LX5 cutter shear bolt

   / LX5 cutter shear bolt #1  

FordTruckGuy

Bronze Member
Joined
Mar 26, 2005
Messages
52
Location
Richmond, VA
Tractor
Deere 790 MFWD
Broke the shear bolt yesterday cutting down some brush in the woods. Noticed the drive line off the PTO was spinning, but not the blade. Checked, and sure enough. Was struck to see the bolt split in two, especially since it didn't seem as if I had accidentally gone over anything difficult, such as too-large stump or rock.

Has anybody else had this happen? Am I overusing the cutter?
 
   / LX5 cutter shear bolt #2  
On the 4x10 series, just starting can shear a bolt. If you are engaging the pto hard, it can be starting the break, so that it wouldn't take much to shear it completely while in real use...
 
   / LX5 cutter shear bolt #3  
I have the 513, the ealier version of the LX5, I believe. I go through bolts alot, but a key thing is to engage the PTO at idle, and slowly move the throttle up to the rated PTO cutting RPMs
 
   / LX5 cutter shear bolt #4  
I'm not sure what size of tractor you are running the LX5 on, but I can tell you that I finally decided the LX wasn't enough for my 4320. I always engaged at lower RPMs, but still blew through bolt after bolt on silly things like scalping a high spot of dirt in the field. I moved on to an MX6 and I couldn't be happier.

Don't get me wrong, the LX series has its place. I had a LX4 on a 2210 and it worked perfect. I know you can get a slip clutch on the LX, but I like the weight of the MX (doesn't bounce around like the LX), and the cut is superior.
 
   / LX5 cutter shear bolt #5  
Agreed---I also blow bolts in the most unusual places and generally in conditions where there should be no trouble. This winter I plan to get whatever I can for my 513 in trade or sale, and get an MX6, which should be the upper end of what my 990 can handle. If that's recommended against, I know I can handle the MX5.

I always wanted to learn how to maintain a slipclutch...
 
   / LX5 cutter shear bolt #6  
I had a LX4 on my 2210 and now I have a MX6 on my 4720. The MX6 is a lot tougher - in a big way. I have been mowing over some serious stuff and it just asks for more.

I am to the point I think everything should have a slip clutch!

D.
 
   / LX5 cutter shear bolt #7  
I've only sheared the bolt on my LX4 once, after several hours' use.

Hope you were able to find where the bolt goes. I posted on here, and no one told me what position on the shaft it was. Suspect it's like the LX4: near the gearbox at the back end of the casing that carries the rear U-joint.

I removed the U-joint to rotate it. Someone suggested moving the PTO selector to the both or front position (if you have it on the 790). This would allow it to be rotated without removing it.

I've since hit a couple rocks that probably shocked the bolt as much as the relatively small piece of brush that broke it the first time. The bolt held.

Oh, I cut back the plastic shield over the rear U-joint to better access the bolt. Afterwards, I found out how to get the shield loose to move it back: remove a little screw, rotate until the "C" and "D" positions on the plastic pieces line up, slide shield back. I like the shield cut back. Can see better that the shaft is rotating all the way to the gearbox.

I start my LX4 at about 1500 rpm. Lower will stall the engine in cold weather. Higher risks shearing the bolt.

Ralph
 
   / LX5 cutter shear bolt #8  
slip cluthes are the only way to go. the maintenance will take a half hour per spring if it is not used year round.
 
   / LX5 cutter shear bolt
  • Thread Starter
#9  
Replaced the shear bolt last night. I am somewhat new to the equipment, and it wasn't too bad. But what a pain the plastic shield. I will try to remove as you note, but even your comments read cryptic to me, C & D positions, and which "little screw." I'd rather remove it, but not sure if it fulfills a necessary, protective function.

Also, was reading the operating/service guide last night, and the frequency of lubrication required. Could not seem to understand the oil in the gearbox lubrication, which required removing a plug that just didn't seem removable.

You say that you engage the PTO at about 1500 RPM. Is this with the tractor in or out of gear, clutch in or out, etc.? Thanks.

Thanks.
 
   / LX5 cutter shear bolt #10  
Maybe there are different types of shields on these pto shafts, but on my old LX5, it was just a matter of turning the plastic shield until the tabs lined up, then sliding it back out of the way. No screws needed to be removed on mine.

It only takes a couple of minutes to change the bolt, its just a pain when you are in the middle of the field working and you don't have your tools and a spare bolt with you.
 
 
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