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Discussion Starter #1
I was inspecting the drive shaft on my 50” mower mounted on a 4 wheel tractor and noticed the driveshaft yoke that mounts to the gearbox input shaft is a little wobbly on the splines. The bolt was in place and tight, and it runs quiet, but i’m thinking this is a problem.

I was thinking of building up the spline joint with a repair compound like loctite quick metal and replacing the ¼” bolt. Is this in line with what other people have seen and done?
 

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Mine was beyond saving, it was to the point it would break the bolt if the mower went down into a dip and the angle changed. I ended up replacing the entire lower section of the shaft with a Precision yoke, it was split longways and had 2 5/16" bolts to pinch it to the spline shaft. Only downside is it uses a bigger U-joint, so I had to replace the female side of the slip yoke as well.
 

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Discussion Starter #5
I appreciate the responses, mine still works fine, will have to disassemble it to see just how loose it really is.
 

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Discussion Starter #6
I will provide follow-up here to close out this old thread. I have been working on the deck where time permitted as I won’t need it until spring. I replaced the U-joint in line with the recent thread on the subject, the part was a Gravely 012134P1 which crossed to a NEAPCO or SPICER 1-0170. It went OK, but I had the same issues others had seen with the yoke bending a bit. I was able to get past that problem by using all thread and two nuts and washers to spread the yoke after it was apart. I also had one U-joint cap that was spinning in the yoke, Problem there was no grease fitting on that end. I assembled the joint with Loctite 609, should take care of the loose fit. The splines were not bad, but the holes in the yoke were badly worn. I decided to enlarge the hole to 5/16” from ¼” to fix the problem and found the splined input shaft was unbelievably hard metal. I was able to get the hole enlarged by using a cobalt burr to remove the splines slightly at the opening and then a carbide bit to make the hole. A normal high speed steel bit would not even touch the shaft, but worked fine for the yoke. I made a body fit bolt out of an extra-long standard 5/16” bolt with the threads cut down to have full diameter in both sides of the yoke. I assembled the splines with Loctite 660 (Quick Metal) just to take up any slop in the splines.

The previous suggestion to tap the yoke holes and install set screws was very elegant, but my holes were out of round, and even would have been oversize for 5/16-18 screws.
 

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Resplining a yoke is tricky. It is hard to chuck it on a lathe.
 
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