Burned up Universal joint on PTO shaft

[jpaeye]

Was out the other day blowing leaves with my TC33D and Goosen blower when I smelled something burning. Looked behind me to see smoke. Shut down the PTO and examined it. Burned up the u-joint closest to tractor. Hot enough that the paint on the yoke discolored and the cups of the u-joint were essentially welded into position. It also had some metal rubbed off the yoke at one of the pins.

Spent all Saturday morning running around to find parts to fix it to no avail. Finally ordered a new, complete Eurocardan shaft assembly from Agrisupply and have received it in 3 days.

What a Rubic's cube the safety shield is on this thing. I realize now my old one which I purchased used with the tractor probably wasn't all that safe. Took a few minutes to figure out how to get the new one apart. Directions were only minimally helpful. Now to get to cutting it to length tomorrow night. Any suggestions on making assembly and disassembly of these things easier?

Question I have for everyone is what do you think made this u-joint disintegrate. It was only year old, and gets greased every time I use it, approximately every 4-8 hours. Only mistake I made is I did not use my red EP grease, I used Lucas Extra heavy duty grease this last time. Could that have been the culprit? Sure do hope I won't have to be replacing U-joints every year or buying new PTO shafts (I did buy an extra just in case since it seems the equipment always breaks when needed most). The angle is at about 10 degrees.

Leaves sure have piled up without use of the blower.

 

[Hooked_on_HP]

Is there a chance the pto shaft was to long. Did the 2 halves of the pto shaft slide together easily. Were the ujoints phased properly(inline). These are the main things that cause ujoint failure.
Bill

 

[jpaeye]

No, the shaft length was appropriate and phasing good. I may be near the limits of my angle.

Hopefully will het out tonight to cut the new one and then reassemble the rubics cube.

 

[john_bud]

Are you sure it was the u-joint? It sounds like there was a slip clutch that was adjusted too loose.

 

[MHarryE]

Eurocardan has an online catalog that can give you a general idea of what the angle will do to life. Looking at an example they have, a shaft assembly running straight has over 2,000 hours life but at that same torque and speed and now with 6 degrees of misalignment it drops to 320 hours. I did some rough measuring on their nomogram and driveshaft life drops to about 200 hours at 10 degrees. It is possible that your drive has too much angularity for good life. I was going to say that ipI didn't visualize 10 degrees as being a very large misalignment but the nomogram was enlightening. I think a sadist dreamed up the shielding, and Eurocardan isn't the only tough one. I fought trying to install a new shield on a driveshaft for a long time, then gave up, came in and Googled it. Somebody figured out part of the assembly that wasn't described well in the instructions so I was able to get it. The Eurocardan shield on my finish mower often falls apart so I have got pretty good at reassembling it, but I have not yet determined the right amount of duct tape to use to make a permanent fix.

 

[RickB]

No, the shaft length was appropriate and phasing good. I may be near the limits of my angle.

Or beyond the limit.

 

[nspec]

I would say if the angle is in fact 10 degrees, that it is too much for continuous duty operation. If it's only a leaf blower, shift the hitch arms over more or lower the hitch if you can so you run the shaft as straight as possible. 3-6 degrees is the limit for continuous duty operation. (Ask me how I know!)

 

[LD1]

Without looking up the specs of the two greases it is possible that they werent compatible. There ARE some grease bases that dont mix well. I dont remember what they are but you can google it and read for days on end.

Or it could have just been a bum joint from the get go. The same joints get used in cars and trucks spin 3-4x's the RPM. 540 tractor PTO RPM isnt really fast.

Also, perhaps post a pic of you running/operating set-up and angles?

 

[SPYDERLK]

Was out the other day blowing leaves with my TC33D and Goosen blower when I smelled something burning. Looked behind me to see smoke. Shut down the PTO and examined it. Burned up the u-joint closest to tractor. Hot enough that the paint on the yoke discolored and the cups of the u-joint were essentially welded into position. It also had some metal rubbed off the yoke at one of the pins.

Spent all Saturday morning running around to find parts to fix it to no avail. Finally ordered a new, complete Eurocardan shaft assembly from Agrisupply and have received it in 3 days.

Question I have for everyone is what do you think made this u-joint disintegrate. It was only year old, and gets greased every time I use it, approximately every 4-8 hours. Only mistake I made is I did not use my red EP grease, I used Lucas Extra heavy duty grease this last time. Could that have been the culprit? Sure do hope I won't have to be replacing U-joints every year or buying new PTO shafts (I did buy an extra just in case since it seems the equipment always breaks when needed most). The angle is at about 10 degrees.

Does the old shaft have needle bearing cups in the u joints? Some light duty shafts have plain cups and will fail pretty quick if you come anywhere near their design limit for a substantial time. Thats the only thing I can think of since you where greasing plenty ... other than a faulty assembly.
larry

 

[jpaeye]

Thanks guys for all the replies. Getting the half shaft off the blower turned out to be quite a challenge. Actually split my forehead open applying a little "extra persuasion." Had to get four stitches to close it and still didn't get it off. Went back out tonight with a bigger pry bar and finally removed it with that and a sledge. This half shaft is a 1" shaft with key way, and the keyway was stuck. Burrs were present in the valley, making it impossible to remove. I will be filing that keyway to get it smooth again. A six spline yoke would be so much easier.

Hopefully will have it back together tomorrow night.

Interesting info on the angles and life of the u-joints.