Farmall Cub

Hi All,
using all of the extremely helpful information on this site, I recently replaced the pto and transmission spline shaft in my '52 cub. I got all new parts from TMtractor, including the PTO shaft, bearing and shield, collar, and shift lever. when this didn't fix the problem of the PTO not staying engaged, I split the tractor and replaced the spline shaft, front bearing, front bearing retainer (making sure to install it the right way) all the gaskets etc... the only part that I did not replace was the rear roller bearing for the spline shaft because the one in tractor seemed fine. Today, I hooked up the sickle bar mower and off I went. everything went smoothly but after about 10 or so times engaging/disengaging the PTO with the shift lever, it stopped wanting to engage. I had to use a tremendous amount of force to engage it, but once engaged it ran fine. The pilot bushing came installed in the new spline shaft, and there's no slop between the spline shaft and the PTO shaft. I'm assuming it must be something with the collar???? but it's all brand new parts....... why would it work fine for a while and then all of a sudden not want to engage.

Any ideas??

May just be that it is new and needs to be used to go in smoothly, The only other thing I can think of is the set screw on the collar, it could be too tight.
Boss

Thanks Boss,
I did think to check the set screw, and it's fine, I put locktite on it too when I installed it, so it shouldn't be going anywhere. I did consider that maybe it just needs to be used a little, but boy oh boy it took all of my might to engage it the last few times.....made me worry a little.

yankeeleeroy wrote:............. Today, I hooked up the sickle bar mower and off I went. everything went smoothly but after about 10 or so times engaging/disengaging the PTO with the shift lever, it stopped wanting to engage. I had to use a tremendous amount of force to engage it, but once engaged it ran fine. The pilot bushing came installed in the new spline shaft, and there's no slop between the spline shaft and the PTO shaft. I'm assuming it must be something with the collar???? but it's all brand new parts....... why would it work fine for a while and then all of a sudden not want to engage.

Any ideas??

Sounds exactly what I experienced today with my sickle mower installed and used for the first time this year. PTO parts and shafts were all replaced a few years ago. Got the NEW belt on and adjusted tension. (It's NEW because when I took the sickle off last fall I put the OLD one some place safe, hopefully one day I'll find where that place is ) Anyway when I fired up after greasing and oiling everything and tried to engage the PTO it would go about half way and stop and I couldn't get it to go any farther. I backed off the tension on the belt and then got the PTO engaged. Didn't take it apart yet but I'm expecting that the bronze bushing in the end of the transmission shaft has wore through and pulling down on the pulley with the belt tesion lifts the inside end of the shaft enough to keep the collar from sliding onto the transmission shaft. Other option is that the small diameter end on the PTO shaft that goes into the transmission shaft is worn even smaller allowing the PTO shaft to raise up on that end and the collar not align. I like option one better.

A 2 cent reply....At times I have to ease the clutch out slowly, till about the 1/2 way point or so, then the PTO will engage with no grinding or problem....Are you trying that when you say it goes in hard or just relying on the lever and mechanical force...Dave

Thanks for the info Scrivet, the belt on the pully is pretty tight, maybe i should loosten it up. Pickerandsinger - i tried the old clutch trick, but that didn't work either, no matter what i have to push as hard as i can to engage the collar.

pickerandsinger wrote:A 2 cent reply....At times I have to ease the clutch out slowly, till about the 1/2 way point or so, then the PTO will engage with no grinding or problem....Are you trying that when you say it goes in hard or just relying on the lever and mechanical force...Dave

Good reminder, but as I understand yankeeleeroy's problem and definitely the one I had yesterday is a little beyond the normal two shafts not at the same "clock position" so the collar can slide forward onto the transmission shaft. With mine, engine off and manually working the PTO pulley and engagement lever still coldn't get it to engage. The lever would go about halfway and no farther. You could feel something hitting something else. The only thing I know of it could be was the PTO shaft and the end of the transmission shaft not being horizontally aligned (end to end). Only when I loosened up the sickle mower belt which would in theory drop the forward end of the PTO shaft would it engage. The only thing I don't understand is yankeeleeroy's is a fairly recent replacement for it to have wore out that quick.

Well Leroy, you got some good members interested....I'm sure Boss and Scrivet will be pondering this till it gets resolved....If I can think of anything I'll drop a line...

Scrivet, I think you are describing the exact problem i have.... i tried the engine off, manual turning the PTO while pulling on the engagement lever to get the the splines to line up, and i STILL Had to give it all my might. The collar goes about half way (right up until the splines on the spline shaft and the splines in the collar meet) and won't go any further, even though they are alligned.

You nailed it Scrivet, today I adjusted the belt tension, and now the PTO engages and disengages as smooth as could be. Thanks for all the help everybody!

OK bad bearing, bad shaft or bushing.

Scrivet, I'll put that one in my memory bank......Or whats left of it...

pickerandsinger wrote:Scrivet, I'll put that one in my memory bank......Or whats left of it...

I haven't tore into mine yet, waiting on bushing. You're welcome to fix it for me for the hands on lesson to reinforce your memory.

yankeeleeroy wrote:You nailed it Scrivet, today I adjusted the belt tension, and now the PTO engages and disengages as smooth as could be. Thanks for all the help everybody!

You've still got a problem.

As Boss Hog suggests, something is wore allowing the PTO shaft to "tilt" when there is too much tension on the belt.

That's either the pilot on the front end of the PTO shaft, or the bushing in the back end of the transmission shaft.

I was kinda thinkin pilot bushing myself but figured I'd leave it to the big guns...Did you replace it when you did the pto...I've heard of them falling out during the process.... Scrivet, I've done a couple of PTO rebuilds but no internal transmission work...So if its a PTO bushing you can send it to me and I'll hands on it.....If I could only remember my address......lol...Dave