Yanmar 155D Right Front Axle Assembly

[Berdo]

Again, we inherited this tractor. I never owned one before, and I’m not tractor-savvy. I was told the PO had flipped the tractor over on its right side some time ago. The PO rarely drove it. When I drove it, the RF wheel would go straight for a little while, then start hunting. The LF kept true, but the RF would kinda wander, badly, like probably 25 degrees, from the LF tire. Directional control was very difficult. Both L and R kingpins appear okay. Steering linkage is okay. Steering gearbox is okay. I separated the RF tie rod from the attachment, and then moved the RF tire through its entire L - R travel. I could feel an area of loose travel. No weird sounds or grinding. I’m afraid something inside of the front axle assembly is broken, or sheared, but I’m not sure. And I’m kind nervous about dismantling the whole assembly to go exploring. I’ve gotten the assembly somewhat apart, but am afraid to go much further until I gain bit of insight and confidence. Any thoughts?

(Photo shows assembly I’m trying to describe, except ours is the right side)

 

[bmaverick]

Again, we inherited this tractor. I never owned one before, and I’m not tractor-savvy. I was told the PO had flipped the tractor over on its right side some time ago. The PO rarely drove it. When I drove it, the RF wheel would go straight for a little while, then start hunting. The LF kept true, but the RF would kinda wander, badly, like probably 25 degrees, from the LF tire. Directional control was very difficult. Both L and R kingpins appear okay. Steering linkage is okay. Steering gearbox is okay. I separated the RF tie rod from the attachment, and then moved the RF tire through its entire L - R travel. I could feel an area of loose travel. No weird sounds or grinding. I’m afraid something inside of the front axle assembly is broken, or sheared, but I’m not sure. And I’m kind nervous about dismantling the whole assembly to go exploring. I’ve gotten the assembly somewhat apart, but am afraid to go much further until I gain bit of insight and confidence. Any thoughts?

(Photo shows assembly I’m trying to describe, except ours is the right side)

sooo, you are saying this then.

 

[ponytug]

Again, we inherited this tractor. I never owned one before, and I’m not tractor-savvy. I was told the PO had flipped the tractor over on its right side some time ago. The PO rarely drove it. When I drove it, the RF wheel would go straight for a little while, then start hunting. The LF kept true, but the RF would kinda wander, badly, like probably 25 degrees, from the LF tire. Directional control was very difficult. Both L and R kingpins appear okay. Steering linkage is okay. Steering gearbox is okay. I separated the RF tie rod from the attachment, and then moved the RF tire through its entire L - R travel. I could feel an area of loose travel. No weird sounds or grinding. I’m afraid something inside of the front axle assembly is broken, or sheared, but I’m not sure. And I’m kind nervous about dismantling the whole assembly to go exploring. I’ve gotten the assembly somewhat apart, but am afraid to go much further until I gain bit of insight and confidence. Any thoughts?

(Photo shows assembly I’m trying to describe, except ours is the right side)

So how far have you gotten the assembly apart? Have you pulled the knuckle arm off? When you have the front wheel off the ground how much can you pull it in/out? Is it leaking oil?

There are a few videos on YouTube on 4wd tractor front knuckle disassembly to help you get the lay of land, so to speak...I think "Marty T" did one awhile back. Not a Yanmar, but similar design.

All the best,

Peter

 

[winston1]

Splitting at the knuckle is not complicated. After that it can be. Yanmar KNuckle Seal Replacement Instructions.

 

[California]

I was told the PO had flipped the tractor over on its right side some time ago. ... the RF would kinda wander, badly, like probably 25 degrees

I don't understand how the wheel can wobble that far when the tie rod is intact. Anybody have an explanation?

 

[Harry in Ky]

My guess is the item labeled knuckle arm (L) is loose on the spindle (or whatever part it's attached to) as in a sheared key, damaged splines, etc. Whatever locates in place.

 

[California]

My guess is the item labeled knuckle arm (L) is loose on the spindle (or whatever part it's attached to) as in a sheared key, damaged splines, etc. Whatever locates in place.

That makes more sense than massive internal damage. And would be far simpler to remedy.

Weld it back together!

 

[Dman1981]

If it’s already broke how much worse can you make it
There is so much information online
And e books available buy one read up on it and tear it apart
A good mechanic never says can’t
Just bad engineers

 

[Berdo]

sooo, you are saying this then.

View attachment 834348

All I need to do is turn the tractor around 180 degrees…

 

[Berdo]

So how far have you gotten the assembly apart? Have you pulled the knuckle arm off? When you have the front wheel off the ground how much can you pull it in/out? Is it leaking oil?

There are a few videos on YouTube on 4wd tractor front knuckle disassembly to help you get the lay of land, so to speak...I think "Marty T" did one awhile back. Not a Yanmar, but similar design.

All the best,

Peter

The assembly is off the axle. I have not yet split the knuckle (I think that means to separate the upper and lower half?). When off the ground, the wheel did not slide in or out at all. No oil leaks. With the tie rod disconnected, the steering wheel and left assembly operate smoothly. I’ll give the video a look. Thank you for your reply.