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

 

[JWR]

I always thought the bi-speed turn models were complexity trouble going somewhere to happen but apparently they were well made. Is there not a grease fitting in the U-joint or you just can't reach it to see? Hours on it ? My guess is, if you are hearing noise from it, then it is too late for lubrication anyway.

 

[SDT]

I always thought the bi-speed turn models were complexity trouble going somewhere to happen but apparently they were well made. Is there not a grease fitting in the U-joint or you just can't reach it to see? Hours on it ? My guess is, if you are hearing noise from it, then it is too late for lubrication anyway.

Completely enclosed without grease fittings.

625 hours.

Never a FEL.

SDT

 

[rScotty]

Wasn't there a long thread earlier this year where the guy repaired this very problem? I thini it was in the U-joint or spline of the front driveshaft.
I remember that access was a problem and his solution was innovative and worked.

 

[SDT]

Wasn't there a long thread earlier this year where the guy repaired this very problem? I thini it was in the U-joint or spline of the front driveshaft.
I remember that access was a problem and his solution was innovative and worked.

I do not recall any such thread but I believe that have determined how to remove the front driveshaft without removing the front axle from the tractor with the help of a copy of the parts break-down from the illustrated parts manual.

The rear (HST end) end of the driveshaft is splined and pinned to the rear U joint yoke. It appears that that the pin can be removed allowing the front driveshaft to be slid rearward on the splines far enough to disengage it from the splines at the front. This will allow removal of the front U joint cover allowing access to the U joint.

It appears that it is time to replace the front oil seal while things are apart as I found oil inside of the drive shaft cover.

May work on it again this weekend.

SDT

 

[rScotty]

That sounds good. I agree that's roughly how most driveshafts that live inside of covers are accessed.
It does require that the splines be long enough to slide the front driveshaft back far enough to free one end.
Now my memory is almost working....I remember there was something about that from that previous repair as well. Is your front driveshaft centered or angled or offset?
I'll do some digging tonight just in case there is some more into out there.
rScotty

 

[SDT]

That sounds good. I agree that's roughly how most driveshafts that live inside of covers are accessed.
It does require that the splines be long enough to slide the front driveshaft back far enough to free one end.
Now my memory is almost working....I remember there was something about that from that previous repair as well. Is your front driveshaft centered or angled or offset?
I'll do some digging tonight just in case there is some more into out there.
rScotty

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