broken lift arm shaft

[bsstreet]

Previous lurker, but now new member due to unusual brakedown. This is on a 2001 TC35d with hydrostatic transm. Owned since 2004, 950 hours; the lift arm shaft broke within the splined receiver yolk of the lift arm on the left side. This happened a day after using the boxblade to dig out a small pond, but I have moved many hundreds of yards of dirt over the past 7 years. I can't believe the almost 2" diameter shaft would break without a catastrophic high speed hangup, but it did. A friend that looked at it said there was evidence of crystallization within the break (whatever that means).

I have searched tractorbynet and elsewhere for info on changing the shaft to no avail. Two different NH dealers quoted >$1300 for the repair because they said they had to remove the lift cover (after removing fenders/seat/rops/fueltank...) to replace the shaft.

The shaft moves sideways readily with light tapping on the broken side. I am wondering if i could just disconnect the rops and lift it enough to be able to slide the old one out and new one in without taking the lift cover off and all that involves. Looking at a parts diagram the center splined area of the shaft fits through a splined "arm" inside the hydraulic cylinder, but would this move out of position when the old one was removed such that the new one could not be slid in place? Also, should I replace the springs, o-rings and bushings on either side of the shaft even if they look OK.

Any advice appreciated. Parts diagram attached.

Thanks

 

[slowzuki]

Common enough to break with heavy use over time. The term crystallization is a BS term used by folks you don't know what a hardened shaft looks like when it breaks.

The crack usually starts near on the the splines sharp groove shoulders and can take a few different shapes.

Hooking the corner of a box blade or other uneven load puts a twisting load on this shaft and can sometimes pop it.

1300$ is a lot, there isn't anything very fancy under that cover if you are used to hydraulics. You could probably fish the new one through using a bar from the other side to keep the splined centre arm from dropping. Certainly worth a try, worse case you have to pay someone to finish.

EDIT you do have to index the angle so if the hitch its at full droop to start, the arms are reinstalled at full droop, and the lift rod for the 3 point position sensing has to be adjusted so the hitch doesn't keep trying to raise or not lower, marking original location should work.

 

[Localmotion]

I'm no mechanic and am not familiar with the TC35d , but I can testify that what slowzuki says is true - it shouldn't be that difficult.

Two years ago I had exactly the same happen on my Siromer (Jinma) 204S - if you aren't able to pass the new one through you should be able to gain access to centre arm via the top of the back axel. A lot of machines have at least an inspection plate or removable "top" located under the seat. If so you will need to remove the seat - but probably worth doing and having a look rather than spending big bucks for someone else to do it for you?

Intrestingly enough I have a similar problem now on my Fiat New Holland 50-86. The link arm has dropped - I think it has stripped the spline. I'm going to have a look tomorrow (or possibly Sunday if raining), so will let you know how I get on...

I should also say that in both cases it was my 2 metre grader that broke the tractor! We do a lot of road grading and laying of Zahora (metal) - if the camber is server then a lot of weight is being pulled off centre, which turns into force onto one link arm only when the blade is lifted.

Good Luck :thumbsup:

 

[JC-jetro]

Previous lurker, but now new member due to unusual brakedown. This is on a 2001 TC35d with hydrostatic transm. Owned since 2004, 950 hours; the lift arm shaft broke within the splined receiver yolk of the lift arm on the left side. This happened a day after using the boxblade to dig out a small pond, but I have moved many hundreds of yards of dirt over the past 7 years. I can't believe the almost 2" diameter shaft would break without a catastrophic high speed hangup, but it did. A friend that looked at it said there was evidence of crystallization within the break (whatever that means).

I have searched tractorbynet and elsewhere for info on changing the shaft to no avail. Two different NH dealers quoted >$1300 for the repair because they said they had to remove the lift cover (after removing fenders/seat/rops/fueltank...) to replace the shaft.

The shaft moves sideways readily with light tapping on the broken side. I am wondering if i could just disconnect the rops and lift it enough to be able to slide the old one out and new one in without taking the lift cover off and all that involves. Looking at a parts diagram the center splined area of the shaft fits through a splined "arm" inside the hydraulic cylinder, but would this move out of position when the old one was removed such that the new one could not be slid in place? Also, should I replace the springs, o-rings and bushings on either side of the shaft even if they look OK.

Any advice appreciated. Parts diagram attached.

Thanks

Are you talking Rockshaft Item #28 ? if so , then the answer is no. The rock shaft is splined to #48. and is supported by #28. Depending where the breakage is the partial rock shaft can come out of the lift cover. Pic below might help. it is from my 1700 but design is exactly the same on both tractors.

JC,

 

[bsstreet]

#28 is the part that is broken. It is broken at the point where it is inside part #18; which is just outside the lift housing.

Thanks

 

[JC-jetro]

#28 is the part that is broken. It is broken at the point where it is inside part #18; which is just outside the lift housing.

Thanks

So your lift arm is flopping around? I think the answer is still " No " unfortunately.

Are you sure if some of the spline is broken of or the whole shaft is twisted off? Any pics? There is no way to withdraw rockshaft #28 out of the lift housing without losing lift arm dropping in to the rear diffy. I doubt if it would even easy to slide out he rockshaft without some brut force.

JC,

 

[slowzuki]

Why not? It looks to be retained on one side by a circlip. You can keep the splined part from falling easily from the other side. I just replaced part of my MF's pto and had to do it with a splined gear.

If the spline twisted when it broke, you won't just pop out the piece but maybe you're lucky.

I had the arm off my Kubota this winter, and the worst part was getting the arm off the spline. Had to heat the arm.

So your lift arm is flopping around? I think the answer is still " No " unfortunately.

Are you sure if some of the spline is broken of or the whole shaft is twisted off? Any pics? There is no way to withdraw rockshaft #28 out of the lift housing without losing lift arm dropping in to the rear diffy. I doubt if it would even easy to slide out he rockshaft without some brut force.

JC,

 

[JC-jetro]

Why not? It looks to be retained on one side by a circlip. You can keep the splined part from falling easily from the other side. I just replaced part of my MF's pto and had to do it with a splined gear.

If the spline twisted when it broke, you won't just pop out the piece but maybe you're lucky.

I had the arm off my Kubota this winter, and the worst part was getting the arm off the spline. Had to heat the arm.

how could you hold on to the lift arm internally if you are able to slide out complete rockshaft. The clip only keeps the lift arm from coming off the shaft. What pushes the ram rod internally is rotation of rockshaft along with the internal lift arm. you withdraw the shaft and what is holding the internal lift arm?

Jc,

 

[bsstreet]

thanks for the input so far; i was able to take a couple of photos. one showing the broken shaft and liftarm together, the other showing the opposing lift arm move out a little after taping on the broken side. Hope this clarifies.

Thanks again, Bob

 

[Jerry/MT]

how could you hold on to the lift arm internally if you are able to slide out complete rockshaft. The clip only keeps the lift arm from coming off the shaft. What pushes the ram rod internally is rotation of rockshaft along with the internal lift arm. you withdraw the shaft and what is holding the internal lift arm?

Jc,

I think it might be do able with several big IF's.

If the piston is fully retracted then, since the piece that rotates the rockshaft (#48, rockshaft actuator), is pinned to the piston rod, the pin will keep the#48 from falling down. It may try to rotate about the piston's axis but a small rod placed through the hole in the rock shaft actuator can keep that alligned.


The big IF is can you slide the rockshaft out leaving the rockshaft actuator in place and then slide the new rockshaft through all three holes? You also have to keep #48 in a specific position when it engages the rockshaft. I don't think those bushed holes are a sliding fit. I think they maybe a press fit. IF that's the case, the lift cover has to come off or you need some special tools.