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.

 

[bmaverick]

PTO shaft damage can occur with misapplication overloads and shock loads.

With that said, an overrun clutch could of saved the day. I tend to do a bunch of pasture brush mowing. Even with the stump-hopping ability of the mower, there are times it hits something so fast and hard, the engine just stops running. BUT, the PTO keeps spinning from the momentum. There are so many times the overrun clutch has saved things from serious damage, even damage to the PTO shaft and internals.

Once the shaft is fixed, check Fredrick's or Hoye for the overrun clutch.

Over-running coupler - OR-66 - Fredricks Equipment Parts - Your home for Yanmar, Mahindra, and Bad Boy Mower parts!

 

[winston1]

The 186 has a built in over run clutch.

 

[bmaverick]

The 186 has a built in over run clutch.View attachment 673223

Is it possible to fail?

 

[California]

Is it possible to fail?

The internal over-run 'clutch' (ratchet) clicks same as a bicycle coaster sound when you quit pedaling. Failure would be slip, or locking up. Either is unlikely and shouldn't stress that transmission input shaft.

 

[ajaukema]

The tractor has an overrun clutch for shure, you can hear it when turning the pto to opposite direction by hand.
We don't use the PTO so I don't think it causes the problems.

I drained the hydraulics/gearbox oil, about 15 liters came out, very bad condition so it needs to be replaced.
The manual says it needs 8 liters, quite a difference ain't it?



What do you guys think how much oil is needed?

 

[winston1]

Go by book and dipstick.

 

[ajaukema]

I got some spare parts from a 1510, which was only few minutes away
Shaft and coupler seem to fit, now i have to get to de PS pump.
Now Im stuck removing the middle part from the tractor.
Removed all bolts and nuts, but it looks like the shaft for the 4WD lever needs to be removed as well.
The lever is off, but no idea for the next steps.
Any who knows how to do this?

 

[bmaverick]

Go by book and dipstick.

I would agree with Winston's input here. Why? Because the hydraulic case area could hold more fluid does not mean it should. Going over can have problems too for the return fluid to flow back inside during operation.

My YM machine is bigger. It took 19 quarts (18L) to fill it. Takes a tad more IF the model is 4WD and has the optional power steering.

Yes, your capacity for the YM186D is 2.1-gallons or 7.9L to fill it.

Wish I could give you input on how to split the tractor. Mine is not 4WD.

 

[ajaukema]

Finally I made it:





Ive got another pump from a 1510D, sadly the splines on the backside don't match



So have to spend some more time on finding spare parts....

 

[radios1]

it's AMAZING that an 18 HP.engine could break that shaft if it was properly made, maybe Yanmar has a recall on it?..