B1750 Drive issue

[Derkis]

Hello,

I was out blowing snow with my B1750 this morning when I heard a horrible noise and suddenly had drive issues. I found some pieces on the ground, which is never a good thing. It looks like the HST spring somehow liberated itself, fell into some moving parts, and broke something in the process. Now when driving the tractor, the front left tire slowly spins forward no matter the situation: 4WD, 2WD, forward, reverse, always spinning forward.

I'm pretty new to tractor maintenance. I'm guessing this is a really big problem, but does anyone have any idea what could cause this? Are there any trouble shooting steps I can take to determine exactly which parts died a loud and horrible death?

 

[North Idaho Wolfman]

First what is an HST Spring, you're going to have to post pictures of whatever it is that you have.

And I don't think I understand what you mean by this:

Now when driving the tractor, the front left tire slowly spins forward no matter the situation: 4WD, 2WD, forward, reverse, always spinning forward.

I think a video will really help.
Make a video of it, post it on YouTube and then give us a link to see it.

Sounds like from the top of my head that you have a front axle issue.
Possibly damage to the Bi-speed unit if so equipped.

 

[SDT]

Hello,

I was out blowing snow with my B1750 this morning when I heard a horrible noise and suddenly had drive issues. I found some pieces on the ground, which is never a good thing. It looks like the HST spring somehow liberated itself, fell into some moving parts, and broke something in the process. Now when driving the tractor, the front left tire slowly spins forward no matter the situation: 4WD, 2WD, forward, reverse, always spinning forward.

I'm pretty new to tractor maintenance. I'm guessing this is a really big problem, but does anyone have any idea what could cause this? Are there any trouble shooting steps I can take to determine exactly which parts died a loud and horrible death?

I have a B1750HST with Bi-Speed Turn, and agree with Wolfman. Insufficient information.

FWIW, the spring that returns the HST Pedal to neutral is very close to the front axle driveshaft and vibration causes it toresonate and rub. The vibration/resonance, causes metal fatigue. My spring failed 3 or 4 years ago leaving the HST pedal in forward until I manually pulled it back to neutral. The replacement spring has a short piece of rubber hose inside to dampen vibrations. Does your HST pedal return to neutral as it should?

The good news is that the spring is inexpensive and can be replaced rather easily with a bit of innovation.

Again, need photos or, better yet, videos.

 

[jaxs]

 

[Derkis]

> Does your HST pedal return to neutral as it should?

No. I found a mangled spring with a short piece of rubber hose attached. I also checked where the spring should be and it's definitely not there anymore. I think that it broke free and fell into the front axel drive shaft somehow and caused some damage while getting destroyed. I can post a picture later, but it just looks like a piece of wire all bent up. I'm more concerned with whatever damage it caused in the process.

I can take a video of what's going on with the front wheels and post it tomorrow.

 

[SDT]

> Does your HST pedal return to neutral as it should?

No. I found a mangled spring with a short piece of rubber hose attached. I also checked where the spring should be and it's definitely not there anymore. I think that it broke free and fell into the front axel drive shaft somehow and caused some damage while getting destroyed. I can post a picture later, but it just looks like a piece of wire all bent up. I'm more concerned with whatever damage it caused in the process.

I can take a video of what's going on with the front wheels and post it tomorrow.

Procure and replace the spring first. Buy the proper spring from Kubota.

The spring is quite close to the driveshaft but you can finess it a bit to provide a bit more clearance. You will be able to hear it if it is in contact.

Wear in the mechanism, including the HST pedal dampener allows clearances to decrease. Replacing the spring is easy but replacing the dampener is not.

I also replaced the HST pedal roller and the composite bushing on the HST control shaft before readjusting the neutral position. Mine works like new.

 

[jaxs]

Procure and replace the spring first. Buy the proper spring from Kubota.

The spring is quite close to the driveshaft but you can finess it a bit to provide a bit more clearance. You will be able to hear it if it is in contact.

Wear in the mechanism, including the HST pedal dampener allows clearances to decrease. Replacing the spring is easy but replacing the dampener is not.

I also replaced the HST pedal roller and the composite bushing on the HST control shaft before readjusting the neutral position. Mine works like new.

IMO that falls under pro-active maintenance that could save not only breakdowns like OP's but "click no start" and others. Not to mention make tractor safer.

 

[Derkis]

I wasn't able to grab a video (yet) but I've got some photos. Here are the pieces I was able to find:

I found some more inside the cover. First picture is from above, second is from below (sorry for the poor focus):

I'm assuming from what I can see in the parts diagram that the spring wrapped around that shaft is supposed to attach here:

I jacked up all 4 tires and got no spin on either front tire, and slightly more spin on the back left than the back right. Same behavior in 2WD and 4WD. I'm still working on getting a video of this.

 

[GreensvilleJay]

curious am I... is it spring/hose #030+ 035 in this drawing ? If so maybe #060,070 got loose, #050 slack,then all hell broke loose ?

 

[Dustball]

I jacked up all 4 tires and got no spin on either front tire, and slightly more spin on the back left than the back right. Same behavior in 2WD and 4WD. I'm still working on getting a video of this.

All four tires were in the air at the same time?

It's not unexpected if one tire on one axle spins faster than the other- it's an open differential.

How are you spinning the front tires? By turning the driveshaft by hand?

 

[SDT]

curious am I... is it spring/hose #030+ 035 in this drawing ? If so maybe #060,070 got loose, #050 slack,then all hell broke loose ? View attachment 121512

I replaced 030, 110, and 150 before readjusting neutral via cam 120.

When bushing 110 wears, spring end of arm 100 can move closer to driveshaft due to spring pressure, etc.

OP needs to do what I did. Not difficult.

 

[Derkis]

curious am I... is it spring/hose #030+ 035 in this drawing ?

Yup, looks like it

I replaced 030, 110, and 150 before readjusting neutral via cam 120.

When bushing 110 wears, spring end of arm 100 can move closer to driveshaft due to spring pressure, etc.

OP needs to do what I did. Not difficult.

That sounds like a good plan. I'm still trying to find the best way to gain access to this area. I don't have a lot of experience with either this tractor or maintaining them, so this is all new ground for me.

All four tires were in the air at the same time?

It's not unexpected if one tire on one axle spins faster than the other- it's an open differential.

How are you spinning the front tires? By turning the driveshaft by hand?

I was (attempting) to spin the front tires by putting it in 4WD and "driving" forward while up on blocks. I would expect the front tires to spin by doing this, right?

 

[SDT]

Yup, looks like it


That sounds like a good plan. I'm still trying to find the best way to gain access to this area. I don't have a lot of experience with either this tractor or maintaining them, so this is all new ground for me.



I was (attempting) to spin the front tires by putting it in 4WD and "driving" forward while up on blocks. I would expect the front tires to spin by doing this, right?

Mark the position of cam 120 before removing 140, 120, 110, and 100 to replace bushing 110 and roller 150. After reassembly, return cam 120 to marked position to be close to neutral. IIRC, there is a small plate on the frame that must be removed to gain access to neutral cam and associated parts.

Mark position of adjusting nuts before loosening to gain slack for spring installation. Lower new spring from above with suitable coat hanger wire, etc., before attaching to hole in 100 from below (or lower coat hanger from above to attach to spring after attaching spring to hole in 100). Installation of spring in hole may produce more clearance between spring and driveshaft depending upon which side spring is installed into hole. Cannot remember proper side so may need to experiment. Pull spring up with coat hanger wire to install in hole in 050. Tighten adjusting nuts to approximately marked position.

Readjust neutral by turning 120 ever so slightly back and forth to achieve neutral (no motion) with foot removed from HST pedal. Perform adjustment with oil at or near operating temperature.

Check for clearance between spring and driveshaft.

Should also check for damage to driveshaft U joint due to spring wire wound around driveshaft.

Not difficult and can be done by one person without any special tools.

 

[Derkis]

Well, more bad news. You can kind of see it from the pictures above, but when the spring wrapped around the shaft it sheared several bolts that hold it into the transmission:

It's difficult to access this area, so I have no idea how I'm going to get those bolts out. I see some serious disassembly in my future.