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CC 128 K301A crankshaft trouble


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Hello, 

   I'm new to Cadets but work on my Father in laws Cub and I have a TD-62 so you could say I kinda like Internationals. my problem is my new to me Cadet 128 spit a front PTO bolt and upon disassembly among other things I found that someone in its past had welded the crankshaft key in place on the crank. After some grinding and a few whacks with a chisel   I found that the key-way is all torn out on the welded side. to be fair some of it could have been from chiseling the weld off, but the weld is there for some reason so? it looks like a rebuild will be in order anyway so I was thinking of replacing the crankshaft unless it can be economically be repaired, of which I have no idea, and if it must be replaced the question is do I need a K301A crank specifically from a cadet or can I use any K301A crank with a 1" PTO shaft? any help will definitely be appreciated.

 

Thanks

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As J-mech confirmed a couple days ago, K-series crankshafts are cast iron. Tough to weld a steel drive key to a cast iron crankshaft. The starter/generator pulley engages that key that wallowed out the keyway, and the drive cup on the pulley drives the PTO clutch. There's no keyway and key between the PTO clutch and crankshaft. Every time I've had the starter/generator pulley off I've tack welded the pulley to the hub the keyway is in,  every one I've had has come loose, easier to weld before it comes loose.  And when you replace the key, put a long piece in, inch and a half, two inches, spread the stress out more keeps the keyway from wallowing out.

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I wish I had taken pics, but the key itself was welded into the key-way and I was able to pull the hub/pulley off once I ground a piece of weld off that was in front of it. thats when I found out that the key was welded in on one side which i cut with a Dremel tool and chiseled out. I wasn't intending to take the pulley off at all but found the PTO bearing to be rough and dragging so after I got that off and found the weld bead in front of the pulley I had to take it off to find out what was going on there. In retrospect I should probably have let it as is as it was doing fine until the PTO spit the screw.

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Yeah, you should have just left it alone.

 

No reason to replace the crank.  Cut a new keyway 90 deg from the first one.  A lot of work to do.  Pretty much have to tear the whole engine down to get it fixed.  Might consider an overhaul.  I'd be looking at all options before tearing it down if the engine is in good shape.  

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J-Mech,

      Yep,  hindsight and all that, As far as the shape of the engine goes it runs and I've cut some grass with it, that being said the whole machine has been sorely neglected, i.e. missing parts frozen spindles on the mower deck and just general neglect. I have been able to rectify a lot of the neglect with healthy doses of grease and spray lube but since I don't know how long it's been run without a clutch pedal return spring and various other parts of differing importance I was planning on doing a bit of work on it anyway, just not overhauling the engine quite yet, and after reading your breakdown of DIY rebuilders in another post I am seriously thinking of having that part done buy somebody more competent and who possesses the right tools to do it right. That breakdown was pretty spot on and I recognize myself in the lower 50% not because of internet overconfidence but mostly time, money, and and a lack of resources not to mention a little good old American can do, but probably shouldn't.

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The transmission clutch throw-out bearing is a rather high maintenance wear part mostly due to slipping the clutch to control tractor speed when trimming with the mower. I think MidWest SuperCub still has some T/O bearings made by IH's original supplier. They bought Thousands! Yep, had to keep the clutch and brake in adjustment and keep a usable return spring on the pedal because if the clutch lever rubs the bearing you're using up unnecessary bearing life. If your tractor is a daily work tractor stick with OEM clutch parts!  I put a RED die spring in my #72 when I put my hot-rodded K321 in it,  still have the throw-out bearing that failed in less than a year,  quite impressive failure actually.  It has ALL brand new OEM clutch parts now.

The guys on IH Cub Cadet . Com argue frequently about whether gear drive or hydro's are better. It depends on what your doing. Pushing or blowing snow with frequent direction changes is a hydro job. High draft loads like moldboard plowing is a gear drive job.  I have two gear driver's, my 72 I bought used in 1981, and the 1965 #70 Dad traded an Original for in 1965.  I have a 982 I bought in 1999 and my 2015 CC TANK zero turn. Had a 129 I restored from little more than a basket Case starting in 1989 or '90.

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1 hour ago, DOCTOR EVIL said:

The transmission clutch throw-out bearing is a rather high maintenance wear part mostly due to slipping the clutch to control tractor speed when trimming with the mower.

I don't think this is true.  I've got over 20 Cub Cadets.  I still have the 71 that grandad bought new.  (Cool that you have your dad's 70 he got new!)  I've never put a clutch in it, snd don't know it it's ever had one.  It's on engine number 3, ready for 4.  It survived dad and I both as kids.  All my other gear drive tractors came to me with original parts on the clutch too.  The clutch and components on a Cub Cadet are some of the most durable clutches of all GT's, requiring only the occasional adjustment and greasing the T/O bearing now and again.   I agree with the rest of what you said, but the CC clutch isn't a "high maintenance wear part".

 

You can still buy the original T/O bearings from CCC.  Pricey, but available and well worth the money.  MWSC's kevlar clutch is also a good upgrade.  I do not recommend a heavier clutch spring unless you pull a moldboard plow a lot, or are doing work to the engine.  Make sure to replace the teaser spring.  Most all are broken upon disassembly.   You don't need the anti-rattle springs, so if they give you fits toss them. Replace the driveshaft centering bearing in the trans yoke, and engine coupler.  Check the driveshaft for wear. If the holes in the shaft are worn, ends where the bearings are, or the area where the T/O rides, the shaft is junk.  There is a guy in PA who builds new ones.  PM me if you want his info.  Very reasonable prices.  He makes several NLA driveshaft parts. 

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8 minutes ago, J-Mech said:

I don't think this is true.  I've got over 20 Cub Cadets.  I still have the 71 that grandad bought new.  (Cool that you have your dad's 70 he got new!)  I've never put a clutch in it, snd don't know it it's ever had one.  It's on engine number 3, ready for 4.  It survived dad and I both as kids.  All my other gear drive tractors came to me with original parts on the clutch too.  The clutch and components on a Cub Cadet are some of the most durable clutches of all GT's, requiring only the occasional adjustment and greasing the T/O bearing now and again.   I agree with the rest of what you said, but the CC clutch isn't a "high maintenance wear part".

 

You can still buy the original T/O bearings from CCC.  Pricey, but available and well worth the money.  MWSC's kevlar clutch is also a good upgrade.  I do not recommend a heavier clutch spring unless you pull a moldboard plow a lot, or are doing work to the engine.  Make sure to replace the teaser spring.  Most all are broken upon disassembly.   You don't need the anti-rattle springs, so if they give you fits toss them. Replace the driveshaft centering bearing in the trans yoke, and engine coupler.  Check the driveshaft for wear. If the holes in the shaft are worn, ends where the bearings are, or the area where the T/O rides, the shaft is junk.  There is a guy in PA who builds new ones.  PM me if you want his info.  Very reasonable prices.  He makes several NLA driveshaft parts. 

Thanks, I appreciate the help. this cub is going to be mostly for mowing and hauling brush around the yard so I wasn't going to hot rod it, just get it back to good working order so it will last and not unnecessarily eat parts. The way I figure it I can pay roughly $1000 for a box store mower or put money into a mower that will probably outlast me if I do it right and is in the scope of my mechanical abilities. 

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  • 5 weeks later...

I don’t like welds on cast iron. I’d  go to a machine shop and have a Rockwell test done in that area. I may not be ductile enough to use. 

I would not use that shaft at all for pulling ? 

Kohler cranks are not that good a quality , to horror story’s of pullers overreving them , and flywheels the same thing. 

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On 8/5/2019 at 7:08 PM, 560Dennis said:

Kohler cranks are not that good a quality , to horror story’s of pullers overreving them , and flywheels the same thing. 

The quality is fine for what they were made for.  They WERE NOT made for over 4000 RPM.  

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6 hours ago, J-Mech said:

The quality is fine for what they were made for.  They WERE NOT made for over 4000 RPM.  

How can you be sure about that welded crank ?

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3 hours ago, 560Dennis said:
9 hours ago, J-Mech said:

How can you be sure about that welded crank ?

All that was done was put weld on the key up on the crank nose.  He says he knocked most of it off with a chisel, so it was crappy weld anyway.   Secondly, the nose is solid, so you can weld on it without much risk.  I'm sure it never got hot enough to damage it.  They weren't hardened on the nose, so a Rockwell test wouldn't do any good.  If the nose was hard, they wouldn't eat keyway's out of them like they do.  

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5 hours ago, J-Mech said:

All that was done was put weld on the key up on the crank nose.  He says he knocked most of it off with a chisel, so it was crappy weld anyway.   Secondly, the nose is solid, so you can weld on it without much risk.  I'm sure it never got hot enough to damage it.  They weren't hardened on the nose, so a Rockwell test wouldn't do any good.  If the nose was hard, they wouldn't eat keyway's out of them like they do.  

With a sharp corner on the key it’s a stress riser , with weld the then the shaft had to change form nodular all along weld , cracks will result. 

 

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7 hours ago, 560Dennis said:

With a sharp corner on the key it’s a stress riser , with weld the then the shaft had to change form nodular all along weld , cracks will result. 

 

Nah.  Seen too many of those cranks with weld on the nose from guys who didn't know any better trying to fix them.  Never caused any issues.  Not a lot of stress on it to run a PTO.  He can still just move over 90° and cut a new key and he'll be good as new.

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J-Mech I would have to agree with you. I think before I got so far as pulling the crank to cut a key way I would try some JB weld or something similar. What have you got to lose when you think about it. You can always go the new key way route if needed. Anyway just a thought.

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7 hours ago, IHC_1470 said:

J-Mech I would have to agree with you. I think before I got so far as pulling the crank to cut a key way I would try some JB weld or something similar. What have you got to lose when you think about it. You can always go the new key way route if needed. Anyway just a thought.

Seen that done too.  Doesn't hold very long.  Only one solution.  Sorry, just how it is. Doesn't take long to tear down that motor. 

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been busy lately, sorry for the long absence, I agree with J-Mech, we use a product called duraloy at work and while we use it for non load bearing surfaces I have noticed that the mix is very critical and that even when done well it still fails occasionally and I believe this is made more for the type of application you guys are talking about ( keyway repair) and I have resigned myself to a rebuild and crank keyway recut any way.

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