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317 driveshaft setscrew


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#1 PEIslander OFFLINE  

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Posted August 30, 2011 - 02:29 PM

I have a 317 with some slop in the connection between the drive shaft and the engine flange. Bearings and universals in the driveshaft appear OK, and are fitted with grease nipples.

There is an allen head setscrew in the drive shaft which was not tightened on the flange. A look at another older 317 reveals a drive shaft with no setscrew. I have read somewhere that this should be just a slip fit, to allow for some expansion, contraction or motor movement.
My question: Should I tighten the setscrew, and remove the slop, or is that asking for trouble somewhere else?

Ron C.

#2 JDBrian OFFLINE  

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Posted August 30, 2011 - 03:51 PM

I had a look at the diagrams for the 317 and it only shows pins on one end of the shaft. No set screws anywhere. It could be that someone has repaired it by using set screws. The strange thing is that on the 314 the pin was later replaced by set screws at the hydro end. However the 314 does not have u joints only some flexible coupler disks. Here are the diagrams.

MP4583_________UN01JAN94.jpg

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#3 PEIslander OFFLINE  

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Posted September 09, 2011 - 10:53 AM

I have had a look at my 314 parts tractor, and it seems to me that the drive shaft does not really fit far enough on to the engine flange adapter, to do a proper job as an expansion joint. The flange is worn. Flattened in one side, near the end, and on the opposite side, where the drive shaft sleeve ended. The key is also worn on one side.
I was wondering how to improve this, and am considering cutting the drive shaft near the center and sleeving it with a slip fitting pipe or tubing. The tubing would be welded or pinned to one end, and fastened to the other portion of drive shaft by two or more pins in the shaft, and thru slots cut in the sleeve. This would allow the coupling at the eng1ne to be made rigid, by pushing it further on, and using setscrew(s).

Any thoughts?

#4 olcowhand OFFLINE  

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Posted September 09, 2011 - 02:29 PM

Have you checked your motor mounts to be sure nothing has moved out of place?

#5 Texas Deere and Horse OFFLINE  

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Posted September 09, 2011 - 02:55 PM

Daniel brings up a very good point, the motor mounts are rubber, to help with vibration and do go bad after years in service. I would check the motor mounts and make sure the engine is sitting square in the frame.

#6 PEIslander OFFLINE  

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Posted September 09, 2011 - 08:04 PM

There is no problem with the motor mounts.

I guess I used a poor wording for my query. The couplings and shafts are totally engaged on both my units. I suspect that the length of the overlap, which is the full length of the fitting, is inadequate to support the shaft, when it must be free to operate as an expansion joint. I would trust the coupling if it were pinned.

Both units have the identical problem, which indicates a design deficiency to me.

Mind you, they are 30 years old, and I expect some wear in the joints, but I was wondering if my modification would be an improvement. It would also mean that I could fill in the wear with weld, file it roughly round (snug fit to the driveshaft) and fasten with a setscrew. without the expense of a replacement flange, and/or drive shaft, if they could be found.

I am not a collector of these machines, though original would be nice. I am just looking for a reliable tractor.

Ron C.

#7 JDBrian OFFLINE  

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Posted September 10, 2011 - 07:19 AM

There is no problem with the motor mounts.

I guess I used a poor wording for my query. The couplings and shafts are totally engaged on both my units. I suspect that the length of the overlap, which is the full length of the fitting, is inadequate to support the shaft, when it must be free to operate as an expansion joint. I would trust the coupling if it were pinned.

Both units have the identical problem, which indicates a design deficiency to me.

Mind you, they are 30 years old, and I expect some wear in the joints, but I was wondering if my modification would be an improvement. It would also mean that I could fill in the wear with weld, file it roughly round (snug fit to the driveshaft) and fasten with a setscrew. without the expense of a replacement flange, and/or drive shaft, if they could be found.

I am not a collector of these machines, though original would be nice. I am just looking for a reliable tractor.

Ron C.

The parts are still available. I am familiar with the 314. I replaced the engine end coupler and repaired the one on the hydro end, but I ordered the parts to have in stock. At the transmission end the original equipment is a 1/4" pin through the coupling and shaft of the hydro. If you order a new coupler you get one that is threaded for 2 set screws. The set screws are pointed and larger than the diameter of the 1/4" pin. Obviously the hydro end is designed to have no play in it. On the engine end the shaft has a woodruff key and mine had worn the coupler badly. I replaced the coupler and built the shaft back up to round as you describe. The coupler is made of a sintered material from what I can see, and should be the part that wears the most. I found on my 314 the shaft was well engaged with the coupler and I did not have any concerns with the length of overlap. I agree that it is really a pretty crude design but it has lasted for many years on these tractors. I don't think there should be much front to back movement in the shaft as the mounts should hold the engine quite stationary in the x and y axis. I think the 317 had a U joint setup which would be an improvement.
Bad motor mounts do contribute to this problem. The mounts also tend to sag over time. The front ones are much thicker and I think this is due to the extra stress put on them by the PTO belt tension. The mounts can sag with age or fatigue. They can look fine from the top but be cracked underneath. This creates a misalignment between the drive shaft disc and the engine side coupler, because the back or front of the engine is lower than spec. This is easy to see by backing off the bolts on the coupler and seeing if a gap opens up when the bolt is at the top or bottom. I had to shim the front of the engine up a bit to get a good alignment when I replaced the rear mounts in mine.
If there is an alignment problem, there will be more vibration in the shaft and that will result in more wear. This is probably the major drive train issue for these old JD's.
Good luck with sorting out a solution. I would not cut the shaft in the middle though. That will create a shaft that wants to wallow in the center as it turns at high speed. Any imbalance you create in the shaft will become a much larger force when it is turning and create a potential wear area. The best place for any slip fit is on the end where the shaft is relatively firmly held in place. Let us know what you decide to do because this is a common problem that many people are interested in.




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