Kubota T1880 Won't Drive

[Russell King]

So I am assuming that the internal threads in the blade spindle are damaged. You have stated that and previously stated that the bolts were both tightened in a clockwise direction even though there should be one CW and one CCW.

There are the ways that I can think of to fix the mower deck:
1) Drill out the damaged thread and install a Timesert or Helicoil thread repair kit.
2) Replace the damaged shaft in the existing spindle.
3) Replace the complete spindle assembly on the mower deck.

All three will require the removal of the spindle from the mower deck. There are probably at least three bolts but probably four that hold the spindle to the deck (I can’t remember what deck you have and it seems there was and still may be confusion on that so I’m not going to look for your part numbers with much confidence, but will post examples from a mower deck that is associated with your garden tractor model.)

Here is the diagram I chose to reference:


As you can see the highlighted items #10 and #100 are the complete assembly and seem to include the blade and the bolt. Then parts #50 and #140 are the shafts that are in the spindles.

The easiest method is to order the complete assembly you need, remove the old and install the new assembly (Option #3). I think that is well within you capability but you may need some help with deck removal and installation and torque on the bolts to the deck and the blade bolt.

The #2 option would probably be about the same cost since you should also replace the seals and bearings while replacing the shaft. But you can remove the spindle and take it to a repair shop (Dealer or independent mower repair shop) and they can repair it and you could replace it. That could save some money. It is at the edges of what I understand your ability to be so I am not sure you want to do the assembly yourself but it is probably not that difficult.

The #1 option would require you to take the assEmily to a dealer or repair shop or a machine shop. The machinist will put the assembly in a drill press and drill the existing hole to center it in the shaft. Then they will use a tap slightly larger than the bolt size to put a thread into the shaft end. Then an insert is threaded into the shaft restoring the threads to the original size and restoring the shaft to the original condition. This is probably the cheapest option but it is outside your ability to do. If it is the left hand thread that is stripped then this is still an option but the machinist MUST know that the threads are not the normal threads (and probably what they look like today).

If it was me I would do #3 but I am not strapped for any funds to do it unless the cost of the assembly is exorbitant! I know you have stated limited funds so it may be out of your range.

You can look up the part numbers and get costs for the different parts at Messicks online.

And I wold try to drag a magnet through the yard to find the old blade before you hit it with your mower blades. Something like this

https://www.amazon.com/Toolwiz-Magnetic-Sweeper-Telescoping-Construction/dp/B0CRNLKK5W/ref=asc_df_B0CRNLKK5W?tag=bingshoppinga-20&linkCode=df0&hvadid=80539436594892&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=74163&hvtargid=pla-4584138920774939&hvocijid=8528275010745240126-B0CRNLKK5W-&hvexpln=0&th=1

 

[Caden]

@Pat_USA This mower is a never ending problem for you.
As Hagrid says, a tap to recut threads is a possibility, but not a for sure thing.

The alternative, if the threads are wiped out, is to replace the spindle shaft that the bolt threads into. That is a larger job.

If you buy a tap, it will be thread pitch M12x1.25.

Yes you will need to buy the bolt and washer.

While it may have been the mechanics fault, a blade coming loose while mowing two different times I'm thinking, has also been hard on the threads when it flys off.


Can you not see where the mower stoped cutting on one half and find the blade?


Final thought here, is to make sure that the washer is installed correctly to maintain tension on the bolt.

and, @Russell King types faster than me again!

 

[Pat_USA]

A bottom/finish tap might get you back in business.

Can you explain some more? I don't understand.

The last mechanic lost the blade, bolt, and washer on the left side. He found the blade but not the washer or bolt. He said he ordered the bolt but didn’t show up for a few weeks, so I ordered the bolt and washer myself. When my order arrived, I installed the blade, new bolt and washer and cut my yard. By the end, I noticed the blade, new bolt, and washer were all gone, and I have no idea where these three pieces ended up in my yard. My guess is that the inside threads are damaged, which caused them to fall off. If it’s not the threads, what else could make all three pieces come off?
I think all the belts are intact.

 

[Caden]

Can you explain some more? I don't understand.

Think of a tap kind of like a bolt, but made out of very hard steel. It is a tool used to thread into holes to cut new threads or to fix threads that have been crossed etc.

A bottom tap is similar to a regular tap. You can't cut brand new threads, but it is best for your situation since it will just be fixing your current threads and go clear to the bottom of the hole.

However, all of that is dependent on how bad it is right now. If the threads are a little messed up it will do the job. If they are completly worn down, then there is not enough metal left for the tap to "cut" into.

 

[Caden]

what else could make all three pieces come off?

One possibility is the bolt was not tight enough.
Another possibility is that that cupped washer was installed upside down, not keeping tension on the bolt.

 

[hagrid]

My assumption is the threads were damaged and didn't let the bolt bottom out resulting in the spring washer not clamping the blade.

That scenario allowed the assembly to dis-mantle itself.

 

[Pat_USA]

@Pat_USA This mower is a never ending problem for you.
As Hagrid says, a tap to recut threads is a possibility, but not a for sure thing.

The alternative, if the threads are wiped out, is to replace the spindle shaft that the bolt threads into. That is a larger job.

If you buy a tap, it will be thread pitch M12x1.25.

Yes you will need to buy the bolt and washer.

While it may have been the mechanics fault, a blade coming loose while mowing two different times I'm thinking, has also been hard on the threads when it flys off.


Can you not see where the mower stoped cutting on one half and find the blade?


Final thought here, is to make sure that the washer is installed correctly to maintain tension on the bolt.

and, @Russell King types faster than me again!

When I reinstalled the blade, I turned it counterclockwise until it was tight. The yard didn’t look as neat as it should, with grass overgrown to knee height and more, but I cut it twice using two settings. I checked under the deck to confirm the blades were gone after finishing the mowing. Even when I trimmed with the trimmer, the grass was also overgrown. I might use a magnet to sweep the backyard if I can’t find the blade, I’ll have to buy another set of blades. I’ll see if someone understands your explanation; otherwise, I’ll contact the local Kubota dealer and possibly remove the deck to have them rethread it. Believe me, this guy never ordered the bolt as he claimed—he just lied. He also needs to come back to fix a few things on my truck, but he didn’t. Overall, his skills are better than most mobile mechanics I’ve hired.

 

[Pat_USA]

One possibility is the bolt was not tight enough.
Another possibility is that that cupped washer was installed upside down, not keeping tension on the bolt.

I turned it counterclockwise and it’s tight. I also installed the washer with the curved side down—it just seemed like common sense to me.

 

[Pat_USA]

Think of a tap kind of like a bolt, but made out of very hard steel. It is a tool used to thread into holes to cut new threads or to fix threads that have been crossed etc.

A bottom tap is similar to a regular tap. You can't cut brand new threads, but it is best for your situation since it will just be fixing your current threads and go clear to the bottom of the hole.

However, all of that is dependent on how bad it is right now. If the threads are a little messed up it will do the job. If they are completly worn down, then there is not enough metal left for the tap to "cut" into.

View attachment 179523

 

[Pat_USA]

I know the tap, so does "a bottom tap" work for both clockwise and counterclockwise threads?

 

[Anil8tor]

I know the tap, so does "a bottom tap" work for both clockwise and counterclockwise threads?

no you'll need to ask for a left handed tap. if it was me i would get the next larger tap, a dill bit for the same and the next larger left handed bolt, drill it, put some light oil on the tap and cut new threads

 

[Russell King]

I know the tap, so does "a bottom tap" work for both clockwise and counterclockwise threads?

A standard tap is tapered towards the working end so it cuts the threads in stages. Because of that it can not cut the threads completely near the bottom of a blind hole. If you need more thread depth in the blind hole you then switch to a bottom tap that will cut threads nearly to the bottom of the hole creating a fully tapped hole.

That is often required to allow the bolt to clamp the blade correctly and not be “tight” by just being jammed in the incomplete threads cut by a standard tap.

 

[Pat_USA]

no you'll need to ask for a left handed tap. if it was me i would get the next larger tap, a dill bit for the same and the next larger left handed bolt, drill it, put some light oil on the tap and cut new threads

The issue is whether there’s a larger bolt with counterclockwise threads, since I need to purchase this special bolt, in the right size for this model, directly from Kubota. I suppose I’ll have to remove the decking and inspect it first, then possibly take it to the Kubota dealer.

 

[Pat_USA]

A standard tap is tapered towards the working end so it cuts the threads in stages. Because of that it can not cut the threads completely near the bottom of a blind hole. If you need more thread depth in the blind hole you then switch to a bottom tap that will cut threads nearly to the bottom of the hole creating a fully tapped hole.

That is often required to allow the bolt to clamp the blade correctly and not be “tight” by just being jammed in the incomplete threads cut by a standard tap.

It’s a bit too complicated for someone with limited experience, but I’ll understand it someday.

 

[Anil8tor]

The issue is whether there’s a larger bolt with counterclockwise threads, since I need to purchase this special bolt, in the right size for this model, directly from Kubota. I suppose I’ll have to remove the decking and inspect it first, then possibly take it to the Kubota dealer.

tap drill and grade 8 bolt, your local hardware.Take the old bolt to show them so they know what your doing. I would not involve Kubota until you think you cant do it. they will want to replace the spindle

 

[Pat_USA]

After removing the decking, I checked the inside threads on the left side, which turn counterclockwise. I noticed the threads at the end of the opening had very little depth left, which is why the bolt and washer couldn’t hold a heavy cutting blade. I think the best solution is to visit a local Kubota dealer to have them rethread it and order a new blade set, washer, and bolt. What do you think is the best option?

 

[Caden]

To be honest, to me, it doesn't look too bad based on the picture.

I think you or someone should be able to fix what you have there.

I am hesitant to advise because I don't want to give you bad advise. I get the feeling that a dealer will opt to replace the spindle or shaft rather than rethread. I would be interested to hear @Russell King 's thoughts here.

Also in regard to your earlier post, it sounds like you had the washer right but I got confused. To be clear, view the following drawing.

 

[Anil8tor]

To be honest, to me, it doesn't look too bad based on the picture.

I think you or someone should be able to fix what you have there.

I am hesitant to advise because I don't want to give you bad advise. I get the feeling that a dealer will opt to replace the spindle or shaft rather than rethread. I would be interested to hear @Russell King 's thoughts here.

Also in regard to your earlier post, it sounds like you had the washer right but I got confused. To be clear, view the following drawing. View attachment 179558

Caden, my thoughts are the same, dealer will just want to replace the spindle instead of tapping this one

 

[Pat_USA]

To be honest, to me, it doesn't look too bad based on the picture.

I think you or someone should be able to fix what you have there.

I am hesitant to advise because I don't want to give you bad advise. I get the feeling that a dealer will opt to replace the spindle or shaft rather than rethread. I would be interested to hear @Russell King 's thoughts here.

Also in regard to your earlier post, it sounds like you had the washer right but I got confused. To be clear, view the following drawing. View attachment 179558

I installed it as shown in your picture. The inside threads don’t look bad in the photos, but the bottom 3/8" is almost smooth. This has happened twice, so the threads are definitely the issue.

 

[Pat_USA]

Caden, my thoughts are the same, dealer will just want to replace the spindle instead of tapping this one

What is the shaft? If the dealer won’t rethread it, I won’t do it. I’ll follow both of your advice. Please explain clearly what needs to be done so I can follow or have someone help me do it correctly. Don’t worry about your advice; I know you have good intentions, and I have common sense to judge what to do since it’s hard to tell from photos.