drive shaft bolts

Thu Jul 25, 2013 2:08 am

My cub started breaking or wearing the drive shaft bolts for no reason i can find. just replaced the rear bolt with the hard bolt i got from hamilton bobs and after mowing 2 acres of grass the bolt is worn almost half into. any sugestions?

Re: drive shaft bolts

Thu Jul 25, 2013 11:23 am

I can't answer your question, but would suggest calling HamiltonBob's back and asking them.


Re: drive shaft bolts

Thu Jul 25, 2013 11:31 am

Check the alignment of the transmission to the engine. The rearends of the numbered series have a bad habit of working themselves loose, which will elongate the holes in the frame, allows for the alignment to become skewed, and then eat up the shaft bolts.

Re: drive shaft bolts

Thu Jul 25, 2013 5:04 pm

thanks for your comeback! all the bolts to frame are tight and haven;t moved as best i can see, except the two mounting bolts and spacers on the underside of transmission. one was missing the spacer and had a few washers in its place, but not enough to fill the gap. the one with the spacer was not drawn up tight. what would be the best way to check and adjust the alignment?
i've had this cub for six years and never broke a bolt until this year, and have broken or replaced six so far this season! the reasoning behind the alignment being the problem seems to fit what's going on! thanks

Re: drive shaft bolts

Fri Jul 26, 2013 6:28 am

Something is definitely not right. Check with Hamilton Bob for the correct spacers. Also check to make sure that the engine has not worked loose in the frame. I've never seen it happen but that doesn't mean it couldn't. Double check those rear bolts for the frame to transmission. They are actually known for breaking out those bolt holes. There's no way to actually "align" things, just make sure that all the bolts are tight and in the right places with the correct spacers.

Re: drive shaft bolts

Fri Jul 26, 2013 6:34 am

There is probably an easier way to do this than I am proposing, but this is how I did it.
Remove driveshaft. Insert a laser pointer into the pilot bearing (in flywheel). If the laser pointer is too small, roll electrical tape around it to make it the right diameter to fit snugly.
Rotate laser pointer. It will draw a circle on the transmission. The center of the circle is the alignment center.

Re: drive shaft bolts

Fri Jul 26, 2013 8:20 am

Which tractor do you have?

By "rear bolt" you mean the bolt on the driven disc of a 154/185?

If so, I don't think the alignment would affect that bolt. Poor alignment can cause the spider spring on the disc to break but I don't see how alignment would affect the rear bolt. A worn input shaft on the transmission or a worn hub on the driven disc can let the disc wobble and that will wear the bolt. The disc should fit tight on the shaft with really no wobble without the bolt installed. Put in neutral, press the clutch pedal and spin the driven disc by hand, if it wobbles side to side or front to back then the disc or input shaft is worn. The bolt also has to be very tight or the driven disc will wobble and wear the bolt.

I expect your disc hub and input shaft are worn or the replacement bolt was not tight enough.

Re: drive shaft bolts

Fri Jul 26, 2013 10:35 am

If the two mounting bolts on the bottom of the transmission were not properly installed, then this will cause some issues with the transmission moving within the frame rails. If the transmission is allowed to move, it will put pressure on the shaft, pressure plate, front hub, and the bolt.
The shaft should be tight within the pressure plate at the rear and hub at the front (no slop), and the bolt should keep things tight. If the shaft is not tight within the pressure plate or hub due to wear it'll eat the bolt up, especially as the transmission may be moving around within the frame rails.
Install the proper spacers on the bottom of the transmission and tighten things down, check for wear/slop at the pressure plate and input shaft.
You can check the alignment with a laser pointer as mentioned above. But with everything installed, it's probably not possible right now. With the tunnel cover removed, use a measuring tape to check the shaft against the frame rails where they are parallel front to back, left and right, and in elevation. Use a straight edge against the frame for any elevation changes. You can measure the shaft up at an angle to the frame as well.

Re: drive shaft bolts

Fri Jul 26, 2013 12:23 pm

Thanks a bunch to you all! this gives me plenty to check!

Re: drive shaft bolts

Wed Aug 07, 2013 5:29 pm

replaced spacer on bottom of transmission,the one that only had a couple of washers on it, and i had ordered a set so i removed the existing spacer so i could see if it was the proper one and found it was but the hole through had been worn oblong also allowing movement. then i started checking the flywheel and found it to be wobling. removed both shaft bolts and spun drive shaft and flywheel seemed to set straight. slid shaft forward along with engine enough to check fit of flywheel to trans shaft, loose as heck, floppy loose. replaced flywheel with new one, put every thing together again with new pilot bushing. nothing wobling. looks good and sounds good. also checked all bolts to frame found two that was a half a turn loose but showed no signs of movement.
with all the things you fellows gave me to check and all the things i found i'm very hopeful this has fixed my problem.
I want to thank all of you for your help. Now to fix my steering box so it doesn't shove the top bearing up out of place when i drive along something with my let front tire. anyone have this problem?

Re: drive shaft bolts

Wed Aug 07, 2013 9:56 pm

Rkuda wrote: .... Now to fix my steering box so it doesn't shove the top bearing up out of place when i drive along something with my let front tire. anyone have this problem?

I'm not sure I'm following you with this one. Is it the gear box that causing you issues, or the spindle?

Re: drive shaft bolts

Thu Aug 08, 2013 11:25 am

inside my gearbox. i replaced the bearings and cups and refilled it with grease. everything worked well until i crossed a small ditch at an angle, when the left front wheel got to the side of the bank it pull the steering all the way to the left without turning the steering wheel causing it to shove the top bearing up inside the tube and now you can turn the steering wheel a turn or so before it starts to move the steering components and the steering shaft travels up and down in the tube. i don;t know what is in the box to hold the bearing cuo and bearing in position but it only worked when there was no stress on things.

Re: drive shaft bolts

Thu Aug 08, 2013 6:48 pm

Can you pull the steering wheel up and down through the column? Did you pull the upper race when you changed the bearings? If so, it may not have seated all the way until you jarred the front end. Try to take the slack out of the worm shaft by tightening the cap on the bottom of the gear box.

I doubt it shoved the upper bearing up inside the tube. That can't happen without the upper casing of the gearbox being broken off.

Re: drive shaft bolts

Fri Aug 09, 2013 11:58 am

that seem to answer some of my questions! i thought the steering wheel touched the top of the tube when installed properly, that means if the bearing cup was not seated completely the shaft would not protrude far enough above the tube to install the steering wheel. when i bought this tractor it was in the same condition for steering as it is today. i removed steering shaft and all pieces of the bearings and grease. reinstalled with new cups and bearings worked great until the front wheel was turned sideways by the ditch. now im right back where i started. is there any space between the bottom of the steering wheel and the top of the tube when properly installed? would have to be in the neighborhood of 1 to 1 1/4 inches. thats about how far it moves up and down now?
was wondering what the top cup fit against to stop it from traveling up the tube and you answered that by stating it couldn't unless the top of case was broken off? what holds the tube to the case, is it just a tight fit or threaded. thanks

Re: drive shaft bolts

Fri Aug 09, 2013 5:00 pm

I went out and took a couple pics of mine.

You can see here the buldge just above the plug where the upper bearing race is. There is no room for the race to be forced into the tube, it would break the top of the gearbox off. The tube is press fit into the gearbox. I had to heat mine up to get it out to clean and staighten it out.

The steering wheel should be at or below the top of the tube when installed. There is a recess on the bottom of the steering wheel that the top of the tube is recessed in.

Are you sure the brackets holding the gearbox to the frame didn't break loose?