B1750HST Front Drive Shaft

[SDT]

Lately, I've noticed noise that appears to be coming from the U joint in the front axle driveshaft.

The front drive shaft is enclosed and there is no mention of any required servicing of the U joint in the Owner's Manual.

Upon loosening the plastic joint between the rear driveshaft cover and the front U joint cover, a small amount of oil escaped. The U joint is not visible and it appears that the U joint cannot be serviced without removing the front axle from the tractor. There are no provisions for adding or draining oil from the front U joint cover, though the assembly is sealed with a gasket.

Anyone know if there should be oil inside the U joint/driveshaft cover?

The WSM is not helpful regarding these questions.

Anyone know if the U joint can be serviced without removing the front axle from the tractor.

This tractor is equipped with Bi-Speed Turn.

Thanks in advance.

SDT

 

[William1]

Did you remove the pin from the fixed side of the shaft? Once out, you should be able slide the shaft in enough to the have the sliding side come off the splines.

 

[SDT]

Did you remove the pin from the fixed side of the shaft? Once out, you should be able slide the shaft in enough to the have the sliding side come off the splines.

I saw no pin and the WSM makes no mention of such but I will have another look.

SDT

 

[SDT]

Did you remove the pin from the fixed side of the shaft? Once out, you should be able slide the shaft in enough to the have the sliding side come off the splines.

OK. I found a pin on the rear (HST end) of the driveshaft.

It looks like removing this pin will allow the front drive shaft to be removed, allowing removal of the front U jount cover.

Neither front nor rear U joints have grease fittings, and there is no mention of any required servicing of either in the Owner's Manual.

Did not expect to find oil inside the driveshaft cover so expect that it's time to replace the front shaft seal as well.

SDT

 

[William1]

Id

OK. I found a pin on the rear (HST end) of the driveshaft.

It looks like removing this pin will allow the front drive shaft to be removed, allowing removal of the front U jount cover.

Neither front nor rear U joints have grease fittings, and there is no mention of any required servicing of either in the Owner's Manual.

Did not expect to find oil inside the driveshaft cover so expect that it's time to replace the front shaft seal as well.

SDT

A lot of universals are sealed units.

Is the front axle housing low on oil? I ask because on my little BX, when I do the engien oil filter, some drips on that cover and when it eventually is removed for some reason, I expect to find oil and dirt caked up inside. How much oil did you find? Tablespoon? Cup?

 

[SDT]

Lately, I've noticed noise that appears to be coming from the U joint in the front axle driveshaft.

The front drive shaft is enclosed and there is no mention of any required servicing of the U joint in the Owner's Manual.

Upon loosening the plastic joint between the rear driveshaft cover and the front U joint cover, a small amount of oil escaped. The U joint is not visible and it appears that the U joint cannot be serviced without removing the front axle from the tractor. There are no provisions for adding or draining oil from the front U joint cover, though the assembly is sealed with a gasket.

Anyone know if there should be oil inside the U joint/driveshaft cover?

The WSM is not helpful regarding these questions.

Anyone know if the U joint can be serviced without removing the front axle from the tractor.

This tractor is equipped with Bi-Speed Turn.

Thanks in advance.

SDT

Found it, and it is not the U joint.

While examining the pin at the rear of the front driveshaft I noticed that the spring that returns the HST pedal to neutral rubs on the rear U joint collar and end of the retaining pin when the HST pedal is in certain positions. This is causinig the noise that I have been hearing. Apparently, the bushing on the pivot for the neutral roller is worn.

This spring failed two or three years ago due to vibration fatigue and I replaced it.

Interestingly, Kubota had determined that there was a fatigue issue with the spring as sometime in the model run the spring was changed to a so-called "spring damper," which is the same spring with a short piece of rubber hose inside to damp vibrations. Because the so-called spring damper was $15 and change whereas the original spring (both still available) was $7 and change and the original spring lasted 26 years, I replaced it with the non-damped spring.

Will need to take a closer look at the bushing on the return to neutral roller lever but it is going to be difficult to get to.

Probably 1/4-1/3 cup of oil inside the U joint cover and it had to come from the front axle driveshaft seal (unless intentionally put there upon assembly) because the system is sealed.

Front axle has no level plug so no easy way to check level. I simply pour in the specified amount when changing.

SDT

 

[William1]

Found it, and it is not the U joint.

While examining the pin at the rear of the front driveshaft I noticed that the spring that returns the HST pedal to neutral rubs on the rear U joint collar and end of the retaining pin when the HST pedal is in certain positions. This is causinig the noise that I have been hearing. Apparently, the bushing on the pivot for the neutral roller is worn.

This sprinig failed two or three years ago due to vibration fatigue and I replaced it.

Interestingly, Kubota had determined that there was a fatigue issue with the spring as sometime in the model run the spring was changed to a so-called "spring damper," which is the same spring with a short piece of rubber hose inside to damp vibrations. Because the so-called spring damper was $15 and change whereas the original spring (both still available) was $7 and change and the original spring lasted 26 years, I replaced it with the non-damped spring.

Will need to take a closer look at the bushing on the return to neutral roller lever but it is going to be difficult to get to.

Probably 1/4-1/3 cup of oil inside the U joint cover and it had to come from the front axle driveshaft seal (unless intentionally put there upon assembly) because the system is sealed.

Front axle has no level plug so no easy way to check level. I simply pour in the specified amount when changing.

SDT

I have to LOL at the 'damper'. Wife's recliner chair has foam chunks inside of the springs to prevent (I assume) that 'sproong' sound on retraction.

It is odd that the HST mechanism is so close to the drive line. Worth some time pondering over as to why and how you can widen the gap (on top of resolving worn parts).

Always interesting when try to fix something, the actual issue is not what you thought. It makes pre-planning all the more difficult.