Yanmar 187D - 4WD just quit on me

DWeinreich · Feb 20, 2011

Forgot one thing, keep track of the shims between the pinion holder and axle case. Also the shims that are part of the center pin bolt plate.

normde2001 · Feb 21, 2011

It would appear that pinion is done for, probably the ring gear also. They have been running loose for a long time.

DWeinreich · Feb 21, 2011

Normde2001 - what do you see in the photo that indicates the pinion is shot? It all worked fine before I busted the pinion holder. The teeth still show original mill marks and when I test fit the pinion yesterday it felt like everything engaged without grinding.

normde2001 · Feb 21, 2011

Could be wrong , but it appears to me that the back edge, (big end), of the teeth are worn to a pretty sharp edge. May not matter so much on a slow moving gear-set. you can tell better after clean-up.

Car Doc · Feb 21, 2011

I agree with norm I see a lot of taper in the pinion gear teeth they are not built that way it wore enough to look like that and the ring gear would be worn as well.

Not saying it wont work if the back lash and pinion depth are right (as they can be for 20-30 years old) but that may be what blew it up is the pinion climbing over a ring gear tooth for some reason like a bad bearing?. Close inspection should prove that, one tooth on either part of the set should show a slight abnormality.

284 International · Mar 10, 2011

DWeinrich, have you made any progress or had any resolution?

DWeinreich · Mar 10, 2011

Haven't had time lately to work on it. But I've got the bits and pieces gathered up to go at it whenever I can get a free Saturday with decent weather. The next step is to weld the tabs back on. I will update the thread then. Thanks again for all the helpful advice to date.

DWeinreich · Mar 19, 2011

Got back to it today and welded the broken ears back on the pinion holder. The nickel welding rod wasn't easy to work with but several passes with grinding in between got a considerable amount of weld in the area. 1/8" and 3/32nd rod is what I had and ran it on an AC welder at around 80 amps. Working around the bolt heads made it a little tricky. I decided to use the axle housing itself as a jig to keep all the pieces in alignment. First I took out the oil seal so it wouldn't fry from the heat.

Everything is put back together now except one set of roll pins. So, tomorrow I'll finish 'er up and find out if this repair was worth the trouble. Keeping my fingers crossed...will post the result.

DWeinreich · Mar 20, 2011

Sorry to say the repair was a bust. After reassembly the test drive revealed a nasty clatter from the front axle. I suspect the bevel gear and pinion are not meshing properly. Since I depend on 4wd not sure what to do next since parts are probably not available for this 25year old machine. May have to bite the bullet and get a replacement tractor.

California · Mar 20, 2011

Before you give up - I would put it up on stands, and listen to verify the origin. Maybe the racket is over in a hub. Maybe you (or an experienced automotive shop) could shim the ring/pinion into better alignment, or add material to rebuild that pinion gear.

I expect the parts are out there somewhere. Manuals for some models show different gearsets for different tire combinations, so make sure of the right ratio!

Did you already survey all the parts dealers and junkyards? How about Len? He can get near anything out of Japan if it's worth paying for the hours of research and calls he would need to locate the parts. In fact he has posted that he can have gears made from scratch.

And if you finally decide to move on, please offer it here. Somebody might have a 187 down, waiting for unrelated parts.

I'm sorry to hear all that work didn't solve it.