Kobuta L3600 Gst

[krickard]

I have a L-3600 Kobuta with 1200 Hrs and when had app.700 hours broke the drive shaft to front end drive, replaced then again at 1200 hours again the drive shaft pin on the coupling to front drive gave away and the spline was damaged to point of needing to be replaced, after the new shaft was replaced and new coupling installed,and with about 1 hour of use, this shaft broke clean at coupling to the engine side of the shaft. the 2 former shafts did not show what caused the problems this new shaft has the look of being heated to blackened look at both ends, hardening process? At $70.00 a shaft and 1 hour of use need to find the problem Tractor used to carry round hay bales to cattle in field, parked in shed. Any one else have this problem??
ken

 

[RickB]

If the bales are carried on a front loader, look at the rear ballasting and overall balance of the tractor with a bale on it. there are many, many variables, but you could very well be overloading the front driveline by not having enough weight on the rear axle for it to provide the majority of the tractive effort as it is designed to do. Replace both couplers with the shaft, check the drop box output shaft and the front differential pinion shaft for twist/runout.

 

[krickard]

Should of mentioned the bale spike is on the rear, with wheel weights and the front loader would be empty, some times cleaning out the barn load would be carried to trailer or dumped in a dry stack for later removial.
All of the splines look good there doesn't appear to be wear except when the pin fails and the coupling shifts to the front then the shaft spins removing the splines. this last shaft pin didn't give away the shaft broke where the tempering discoloring line was. Dealier has the shaft at this time to see if the Kubota Co. would replace in warrenty,problay not since they required advance payment to order another. 70 bucks for less than a hour of use. Any one else have this problem what what corrected it. Thanks

 

[mopacman]

sounds like the weld broke between the yoke and the shaft. when the splines wear out it would cause the pin to brake. you should lube the splines to help keep them from wareing out. Larry

 

[krickard]

To complete the post and if there is a Question of what happened to the shaft, if the Dealier doesn't install it is not in warrenty. so if you do your own maintance, forget any Warrenty of the Unit. Now the shaft was brittle where the heat treatment was done lasted 1 hour and broke clean at the coupling end to the shaft with part of shaft still in coupling,
The replacement shaft $70.00 took about 5 minutes to install could of done it in a suit and not get grease or dirt on hands. The Kubota is for sale, will purchase a working tractor not a toy. and since no one else has had this problem been a waste of time to ask for help.
so long ken