Lift arms shaft

[Kevin D]

Hello to all,

I am new to the forum, so please forgive my errors, and thanks in advance for any advice. I have a L4600DT with 140 hrs. I noticed during my maintenance when I applied grease to the right hydraulic lift arm that the grease was just shooting out of the splines instead of the other end of the shaft between the arm and chassis. The spline shaft is sticking out about 1/8" past the end of the lift arm. My question: Is that normal, and if not, is it an o-ring issue or could there be something wrong with the shaft? How hard is it to remove the shaft, and does anyone know of a video to how to do repairs? Sorry it is so wordy.

 

[RCW]

Kevin - - a picture would help greatly. Not familiar with an L4600DT.

That said, when you say "right hydraulic lift arm," I think you're talking about the Rock Shaft??

The Rock Shaft would be parallel to the rear axle, and extend both directions from the center housing??

The upper links side onto the rock shaft via grooves. Those upper links then connect to the side/lift links, that pull up the lower lift arms.

I tried to post a parts diagram, but I'm not that smart.....

If your trying to grease a part of the Rock Shaft, I wouldn't want grease to the other side, as in the center of the housing is an open cavity, where the piston for the 3 PH is located. You don't want that filled with grease.

 

[NCL4701]

Hello to all,

I am new to the forum, so please forgive my errors, and thanks in advance for any advice. I have a L4600DT with 140 hrs. I noticed during my maintenance when I applied grease to the right hydraulic lift arm that the grease was just shooting out of the splines instead of the other end of the shaft between the arm and chassis. The spline shaft is sticking out about 1/8" past the end of the lift arm. My question: Is that normal, and if not, is it an o-ring issue or could there be something wrong with the shaft? How hard is it to remove the shaft, and does anyone know of a video to how to do repairs? Sorry it is so wordy.

I don’t know for a 100% fact on a L4600DT. I do know there’s a grease fitting on the ends of the rock shaft on my L4701 and the grease “overflow” comes out between the center housing and the lift arm on the rock shaft. If that’s what it’s doing, I wouldn’t be concerned about it. Having somewhere for the old grease to be forced out allows you to put new grease in without disassembling the rock shaft, so it isn’t a bad thing. (If that’s what yours is doing.)

 

[Kevin D]

Thank you RCW for your response. I'm going to add a photos of the arm and if you blow it up a little you will see the shaft sticking out a little. I believe the grease is kept out of hydraulic cast by seals, but I'm only guessing, that they're o-rings on the shaft holding grease in and dirt out. I could be totally wrong. Any additional information would be helpful. I'm closing in on my 60s, and I'm not a mechanic, but wife said, she just got faith in my toolbox when I told her what the hourly charge is at the Kubota Dealership! Thanks again

 

[Kevin D]

I don’t know for a 100% fact on a L4600DT. I do know there’s a grease fitting on the ends of the rock shaft on my L4701 and the grease “overflow” comes out between the center housing and the lift arm on the rock shaft. If that’s what it’s doing, I wouldn’t be concerned about it. Having somewhere for the old grease to be forced out allows you to put new grease in without disassembling the rock shaft, so it isn’t a bad thing. (If that’s what yours is doing.)

The grease use to flow exactly as you describe, but now it it coming right back out on the end with the grease fitting. None is coming out now on the other end of the arm.

 

[Kevin D]

The grease use to flow exactly as you describe, but now it it coming right back out on the end with the grease fitting. None is coming out now on the other end of the arm.

Thank you NCL4701

 

[NCL4701]

Ah, looking at the photos, I understand a bit better. Yeah, sometimes mine does that, too. I figure to get from the grease fitting in the center of the shaft to the other side of the lift arm OR to flow around somehow to the outside of the shaft, it has to be flowing somewhere so I wouldn’t mess with it. If one of the service tech types on here says different I would go with whatever they say, but I’d keep greasing it and otherwise leave it be.

 

[Dave_eng]

There should be a grease fitting on either end of the shaft. Check closely for remnants of broken one

Dave

 

[Kevin D]

There should be a grease fitting on either end of the shaft. Check closely for remnants of broken one View attachment 62716

Dave

Thank you Dave! I couldn't find any assembly drawings. Part ID #150 is an end plate that bolts on the left side of the shaft. Is there a drawing for the right side? It looks like a ring clip around the shaft. Kubota said, there is no end cap on right side.

 

[Kevin D]

Ps.

Thank you Dave! I couldn't find any assembly drawings. Part ID #150 is an end plate that bolts on the left side of the shaft. Is there a drawing for the right side? It looks like a ring clip around the shaft. Kubota said, there is no end cap on right side.

There is a grease fitting on the other side that takes grease as it should. All excess grease is pushed out between arm and housing.

 

[Dave_eng]

What you have to understand is the purpose of #150 and why it only exists on one end of the lift rod shaft.

The 3 pt hitch needs a way to tell the position of the 3 pt hitch height. It uses this knowledge to cut off hydraulic pressure once the lift arms reach max height.

The part #150 is where the feedback rod connects to the lift arm shaft.

Dave

 

[Kevin D]

What you have to understand is the purpose of #150 and why it only exists on one end of the lift rod shaft.

The 3 pt hitch needs a way to tell the position of the 3 pt hitch height. It uses this knowledge to cut off hydraulic pressure once the lift arms reach max height.

The part #150 is where the feedback rod connects to the lift arm shaft.

View attachment 62724

Dave

Thanks Dave, you have been extremely helpful. I'm probably wording this poorly. I'm still trying to figure out what has failed, fallen off or changed to cause the grease not travel to the opposite side of the arm (2 1/2" or so) it's not lubricating the rockshaft under the arm at this point. I really don't remember seeing the spline teeth extending past the housing of the arm. Could the rockshaft shift?

 

[Fordtech86]

I think I am reading this right....it sounds like it has old dried up grease in the splines thats keeping in from flowing through to the other side and its following the path of least resistance which is back out the end where the grease fitting is.

Just an observation from reading this

 

[GeoHorn]

Dave_eng, in post #8, showed WHY this is a puzzle to the OP. The grease is NOT supposed to flow out the other end of the rock-shaft when only one end is greased. There should be TWO zerk fittings…one on Each End to grease the rock-shaft.

My M4700 is similar…. one zerk on the end just like an L4600DT…. and one in the middle of the rock-shaft housing to grease the rest of the mechanism.

 

[Fordtech86]

Reading comprehension was not my thing, but I believe this is what Op is trying to get at...

when he greases the right side arm that grease is not flowing through to this point circled in red

But instead its pushing out the end where the fitting is. Sounds like when he greases the left arm from the left side it does?

 

[NCL4701]

As anyone who read my posts above knows, I haven’t had this mechanism apart so I don’t know what the internals look like (aside from the exploded parts diagram above). As the parts diagram shows, there’s a zerk on the center of the rock shaft end on both ends, same as some of the bucket pins on the loader.

For the loader pins, I know they have a blind hole bored on the longitudinal axis of the pin which is intersected by holes bored perpendicular to the pin’s axis which creates a channel for the grease to travel from the zerk to the space between the pin and the pin socket on the loader about midway through the socket. I’m assuming there’s a similar hole bored in the center of the rock shaft which directs the grease somewhere. Doesn’t make a lot of sense to me for grease to be necessary between the rock shaft and lift arm as that’s a splined connection such that the arm isn’t rotating on the shaft (and wouldn’t achieve the desired function of it did).

Which leads to a question I’ve had ever since I started greasing that zerk “per the manual”. In this assembly, where is the grease supposed to go once it travel from the zerk?

Seems like the answer to that question would be instructive in determining whether the exit point of the excess grease is indicative of a problem.

My experience has been that the grease often exits the inside of the lift arm at the joint between the arm and the shaft but sometimes exits the outside edge of the arm as shown in the OP’s photos. My possibly ignorant assumption has been that there are perpendicular holes in the shaft which intersect the longitudinal hole with the zerk at the end to direct grease entirely past the outer splined section of the shaft where the arm attaches end into the rotating joint between the shaft and housing. If that is the case, whether the grease exits between the housing and arm or the end of the shaft is irrelevant. Either way, the grease has to go through the internal channels to the rotating part of the joint where it’s needed and it exits along the path of least resistance which could be the joint between the housing and arm if they aren’t butted up tight or could be the end of the shaft if they are butted up tight.

I am well aware I’m making some assumptions and could be thinking completely wrong on this. Don’t know how I could confirm the actual routing of the grease channels without removing the rock shaft and I have no plans to do that.

If anyone knows how the grease is routed through the rock shaft, it would be quite helpful.

 

[Dave_eng]

The design typically takes care of getting the grease to where it is needed which in your case is into the dimples on the bearing I have marked up.

How the excess grease exits is not a concern.

The two O rings outboard of the dimpled bearing would be to keep dirt and water out.

I you were to remove the grease fitting and use a thin wire to see how deep the grease passage is I think you will find it ends about the middle of the bearing.

A lot to say that if the fitting is accepting grease and with only 140 hours you have no problems needing attention

Dave

 

[NCL4701]

T

The design typically takes care of getting the grease to where it is needed which in your case is into the dimples on the bearing I have marked up.

How the excess grease exits is not a concern.

The two O rings outboard of the dimpled bearing would be to keep dirt and water out.

View attachment 62731

I you were to remove the grease fitting and use a thin wire to see how deep the grease passage is I think you will find it ends about the middle of the bearing.

A lot to say that if the fitting is accepting grease and with only 140 hours you have no problems needing attention

Dave

Thank you. I know I’m not the OP but your explanation is much appreciated.

 

[Kevin D]

I think I am reading this right....it sounds like it has old dried up grease in the splines thats keeping in from flowing through to the other side and its following the path of least resistance which is back out the end where the grease fitting is.

Just an observation from reading this

I think I am reading this right....it sounds like it has old dried up grease in the splines thats keeping in from flowing through to the other side and its following the path of least resistance which is back out the end where the grease fitting is.

Just an observation from reading this

Unfortunately, it is only the clean grease. It looks like an extruder coming out every spline gap.

 

[Kevin D]

Reading comprehension was not my thing, but I believe this is what Op is trying to get at...

when he greases the right side arm that grease is not flowing through to this point circled in red

View attachment 62730
But instead its pushing out the end where the fitting is. Sounds like when he greases the left arm from the left side it does?

Yep, what he said! Thank you for clearly explaining and applying the visual aid to my problem.