F3680 Center Blade Intermittent Problem

[1bush2hog]

I was out mowing this past weekend with my F3680 and noticed that the center blade was not cutting the same as the two side blades, especially when cutting thru some thicker/higher grass. I could hear the blade stop turning and definitely see the path of grass that was higher in the middle. I checked the belt, and although not really tight, it was in pretty good condition. The tensioner and spring appeared OK too. When checking the blades I noticed that the spindle for the center blade was hotter to the touch than the other two spindles. I didn't have tools with me at the time to check the tightness of the blade since the mower is at some property I own out of state.

I was in a hurry to finish mowing so I just ran over the missed areas twice and got everything cut. Was going to order some new blades, blade bolts, and a new belt. Since I purchased the machine with a little over 800 hours on it, I'm not sure how new the blades and belt are either.

After looking at the parts diagram online however, I'm wondering if maybe the spindle bearing could be the potential culprit here that's causing the 'slipping' of the blade.

Anyone had any similar experiences or had to change out a spindle bearing on one of these F series mowers? Would appreciate any comments, tips, tricks, etc.

Also, I would appreciate it if someone can tell me what size socket I'll need for the blade bolt - Maybe 30MM?

Thanks

Bruce

 

[kbuicker]

I was going to guess the bearing too. I had one completely destroy itself one time.. balls were hanging out of it (as gross as that sounds!)

 

[jcummins]

Check whether blade is tight...I've run into that a couple of times with a ZD326. Haven't encountered it with my F3680.

 

[JOHNTHOMAS]

Check whether blade is tight...I've run into that a couple of times with a ZD326. Haven't encountered it with my F3680.

I have encountered it with my F. I took the blade off, reseated it and tightened it down with air wrench and no problem since. There seems to be a close but not correct seating that feels tight by hand but it isn't tight enough to do the job. Try taking blade off and retightening before spending money. :2cents:

 

[1bush2hog]

I have encountered it with my F. I took the blade off, reseated it and tightened it down with air wrench and no problem since. There seems to be a close but not correct seating that feels tight by hand but it isn't tight enough to do the job. Try taking blade off and retightening before spending money. :2cents:

Hopefully that is the solution

I read in your post on changing blades that blade bolt is a 30mm bolt - Is that correct? Also how often do those cup washers need to be changed out?

 

[ProjectKing]

I have encountered it with my F. I took the blade off, reseated it and tightened it down with air wrench and no problem since. There seems to be a close but not correct seating that feels tight by hand but it isn't tight enough to do the job. Try taking blade off and retightening before spending money. :2cents:

This is good advice. Also make sure all mating surfaces are clean (no grass, no oil, etc).

Torque the spindle to blade bolt down to factory specs with a torque wrench. On my ZD326 it requires fairly high torque. Around 90 ft lbs I think. Check your manual.

A slipping blade will quickly damage parts so fix it before you mow.

 

[JOHNTHOMAS]

Hopefully that is the solution

I read in your post on changing blades that blade bolt is a 30mm bolt - Is that correct? Also how often do those cup washers need to be changed out?

Not sure of size. I did change the cup washers one time but I don't think it was needed. I think I just hadn't seated the blade correctly.

 

[1bush2hog]

Well I got the center blade tight but not sure that I don't have another issue. I tried tightening the blade but the spline and pto shaft would turn too even after trying to put in gear, leave in neutral, engage pto, and leave unengaged, and/or every combination thereof I think. Even with blades blocked with 6x6's the Shaft would continue to turn. I ended up putting a piece of rebar thru the universal joint on pto shaft so I could keep it from turning while I tightened blade bolt

So now I'm wondering if I may have a pto clutch/brake issue or something else or did I overlook something in process?

Any thoughts?

 

[ProjectKing]

Well I got the center blade tight but not sure that I don't have another issue. I tried tightening the blade but the spline and pto shaft would turn too even after trying to put in gear, leave in neutral, engage pto, and leave unengaged, and/or every combination thereof I think. Even with blades blocked with 6x6's the Shaft would continue to turn. I ended up putting a piece of rebar thru the universal joint on pto shaft so I could keep it from turning while I tightened blade bolt So now I'm wondering if I may have a pto clutch/brake issue or something else or did I overlook something in process? Any thoughts?

Sounds like the threads in the hole or on the bolt are crossed or damaged. This would explain why the spindle turns and why your blade is loose.

 

[1bush2hog]

Sounds like the threads in the hole or on the bolt are crossed or damaged. This would explain why the spindle turns and why your blade is loose.

Good thought but No cross threading of the blade bolt. Threads are perfect