Diagnosing 4WD problems YM240D

[woolyAcres]

A bit of elbow grease is all that was needed to get the top spindle-bear-bottom spindle assembly down out of the housing. In my opinion the parts all look serviceable if not pretty decent. There's a bit of wear on the top spindle gear but I don't think it's enough to warrant replacing it on a ~40 year old tractor so unless. However I'm open to suggestions. Here are a few photos of the parts all removed. I've got new bearings on order, new dust sea, new needle bearings, and that's about it. I think I should have this back together as soon as the parts arrive. Hopefully no other trouble.

Thanks to everyone (especially winston1) for the help. I hope the next person that has this trouble will find this thread and find it useful. I'll post some more photos when I get it things re-assembled.

Regard and many thanks

 

[California]

I guess I haven't been studying this thread as intensively as I thought. So in summary a damaged ball bearing froze up and made a wheel impossible to turn?

I expected only a broken gear could jam the front axle, while a bad bearing would indicate failure by getting increasingly noisy and sloppy.

What's missing in my understanding?

 

[woolyAcres]

I guess I haven't been studying this thread as intensively as I thought. So in summary a damaged ball bearing froze up and made a wheel impossible to turn?

I expected only a broken gear could jam the front axle, while a bad bearing would indicate failure by getting increasingly noisy and sloppy.

What's missing in my understanding?

Hi California-

No you didn't miss the diagnosis. I was looking for/expecting a smoking gun- broken gear or piece of metal jamming things. That's not what I found.

My process went something like this:

• Removed the wheel - things still won't turn
• Remove the knuckle - knuckle portion turns freely but the rest of what's connected to tractor won't
• I pulled the center drive shaft that bring power into the front differential back from the center differential; passenger side turns freely, what's still attached to the drivers side does not. conclude problem is on drivers side somewhere between the front diff and the bottom spindle gear
• basically remove everything from the bottom spindle gear back to the differential and separate.
• when this is finally down to just the bottom spindle gear-bearing-top spindle gear, this is the only section that won't turn. Finally bash that out and separate into what's the the last photo. Bearing does turn but it's pretty sticky; however it would not turn- no way, no how- when it was in the front axle top cap.

The gears don't look perfect but they do look alright. When the problem first arose I stopped immediately not wanting to break anything. It's possible if I had just kept going it might have freed up. I've got to believe this problem is from overloading the bucket and putting too much pressure on that bearing. My best guess is that the pressure got that bearing to shift in its housing such that it was cockeyed and that caused it to bind up.

Although I'll be disappointed, I won't be surprised if getting it back together there's still a hitch somewhere. But for now I'm taking comfort in that seized bearing and the fact that everything else seems to be okay. At least now I know how to get this all apart.

 

[California]

Thanks. I learned a lot from your thread.

 

[woolyAcres]

Thanks. I learned a lot from your thread.

Glad to hear it. That makes two of us

I hope it's useful to others too. I feel like I got far more than I gave on this one. I'm always grateful to the generous folks on TBN who use their own time to answer questions from a stranger. I've been on the receiving end of a lot of that on here. I hope this thread will help the next guy.

 

[woolyAcres]

Here's a quick update.

I got my parts from Hoye and started re-assembling things. Interestingly, when I got the top and bottom spindle gears sandwiched around the new bearing and got that bearing back into the 'housing' things don't feel smooth. To explain further, the spindle gears and bearing roll smoothly (before inserting them into the housing where they mesh with the drive axle). And the drive axle turns freely and smoothly in the housing with nothing else installed. But when I put the spindle gears in and mesh them up with the drive axle gear things aren't smooth. It turns, there's no grinding or binding, but it's still not buttery smooth the way the two things turn when not meshed. There is no oil in the system yet. A visual inspection of all the gears didn't reveal any missing teeth, chips, etc. So I'm wondering how important it is that the same teeth be lined up now that were lined up before I disassembled?

At this point I don't think that's possible. I didn't make any note of how the teeth meshed, nor do I know how I could have. Things aren't visible. My gut says, although not as smooth as I was hoping/expecting, this tractor is nearly 40 years old and this is certainly better than what I disassembled, but before putting it all back together I though I'd ask for some input. I suppose part of the roughness I feel here could be what caused the binding up in the first place, or is it expected that the two gears will need some time to 'get to know one another'?

Thanks,

 

[normde2001]

Sounds like gears are meshing too deeply. Never been in there but I know there are shims to determine how deeply they mesh, to give proper backlash. The service manual should explain how to do it.

 

[winston1]

Do you have any backlash? A small amount is necessary to keep bearings out of binding.

 

[Neat 1500]

I'd imagine it would need some shimming to get them to mesh correctly. Leaving them as is will either destroy the bearings or break off the case hardening of the gears and they will be rendered useless.

 

[woolyAcres]

Hi guys, thanks for the input. I'm glad i asked. I do have some shims and my manual does discuss how to adjust for backlash. Am i wrong to think that the shims i took out are appropriate and sufficient?

 

[normde2001]

It's kind of apparent that your problem was caused by improper shimming.

 

[winston1]

Need to assure you have backlash.

 

[clemsonfor]

the shims you took out are fine but there may be more or less needed due to maybe differences in bearing , If you changed that, and or just the wear and tear on the gears in the last 30+ years.

 

[woolyAcres]

It's kind of apparent that your problem was caused by improper shimming.

@normde2001- The bearings I took out are clearly Japanese. Making me think that they were original. I've got no reason to think otherwise. Are you suggesting it could have been improperly shimmed from the factory? I really don't know, but I have to confess to overloading this machine. You might remember the enormous bucket on this tractor. My un-educated guess is that I caused some damage by overloading the FEL and jamming something by driving over a bump with a too full bucket. This didn't actually happen when I had a load in the bucket, but I have no doubt I could have caused something like this just prior to it actually locking up...

 

[normde2001]

Regardless of how it was shimmed before, you need to do it correctly on re-assembly according to the Yanmar manual, or other specs. Anyone could have been into it before.

 

[woolyAcres]

Well, it's back together, following the manual I have. Thanks to everyone for the input and support. Some of the trouble, or non-smooth, issues I was having were because I didn't have the two sets of needle bearings installed when I was checking things. I didn't realize how much of a difference they would make but the spindle shaft must not have been running true down the center of the top and bottom gear. Once I installed those, things roll very nice. There is backlash but my manual didn't discuss how to test/measure it for the spindle gears, only for the front differential so I did what I could there. I guess time will tell if my repair is sound but there's no grinding, whining, or other noises, only smooth rolling (when I tested it with the front wheels off the ground). I've put a few hours on it today and things seem fine both in 2WD and 4WD. No heavy loads in the bucket yet but that's on its way, though I'm going to work hard to keep the loads down from what I had been putting in the front. The bucket is simply too large and too easy to overfill.

I'm sure if it breaks down again you'll hear me moan about it. Again, thanks for all the help.

 

[winston1]

Glad your up and going. I feel like you got a good scald on it, probably last forever. :thumbsup:

 

[clemsonfor]

Sounds like it's a erect repair, should last forever.


So what was the final list of replacement parts again?

 

[woolyAcres]

@clemsonfor- Total bill is about $75 (mostly parts and shipping from Hoye). I ended up replacing (referring to the Hoye parts page), 28 (dust cap) , 59 (bearing), 43 (bearing), 58 (bearing), 47 (needle bearing), and an o-ring. I had to use some gasket maker ($6 from auto parts place) because Hoye didn't have the gasket that fit between the front shaft housing and the front differential.

Not all the bearings were bad (the needle bearings seemed okay, as was 43) but I figured updating them all would be wise.

 

[clemsonfor]

@clemsonfor- Total bill is about $75 (mostly parts and shipping from Hoye). I ended up replacing (referring to the Hoye parts page), 28 (dust cap) , 59 (bearing), 43 (bearing), 58 (bearing), 47 (needle bearing), and an o-ring. I had to use some gasket maker ($6 from auto parts place) because Hoye didn't have the gasket that fit between the front shaft housing and the front differential.

Not all the bearings were bad (the needle bearings seemed okay, as was 43) but I figured updating them all would be wise.

Yep that makes the most sense. You went to all this effort to tear it down there is no reason not to replace a $10 or $20 bearing while you have it all apart. I would have done the same.