Yanmar 186D broken shaft

[HoyeTractor]

Are we sure the shaft was ever originally broken and not just stripped? I'm thinking the original failure was stripped splines, then welded, then re-welded. Don't know for sure though but seems very unlikely that shaft would actually break.

 

[ptsg]

Are we sure the shaft was ever originally broken and not just stripped? I'm thinking the original failure was stripped splines, then welded, then re-welded. Don't know for sure though but seems very unlikely that shaft would actually break.

My thoughts exactly. Usually the splined coupler would be the failure point there.

 

[California]

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

Like I said, ease every hard shift by slipping the clutch a little. The jolt of a full throttle shift spooked me the first time I did it, it felt like it would break something - like this.

 

[radios1]

Like I said, ease every hard shift by slipping the clutch a little. The jolt of a full throttle shift spooked me the first time I did it, it felt like it would break something - like this.

that points to a big engineering failure!. it should never be necessary to slip the clutch, and that also wears it out unnecessarily!.. who does that on purpose?.:shocked:

 

[California]

that points to a big engineering failure!. it should never be necessary to slip the clutch, and that also wears it out unnecessarily!.. who does that on purpose?

Maybe I shouldn't have said slip. Disengage for an instant just enough to reduce shock load. Powershift is a straight mechanical connection, engine to wheels, after the internal clutches engage. They engage instantly at high rpm. Owners have shown leaving skidmarks on pavement at each shift like a modified Mustang or something. Not me!

Shifting down at full throttle as a slope gets steeper is one of the advantages of Powershift. I find this little guy (18 engine hp) is very nearly the equal of my YM240 (24 engine hp, manual transmission) because of avoiding the full stop to change gears many times as I move around in my sloping orchard.

I would much rather split the tractor and replace the conventional clutch ahead of the Powershift, (not likely needed) instead of having to repair the Powershift internals, or face the broken shaft we see here.

To conclude, the Powershift just works. At 40 years old I'm going to baby it a little. Replacing the conventional clutch seems a lot easier than risking damage to the PS or that shaft.

 

[ajaukema]

Im working on 2 scenarios:

1 replace the main shaft, splined coupler and PS pump shaft, but hard to find this parts. I asked hoyetractor, not shure if they ship to The Netherlands.



2 I got a clutch disc, main shaft, splined coupler, PS pump from an 1510, almost identical but sadly different splines.



The idea I have is to have a custom shaft for the PS pump which has 186D splines on the output and 1510 splines on de input side.
Green arrows = 1510 parts
Red arrow = custom, 1510 splines
Blue arrow = custom, 186D splines



Or a splined coupler after the PS pump which has 186D splines on the output and 1510 splines on de input side, not shure if that is possible to produce...



What do you guys think?

Any ideas how to open the PS pump? I removed the 2 bolts and the circlip on the output side, but it doesn't open much further than a couple of mm.
Are some steps missing, or does it need more force?

 

[California]

What about using all 1510 parts, including the pump clear up to including the clutch disc? Even if you have to shorten the shaft, this might be simpler.

 

[ajaukema]

What about using all 1510 parts, including the pump clear up to including the clutch disc? Even if you have to shorten the shaft, this might be simpler.

Sadly not possible because the splines on the output side of de PS pump 1510 don't match on the input side of the 186d gearbox.....

So de idea is to have a custom shaft for the pump:



The green side needs 1510 splines, the red side needs 186D splines

 

[ajaukema]

Last week I got the new shaft for the pump:



From this:



To this:



I rebuild the tractor, put a new hydraulics filter on it and added new oil in the transmission/hydraulics reservoir.


At first the tractor seemed to work 100%, but after a while the powershift give some issues, it wont shift in the reverse and 1st gear.
Sometimes it won't shift and sometimes it takes up to 30 seconds and then it shifts into gear.

I suspect it has too little oil in it.

Got 10 liters, filled the filter first and the put the rest in the reservoire.
The manual says it need 8 liters, but I think it needs way more.
Anyone over here who knows how many liters oil this tractor needs?

 

[KWentling]

I would be looking for a suction tube leak. That pump is setting up pretty high so there must be a tube reaching down into the fluid. A leaking connection or hole in the tube might be close to the normal fluid level and under use it sucks some air. The previous "fix" might have been to add fluid until it quit sucking air. Is there no sight glass or dip stick?

 

[CoyPatton]

Last week I got the new shaft for the pump:

View attachment 678212

From this:

View attachment 678213

To this:

View attachment 678214

I rebuild the tractor, put a new hydraulics filter on it and added new oil in the transmission/hydraulics reservoir.


At first the tractor seemed to work 100%, but after a while the powershift give some issues, it wont shift in the reverse and 1st gear.
Sometimes it won't shift and sometimes it takes up to 30 seconds and then it shifts into gear.

I suspect it has too little oil in it.

Got 10 liters, filled the filter first and the put the rest in the reservoire.
The manual says it need 8 liters, but I think it needs way more.
Anyone over here who knows how many liters oil this tractor needs?

Did you clean the suction filter that is inside the reservoir? This is in addition to a screw on filter. If it is restricted, hydraulic fluid flow will be affected. It is low in the reservoir, so fluid loss is a given with its removal (drain first). If your fluid is caught clean, you can reuse it. Access plate should be on the opposite side of the transmission housing from the suction tube going to the spin on filter and pump.

 

[winston1]

Last week I got the new shaft for the pump:

View attachment 678212

From this:

View attachment 678213

To this:

View attachment 678214

I rebuild the tractor, put a new hydraulics filter on it and added new oil in the transmission/hydraulics reservoir.


At first the tractor seemed to work 100%, but after a while the powershift give some issues, it wont shift in the reverse and 1st gear.
Sometimes it won't shift and sometimes it takes up to 30 seconds and then it shifts into gear.

I suspect it has too little oil in it.

Got 10 liters, filled the filter first and the put the rest in the reservoire.
The manual says it need 8 liters, but I think it needs way more.
Anyone over here who knows how many liters oil this tractor needs?

8.4qts, 7.95 liters according to tractor data info.

 

[California]

In addition to the screw-on external transmission filter there's a 'strainer', wire mesh, behind a cover that is at the top-left of the transmission and behind your left ankle. In this photo one of its four little cover bolts is visible, just even with the back of the sheet metal.
https://www.tractorbynet.com/forums...easier-ym186dstep-cargobag20190830_134537-jpg

The strainer (#11) and the large opening it goes into, appear in this Hoye diagram.

My experience was I dumped 1/3 liter oil taking that cover off one of my YM186D's but then for some reason spilled very little on the other YM186D.

And there's a dipstick you can pull out to check the transmission oil level. It's back where the pto shift lever goes into the transmission on the left side.

 

[ajaukema]

I added a little more oil, the dipstick has now a little oil on the tip, so I think it has the right oillevel the powershift now seems to work a bit better.
Also the temperatures makes a difference I guess, after a while when the engine and oil is warm, the powershift is more smooth.

The strainer is in good condition btw, checked this before adding the new oil. Not sure about this suction pipe, where/how can I get access to it?
Is this suction pipe connected to the powershift oil circuit or is it connected to the hydraulic circuit for the 3 point hitch?
I understand the hydraulics and powershift has a shared reservoire
The hitch works fine btw.

So the tractor is basically functioning well, but it is a bit hard to start this tractor, it takes a long time starting before it run.
There is white smoke while starting so to me it looks like the fuel circuit is ok.

I found out this thermostart plug, but Im not shure if its working properly, is there a way to test the plug?

 

[California]

I found out this thermostart plug, but Im not shure if its working properly, is there a way to test the plug?

Twist the key left for 15 seconds. The thermostart and neighboring metal should feel slightly warm.

A replacement Thermostart module looks like a spark plug and is not expensive. Lowest price is about $12 on Ebay. They are universal and are used on other brands also, so they are widely available. The wire will attach with a screw or a slide-on connector, so check which type you need.

As for transmission warmup - what is the transmission fluid you have in it? The original specification, Deere 303, is single-grade oil that is thick when cold. Modern multi-grade UTF - Universal Transmission Fluid - is better for cold weather (and better quality overall).

 

[bmaverick]

Twist the key left for 15 seconds. The thermostart and neighboring metal should feel slightly warm.

A replacement Thermostart module looks like a spark plug and is not expensive. Lowest price is about $12 on Ebay. They are universal and are used on other brands also, so they are widely available. The wire will attach with a screw or a slide-on connector, so check which type you need.

As for transmission warmup - what is the transmission fluid you have in it? The original specification, Deere 303, is single-grade oil that is thick when cold. Modern multi-grade UTF - Universal Transmission Fluid - is better for cold weather (and better quality overall).

JD-303 is banned is several states and has been obsoleted over 45 years ago. For the YM Series and the JD 50 + 70 Series machines, J20C is the ideal fluid to use. Deere and Yanmar worked on that specification together.

Yanmar compact tractors and machines are not old enough to even had used JD-303. Those were the very old and large JD machines made in the US and in Germany.

Here is the history of how the oils went.
Perilously Obsolete: The Dangers of 33 Tractor Hydraulic Fluids | TractorLife

JD303, then to J14. J14 moved up to J20A. Later J20A had to be obsoleted and J20C/J20D became the golden standard.

JD303, J14 and J20a are in fact - - - > low-quality fluids. That is why these are sold for CHEAP in the stores.
Lubrizol’s testing of these fluids has shown an average 25 percent viscosity increase over 100 hours of measuring oxidative stability. In other words, these fluids have been shown to thicken during extended use, which can result in many problems, including erratic or sluggish hydraulic response due to deposit formation and strain on the hydraulic system.

 

[rScotty]

The strainer is in good condition btw, checked this before adding the new oil. Not sure about this suction pipe, where/how can I get access to it?
Is this suction pipe connected to the powershift oil circuit or is it connected to the hydraulic circuit for the 3 point hitch?
I understand the hydraulics and powershift has a shared reservoire

The suction pipe is the one that runs from the strainer cover up to the front of the tractor where it connects to the hydraulic pump. It is often partly metal and other parts of the line can be rubber because it doesn't carry any pressure. However, if they suck air into the suction line then it makes for problems that are hard to diagnose. As originally built, all the hydraulics share the same reservoir.

Old tractors can be hard to start. Particularly diesels. Find some way to heat it up a little before starting.
rScotty

 

[winston1]

The suction pipe is the one that runs from the strainer cover up to the front of the tractor where it connects to the hydraulic pump. It is often partly metal and other parts of the line can be rubber because it doesn't carry any pressure. However, if they suck air into the suction line then it makes for problems that are hard to diagnose. As originally built, all the hydraulics share the same reservoir.

Old tractors can be hard to start. Particularly diesels. Find some way to heat it up a little before starting.
rScotty

Probably not but might be talking about #31 here.

 

[CoyPatton]

Typically on the yanmars, the access plate to remove the screen is on one side of the transmission and the suction pipe/hose is on the opposite side at the same level. If you can not id it that way, go to your pump on the engine and trace the lager of the two (2) lines from the pump back to the transmission housing. If yours is equipped with a spin-on hydraulic filter, you can jump your trace point to its mount housing and then back to the transmission housing.
Typically, you will find a mix of rubber hoses and hard lines as a part of the suction lines. The rubber are there fir 2 primary purposes, 1) to absorb vibrations to protect the metal lines fir damage (not necessarily a 100% protection as my machine is right at 40 yrs old although not that many hours showing on hr meter) 2) it is easier to remove than a hard metal attached line at potential replacement parts, the spin-on filter housing or to replace a damaged metal line. Unfortunately rubber hoses especially 40 yr old rubber breaks down.
Also unfortunately, you are not likely to find a compromise is this while the engine is running, as it will probably experience a suction effect pull air into the lines not fluid coming out. If you suspect a leak in this system, clean the line, secure paper under the lines, and look for oil drops on the paper, then chase those drip marks on the line realizing that a thick fluid may travel down hill before getting heavy enough to drop.

 

[ajaukema]

Small update, today I went to the tractor for a quick visit on the way home from work (the tractor is not at home).

- Tested the thermostart plug, turned the key to the left and after a short time the metal on the air-intake side gets warm, so that is OK!
I will check the fuel cup, fuel flow into the air-intake later (takes more time and left my tools at home)

- Yesterday the tractor again didn't shift into the reverse gear.
Today I checked the lever and it has lots of play, so Im thinking about removing this metal cap/guide from the lever and check if this helps in orde have the spool in the exact positions.

I believe the hydraulics are basically ok, the 3 point hitch works very good all the time, the 2nd, 3th and neutral position form the powershift always work fine.