1920 FWD Drive Shaft Worn - Why?

[mroberts5]

(About a New Holland 1920 - 2100hr - 100 w/ me. I usually run 4WD active, not sure of previous owners.)

So I'm just about done w/ my clutch replacement (actually much easier than I expected), and the only parts that's given me a hard time is the FWD drive shaft.

Two issues, one minor, one larger:

Minor: The rear coupling is just about seized on to the output shaft from the transmission. I'm going to remove the drop box to get it off and clean everything up.

Larger issue: The front end of the drive shaft, the front collar, and the input shaft to the front axle are SHOT!

See the pictures below. Not only are the splines worn nearly to nothing, but coupling pin has been banging around so bad that its worn a grove in both shafts and has nearly worn it self out (see photos)

Fixing it is easy (provided I can find the parts), but my main concern is: why did this happen? Something must be out of alignment to cause this kind of wear. Any clues on where to start looking?

I saw one comment on another post about worn axle pivot bushings, but I'm not too familiar with how this will cause the issue.

Thanks.

 

[RickB]

Worn pivot bushings will cause misalignment of the pinion shaft splines, coupler, and driveshaft splines.

The root cause of worn pivot shaft bushings is failure to grease them. $10 worth of grease applied to those 2 zerks over the life of the tractor would have saved several hundred dollars of expense now.

 

[mroberts5]

So I jacked up the front end to see if I can feel any play in the trunion bushings. Of course its hard to tell whats "normal" but I can get a VERY little side to side movement out of it. My first thought was just to replace everything from the drive shaft through the drive pinion set and bushings, buts I'm looking at over $1000 in parts. As I see it here are my options. Any thoughts?

1. Put it all back together and run it until the spline teeth fully shear off. Use 4WD only when required.
2. Permanently attach the drive shaft to the bevel pinion shaft w/ either JB Weld, set screws, pins through shafts or something similar. If I could find some semi flexable but strong epoxy, that would be best.
3. Same as above, but also replace the pivot bushings (only $100 in parts).
4. Go all out and replace it all.

[EDIT]: Instead of using epoxy on the coupling, I could replace it w/ a clamp on coupling. They can handle up to 3000 lb of torque - which should be just fine.

I'm leaning towards option 3. This should prevent any further wear and permanently fix the drive shaft to the input shaft.

Has anyone replace these bushings before? How hard are they to drive out (especially the front one which is in the blind casting?

Thanks.

 

[Fawken]

Looks pretty corroded. The set-up looks a lot like my 1100, except my entire drive shaft is sealed in a tube and has a rubber collar with hose clamps to connect the tube to the transmission. Wondering if the rubber collar was worn out on your machine or if it even had the protection tube?

 

[mroberts5]

Yeah, it was wet and rather rusty. But the front and rear both are and only the front is worn. There's the protective tube, but no rubber collar. I don't see it on the parts breakdown, so I'm not sure if any 1920s have it.

 

[Fawken]

Yeah, it was wet and rather rusty. But the front and rear both are and only the front is worn. There's the protective tube, but no rubber collar. I don't see it on the parts breakdown, so I'm not sure if any 1920s have it.

Well they look kind of like a 6" rubber pipe splicer and it covers the U-joints as well if memory serves. Those splines need to have some end play and if dirt or rust gets on the shaft it will bind up. When I get home from work I'll look in the service manual.

 

[mroberts5]

I don't have any U-Joints.

 

[toddwulf]

We just had our front ring and pinion and all the seals and bearings replaced. Take off the R&P and look for wear on the pinion input shaft that connects to the drive shaft. If you see any wear, identify and fix before it tears up the ring. Complete R&P parts were around $800.

 

[mroberts5]

Just to give an update, I replaced the front and rear bushings as well as the drive shaft and the one worn coupling. The input shaft is worn, but not too bad. I was thinking of JB Welding it on, but ultimately decided not to. Instead I'll make sure to only used 4WD when I really need it.

As for the bushings, they were quite easy. A few tips:

-Don't bother removing the power stearig lines. There's plenty of slack to get the axle dropped.

-Be careful supporting the axle with just a floor jack. It wants to rotate (input shaft down), so either block it or use a tranny jack.

-Removing the bushings isnt too bad. They're both pressed into a blind cavity. You can buy the front in the casting (I did), but really there's no reason to. You can chisel down the bushing split, then get it loose enogh to remove. You'll scratch up the casting, so clean it up with some emery cloth. Then press in the new bushing with a press or vise. I made my own drift out of scrap wood backed by a chunk of steel.


Oh yeah, the new bushings were MUCH tighter than the old ones. My front zerk fitting was bashed up, so I replaced that and bench filled it with grease.

Hopefully all is good now. Thanks Rick for the direction.