broken lift arm shaft

JC-jetro · May 1, 2011

jinman said:
JC, I agree with you on most everythng, but this one has me scratchin' my head. I just don't see why the spline position matters. After you get the shaft in the lift lever, you run it to the top position and put on the lift arms. What could possibly be wrong with that? Maybe it's the upper limit sensing mechanism that has to be located in a specific position. I just don't know and I'd love to know what it is that could possibly be out of position. Is there anything keyed? I don't think so. Enquiring minds want to know. . . .

Good morning Jim,

As you said the relative position of (shaft spline to lift arm) and (shaft spline internal arm) make no difference whatsoever and they are not keyed together.

The point that I'm making is what is the relative position of external arm and internal arm is as the splined shaft is set in place. Is the OP has ended up with the same position? That's the calibration importance. If the internal arm does not sees the full stroke of the lift cylinder then we have an issue. If it is bounds up then we have an issue. Some of the problem was mentioned here by the op after complete installation.

If the lift cover was removed then it would be easy to duplicate both arms relative position. If the cylinder head was removed for inspection again arms relative position could have been duplicated.

what's your take on my statement?

JC,

Edit: more info,

When I changed the piston seal on my tractor I removed implement on the 3 point, I lowered the external arm all the way and proceeded to remove head, piston and cylinder liner. The internal arm was at some position on the bottom. moving the outside arm and internal arm would go up and down. keeping the exterior arm at the lowest point and internal arm could be put at many different positions that could limit max or min piston travel. That's need to be avoided. If we had information like the angle between two arms around 30 degrees then the first installation of external would not matter as the rockshaft splines are uniformly distributed but the install of the next one become very important to duplicate the right angle.

jinman · May 2, 2011

JC-jetro said:
what's your take on my statement?

JC,

I just don't know JC. You have worked with the lift and I have not done anything with mine except adjust the stop. I think the relative position of the arms can be indexed due to the splining on the shaft ends, but it might be off by plus or minus one spline and not be perfect. At the arm's end, one spline might be an inch or more in height and that would be a lot for the 3PH. Someone who does these on a regular basis might be able to do it, but a 1st-timer might have a tough time with it; especially working alone. What I have done is remove the operator platform on a "Dee-lux" model tractor. That job is an old-fashioned butt-kicking and I wouldn't wish that on anyone. If bsstreet can get this close enough to be satisfactory without removing the operator platform, then it is worth a try. I just hope nothing dropped out of position inside when his lift lever went "feral" on him.

JC-jetro · May 2, 2011

jinman said:
I just don't know JC. You have worked with the lift and I have not done anything with mine except adjust the stop. I think the relative position of the arms can be indexed due to the splining on the shaft ends, but it might be off by plus or minus one spline and not be perfect. At the arm's end, one spline might be an inch or more in height and that would be a lot for the 3PH. Someone who does these on a regular basis might be able to do it, but a 1st-timer might have a tough time with it; especially working alone. What I have done is remove the operator platform on a "Dee-lux" model tractor. That job is an old-fashioned butt-kicking and I wouldn't wish that on anyone. If bsstreet can get this close enough to be satisfactory without removing the operator platform, then it is worth a try. I just hope nothing dropped out of position inside when his lift lever went "feral" on him.

Jim,

I think one or two notches might prove critical if it ends up binding the arm at highest or lowest position. if the arms are raised up 1/2" Lower than normal might not be a big issue. What I have no doubt is if I remove the cylinder head I can then stick my arm in there and keep the arm steady. Following is the procedure I'd use to duplicate the angle.

Below is the picture of the front of the lift cover after the cylinder head/liner and piston removed. Ram rod is pinned to the internal arm. With the ram rod resting as it pictured I'd mark the external arm position with putting two witness marks , one on the arm and second on the lift cover side. I'd give no particular attention to splines at all. Once I remove the broken piece I proceed to insert the new rockshaft in without worrying at all on the splines as the splines are symmetrical. I'd use a helper to hold on to the ram rod and steady things out so to avoid binding of rock shaft and splines on the ram rod. Once I'm done with that, I'd rest the ram rod as it was before , hold it steady and in place and install the outside arms where I match up witness mark on the lift arm and side of lift cover. Doing so, I'm not really focused on splines but I'd be duplicating the same angle between inside arm and external lift arm. Pulling the ram rod in and out will change rotation of rockshaft to be avoided. I'm sure there is a written procedure for this. As said before this is a fantastic design by Shibaura. On many makes and model there is no choice, none whatsoever but to remove the whole lift cover

This is when we need RickB to chime in