Yanmar 186D broken shaft

[ajaukema]

Hello,

Our YM186D has some issues, the most important: the shaft between the clutch and the gearbox is broken.
It has happened before, a mechanic has welded it previous time, now it is broken again.

Im really surprised how in the world its possible to break such shaft.
Does anyone have an idea for what reason this can happen?

Ordering new parts I can fix this, but just want to be shure it won't happen again, any ideas?

The other thing; a lot of copper coloured shred inside the housing, any suggestions what causes this mess?


Regards,
AJ

 

[HoyeTractor]

I don't think I have ever seen one break in the middle like that either. Usually the splines just get wore out. The brass looks like either your pilot bushing or the bushings inside your throw out bearing carrier but that is a lot of shavings! Maybe combined with shavings from when the shaft broke? That shaft spins at engine speed (relatively fast) so if it was not welded perfectly straight it could have caused the bushings to wear out quickly. Is the circled shaft (powershift pump shaft) in that last picture broken also? Hard to tell in that picture.

Edit: After looking at the pictures again... was the clutch shaft welded straight to the powershift pump? There should be a splined coupler there.

 

[ajaukema]

Tomorrow I will break down the tractor further and want to find out how de powershift and gearbox is doing.
I think its imaginable that the shaft wasn't 100% straight after the welding, but we will never know
The brass looks very fresh and shiny to me, so maybe it was created just after de shaft has broken and dit some oval like rotations.
To answer the question, yes it is welded together, which wasn't the best idea in my opinion


I added some pictures, the space around the shaft is this normal/ok?

 

[California]

1) Ow! Ow! Ow!)

2) Now I see why it is important to ease PS shifts by slipping the clutch when under load. Maybe PS was designed to be shifted in rice paddy mud (lots of slip), not for a hard surface.

Looks like that tractor has had a hard life. I hope you can get it back together without too much trouble. Please post pics at each stage!

 

[ptsg]

The break after it got welded was to be expected, but why it broke the first time is indeed strange.

That spline coupler also allows for a little bit of play and misalignment between the shafts. If it's welded solid, something will break.

Did it break both times after you own the tractor or just this time?

 

[California]

The break after it got welded was to be expected, but why it broke the first time is indeed strange.

That spline coupler also allows for a little bit of play and misalignment between the shafts. If it's welded solid, something will break.

Good point. Welded solid, the slightest misalignment would thrash the throwout bearing liner. Probably the pump internals too.

 

[ajaukema]

We own this tract for about a year now, and I also suspect it had a hard life, I think it needs more love!
Theres several people driving this tractor, I think some detailed instructions are needed there.

The first time the shaft broke was really soon after we got the tractor and Im not shure what exactly was the case, wasn't there wen it broke, wasn't there when it was "fixed" ahum.
I was very surprised the shaft broke, spent years and years on farms, never heard of this, should be very incidentally!
For me this was also the reason to do it myself this time, just want to know exactly what is going on and the situation of the tractor.
Never done such job on a tractor but as far as it goes, it's pretty straight forward and also fun to do

I can understand that the welding was a temporary (and very bad) fix and wont last for lifetime, but it still makes me wonder how in the first place the shaft broke.
But I guess I won't find the cause for this....

I hope damage to the pump and gearbox is not that big, but I will find out soon!

Any tips on removing and supporting the middle part of the tractor ?

Many thanks already!

Here's some more pictures:

 

[ptsg]

I'm afraid it broke already before you own it and the previous owner just did one of those "fixes" just to get it sold.

Either it broke before or just stripped the splines then someone welded the spline coupler.

Anyway, looks like you'll need to take the input shaft of the transmission off to replace it. I'm not entirely sure on the availability of those, hopefully not too bad.

 

[ajaukema]

Talking about this one right?

 

[ptsg]

Yes, the one that broke the end of.