there is any specification for the diameter of the housing available anywhere, that way i can measure it and see if its in spec or not. Or if anyone has one laying around and could measure the internal diameter of the housing I'd be interested to see how it compares with mine.

 

[GeoHorn]

Thanks Geohorn
Yes I have bought bearings and seals from a local bearing supplier for about that, 1/3 or perhaps even less, than the cost of buying them from the Kubota dealer. The seals were the same NOK brand and part numbers that Kubota use and the bearings were made in Japan jtekt/koyo. The only part he didn't have was the lower grease seal (060) it had an NOK part number on it, but he said he'd called his NOK rep here in Australia and they couldn't identify it, so i got those from Kubota.

I’ve noticed that SOME sources suggest Removing or drillng a hole in one of the bearings roller-covers to allow grease to enter the bearing from the zerk. I’ve never done that but it’s maybe a good idea.

 

[Russell King]

You can put some type of bearing retention goop from loktite or similar compound on the outer race. Don’t use something that is permanent though, it should not lock it in there until eternity.

 

[GreensvilleJay]

curious. is there not a 2nd bearing above the spacer (#020) ?
All spindles I've worked on had TWO bearings. Some have a grease zerk on the housing to get grease in. With those , I pop off the 'dust cap' off the bearings, on the 'inside' side.

 

[TheOldHokie]

Yes that is what i intuitively thought it would be like. However this one isn't that way, the old bearing dropped straight out with a couple of light taps on the race with a punch, no hammer just the weight of the punch, and the new one slides in easily by hand. There is no visible sign of wear on the housing. The workshop manual doesn't provide much help it just says to 'remove' the oil seal, snap ring, shim and bearing and to replace the seals and don't forget to reinstall the shim when it goes back together. Do you know if there is any specification for the diameter of the housing available anywhere, that way i can measure it and see if its in spec or not. Or if anyone has one laying around and could measure the internal diameter of the housing I'd be interested to see how it compares with mine.

Just put a small dap of this on the outer race when you assemble it. Dont go crazy if you want to get it out agsin.

Dan

 

[JohnR68]

curious. is there not a 2nd bearing above the spacer (#020) ?
All spindles I've worked on had TWO bearings. Some have a grease zerk on the housing to get grease in. With those , I pop off the 'dust cap' off the bearings, on the 'inside' side.

No, In the center spindle there is only one bearing, the top of the spindle is supported by the bearing in the gearbox, which isn't shown in the diagram. The two outer spindles both have two bearings however.

 

[JohnR68]

I’ve noticed that SOME sources suggest Removing or drillng a hole in one of the bearings roller-covers to allow grease to enter the bearing from the zerk. I’ve never done that but it’s maybe a good idea.

I'd been thinking about this as well, whether to remove the bearing seal on one side or not. It's a subject which seems to arouse a lot of opinion on the internet and I'm not really persuaded one way or the other by the arguments I'd read. The old bearings were unsealed but the new ones have rubber seals. I'd decided to leave both the seals on, I figure if I'm going to take one off I may as well just get unsealed bearings. I think it perhaps depends on how diligent you think you might be with the grease gun. If your maintenance is slack the sealed bearing might be more forgiving, but if you take good care of your equipment i don't see that it would offer much of an advantage.

The question that then comes is if you leave the seal on do you then continue to grease the sealed bearing? I think I will, if my experience of trying to keep, grease, oil, water, any other fluid, in or out of somewhere is anything to go by, some of it always seems to find a way through now matter what you do.

 

[GreensvilleJay]

No, In the center spindle there is only one bearing, the top of the spindle is supported by the bearing in the gearbox, which isn't shown in the diagram. The two outer spindles both have two bearings however.

thanks for the info.