Yanmar/F935 rubber coupler/isolator

[canucklehead]

I have the same issue and I tried rotating my isolator a few different ways to line it up. It still ended up a bit cocked by the time I tightened it to the pulley.

 

[kuboman]

The motor mounts sag as they wear with age and this throws out the alignment of the shaft. It is critical for long transmission life and also of the coupler. This is a severe design flaw on JD's part and I am sure they have gone away from it on subsequent models. You can try shimming the engine but the ultimate fix is new motor mounts. You best sit down when you price them. One of the reasons I traded my F935's off.

 

[canucklehead]

thats good info, thanks. mostly rear motor mounts is what I'm hearing. In your expereince, has it been all 4, or just rears?

I saw price...looks to be around $75 each...OUCH!! I may try shims.

It's really hard to obviously notice motor mounts being worn. The misalignment seems to be biggest indicator.

 

[kuboman]

thats good info, thanks. mostly rear motor mounts is what I'm hearing. In your expereince, has it been all 4, or just rears?

I saw price...looks to be around $75 each...OUCH!! I may try shims.

It's really hard to obviously notice motor mounts being worn. The misalignment seems to be biggest indicator.

Unless something has been bent (doubtful) it is worn motor mounts. If you have new ones to compare to it will become obvious. It maybe the rears are worse but it is a bit of a deal to change so I would recommend to bite it and do them all. They will all be worn some and it does not make sense to go to the trouble and not have it perfect. Misalignment causes there to be side thrust on the small needle bearings on the input shaft to the transmission. They are very small and not meant to have side thrust. When they fail it sends debris through the whole tranny in a matter of seconds and then you have a really big bill. Just my opinion/experience.

 

[kuboman]

thats good info, thanks. mostly rear motor mounts is what I'm hearing. In your expereince, has it been all 4, or just rears?

I saw price...looks to be around $75 each...OUCH!! I may try shims.

It's really hard to obviously notice motor mounts being worn. The misalignment seems to be biggest indicator.

Unless something has been bent (doubtful) it is worn motor mounts. If you have new ones to compare to it will become obvious. It maybe the rears are worse but it is a bit of a deal to change so I would recommend to bite it and do them all. They will all be worn some and it does not make sense to go to the trouble and not have it perfect. Misalignment causes there to be side thrust on the small needle bearings on the input shaft to the transmission. They are very small and not meant to have side thrust. When they fail it sends debris through the whole tranny in a matter of seconds and then you have a really big bill. Just my opinion/experience.

 

[canucklehead]

great advice. I just put 3 washers on EACH side of the 2 rears and that seems to have it aligned much better. I only have 3/4 of a bite on the top motor mount nuts, so I will order new ones all-round.

the RF motor mount nut will not crack loose with my impact gun. might have to heat it up or try to zip cut it.

 

[kuboman]

great advice. I just put 3 washers on EACH side of the 2 rears and that seems to have it aligned much better. I only have 3/4 of a bite on the top motor mount nuts, so I will order new ones all-round.

the RF motor mount nut will not crack loose with my impact gun. might have to heat it up or try to zip cut it.

You might want to check the slack on the input bearing to the transmission. It is pressed into the charge pump which is easy to remove and change the bearing. The other end of the shaft is buried in the tranny and requires major tear down.

 

[canucklehead]

how would I check that? wiggle on the driveshaft and feel for slop/play where driveshaft goes into tranny? should it be zero tolerance/movement?

 

[kuboman]

how would I check that? wiggle on the driveshaft and feel for slop/play where driveshaft goes into tranny? should it be zero tolerance/movement?

Grab the shaft right at the transmission and lift or push and pull at right angles to the shaft in all directions. If there is any movement you will feel it, if you can actually see movement you are getting quite a bit. Also check the seal to see if it is starting to sweat oil. If it is then you have an indication that the seal is wearing likely because of excessive movement in the bearing. Both the bearing and the seal can be changed and if there are any indicators of wear it would be a good idea. The shaft may be worn too but that requires a tear down to change. The bearing is the most likely to fail and that is an easy repair.

 

[canucklehead]

thanks Kuboman.

I have a T1560 with grass catcher, and the best push/self-propelled mower I've ever owned..by a mile: Kubota W5021 self propel.... pushing 25-30 years old and it still pulls me around.