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1512D Spiral pin on driveshaft keeps fallling out. What should I do?

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Well-known member
Jul 2, 2007
Stephen Galante
For about the 5th time in the last 6 years or so, the spiral pin (I hope that is the correct term) on the front end of the drive shaft fell out again on my 1512D. Replacing it at the dealer isn't a gigantic expense since they normally charge the $1 for the pin and 1/2 hour labor to get to it. My problem is without that pin, as you know, the hydraulics lifting and driving don't work, so wherever the tractor is, I have to find some way of getting it to and onto the trailer to bring it in. I have tried temporarily replacing it myself with a temporary screw or bolt, but never can get those holes lined up to get it in.
According to the repair shop, the hole has gotten ovalized which causes the pin to come out easier.

Yesterday, while cutting grass, the machine started to shake when the idle was turned up to it's normal position, so I quickly pulled it into the garage, hoping to drive it up on the trailer this morning. No such luck, the hydraulics stopped working, and I also noticed a small puddle of Hy-Tran on the floor. I am sure that is more trouble also.

Here is my question. I know the best solution would probably be to go the route of the infamous CV drive shaft conversion. I don't have the resources (i.e. the machines or mechanical knowledge) to do that. I even asked the service guy on the phone, who always works on my machine about it and he wasn't familiar with how that would be done. I had told him there was some magical way of doing it with the driveshaft from an 1862 (I think that was what I read). He asked if I saw it somewhere, as to how the driveshaft connects to the transmission itself? This mechanic is great, the dealership he works at is a Cub Cadet and Kubota dealer where he has worked on everything in his 20+ years there.
I guess my post comes down to a few questions.
1. Is there anyone out there that I can have machine the parts so I can get them to him to make this changeover, who can also give me proper detailed installation instructions, since to pay the dealer $85/hour to do the machining and such is out of my price range (not saying someones time isn't worth decent money, but I thought maybe someone who doesn't have a dealers overhead might be able to machine the parts less expensively.)

2. If I don't go the way of a CV driveshaft, what is the thought of replacing the spiral pin with a grade 8 bolt and lock nut? The mechanic thinks the grade 8 bolt may be too brittle and may break off easier than the spiral pin will fall out.

Thank you in advance for your ideas.
Stephen, David Kirk recently posted on the main forum about his 1250 throwing the spirol pin from the drive shaft. He posted his solution HERE His post is about 3/4 of the way down the page.
Thank you for that link. I really would love to fix it for good, but that is definitely a more economical solution.
I would still love to find out if anyone is capable or willing to machine the parts to do the CV fix at a reasonable cost.
I am out of work right now, so your solution may be the best for now. If I am working by winter, it would be a great time to leave my 1512D at the dealer and have him install the CV shaft if I can get it.
In our much higher HP pullers, we use 1/4-20 bolts and locknuts, grade 8 of course. These are very reliable so in your app you should have no problem. Just don't crank down on the bolt, snug it securely and don't overtorque it.
Another fix, using the spirol pin, is to "safety wire" it in place, feeding a wire through the pin and pulling the wires together on one side of the coupler, twisting it securely
If you don't want to safety wire it like Dave suggested in the link, you can replace it, then wrap a stainless steel hose clamp over the coupling and tighten it up good and snug...worked on my 149 for many years.....
I had a similar problem on my 1512 and putting the wire seemed to take care of it. Now I wire all my spiral pins.
I know a guy that is building the CV conversion for these as a bolt in. E-mail me, I'll try to dig up his contact info.
I built my own, and yes, it is pretty involved to build your own.
Rich Beem, I sent you an email this morning, let me know if you didn't get it. Thank you again.
Just replied,
Had to loan my daughter my laptop...she did not charge hers.....kids.
Here are my "only intended for me to understand" notes on the CV conversion.
This style uses an existing bore on the Kubota output for centering (56mm). I've seen some guys rely on only bolts or flat head screws...I do not trust that.
The drive shaft length is always the wildcard in the equation, and is best established after the CV adapters are mocked up on the tractor. Measure between the faces and then ad the proper spline engagement for the CV's = overall shaft length.
I had the spline engagement established on the workbench while cleaning up the used parts.

For your entertainment and eternal confusion:

Here is the engine CV side adapter attached to the Kubota output.
Having the engine apart last winter had some benefits, as getting good measurement is pretty tough in the chassis.

Thank you for the diagram and instructions. I have been in contact with the guy who builds these replacement parts down (I'm in Western NY) in Pennsylvania and another Cub Cadet guy whoa also done this conversion. It seems like everyone knows everyone, whether they are on this forum or on the other big forum.
Waiting to hear from my mechanic on exactly what is wrong. I have been told by someone else in the know, that if I need to go for a new pump (not sure if that is needed yet), I should replace it with one off an 1863 or perhaps an 1864 (I forgot which one) due to the fact that it uses a splined shaft which is better to start out with if I go through with the conversion.
I only wish I could find someone closer to NY that has done this conversion that would be willing to do it over the fall/winter. I had one person offer, but they are in VA near the NC border. Any offers????
I found that the pump from an 1863 was not a direct swap due to the output gear being a different gear pitch.
So, easiest way to gain the splined input is a complete rear end swap. Which is not very hard, and is a good time for degreasing...replacing seals and fuel lines, and flushing that dirty old diesel tank.
What I did was a pump rebuild with a combination of parts from 1512 / 1863. ** This is not easy**
Rick, the 1863 uses a Hydro-Gear pump. Do you mean to use one from an 1864? Some of the 1541's use the CV system also.
*Disclaimer* I was told that it was from an 1863, but I just looked at the parts look up and that is different indeed.
So, I'm not sure what pump I started with. It is the same as my 1512 pump, but had output for PTO on the top shaft.
The pinion output shaft had a different pitch gear. Otherwise identical parts.
Drive shaft was pretty much junk when I bought my 782D.
After finding all the parts to make the engine right. I decided to put in a CV drive shaft instead for buying new discs. Since it has the old style pin in the trans output; I stayed with what I had. Just a spiral pin and a safety wire. Been five years now no problems.
It's been almost 38 years ago when my old boss sold me a used and abused Cadet 100.
After a few weeks of mowing, the driveshaft rollpin failed. I drilled out the hole a bit and installed an aircraft "AN" bolt and locknut. That lasted about 8 months before it was bitten in half. Then I came across a type of roll pin made by Spirol. It wasn't the normal hardware store "C" shaped pin, but was actually a hard rolled metal type. I beveled one end to facilitate installation, then with difficulty, drove it in. And it's been in place ever since! It worked so well that I got a larger size for the steering arm on the right spindle.
I'll vote for the safety wire. Never seen one fail that way.

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