Bush hog breaking shear pins

[Texasmark]

I would keep the weather off it also. Agree on the annual service as Lineman said. If you are wondering what's the right dimension on spring length, undo it like he said, get it slipping...shining up the rust, and tighten it somewhat....all springs same dimension. If you get into moderate vegetation and it slips tighten them all till it quits. If you get into heavy vegetation you have to make the decision to tighten till it quits, or don't take as big a bite or slow your ground speed in heavy stuff.

 

[Schrodinger]

Pretty much what "scribe a line" means.

Yea, just a helpful hint on easy things to use that can be wiped off. I suck at scribing.

 

[Menagerie-Manor]

Since as you say it's been beat on you might want to check and see if all the blades are reasonably matched.

 

[ericm979]

Shear bolt AND slip clutch? Usually it's one or the other. Is that how it came from the factory?

 

[DonRybak]

As ericm979 mentions, it's unusual to have both a shear bolt and a slip clutch. The shear bolt acts as protection for the gear box if you strike something with enough force to damage the gear box. The bolt shears rather that damage the gear box. The slip clutch serves the same purpose. The disks are supposed to slip when the designated force is applied. I would never replace a shear bolt with a higher grade bolt. What if the slip clutch is adjusted incorrectly to a much higher slip rating? If the clutch doesn't slip and the shear bolt doesn't shear then something in the gesrbox faces destruction. There are numerous youtube videos on how to properly adjust the slip clutch and it's possible that the disks are worn out and have been adjusted to depend on the shear bolt to protect the gear box. Your call but I would go the safe route and make things the way they should be.

 

[RickB]

As ericm979 mentions, it's unusual to have both a shear bolt and a slip clutch. The shear bolt acts as protection for the gear box if you strike something with enough force to damage the gear box. The bolt shears rather that damage the gear box. The slip clutch serves the same purpose. The disks are supposed to slip when the designated force is applied. I would never replace a shear bolt with a higher grade bolt. What if the slip clutch is adjusted incorrectly to a much higher slip rating? If the clutch doesn't slip and the shear bolt doesn't shear then something in the gesrbox faces destruction. There are numerous youtube videos on how to properly adjust the slip clutch and it's possible that the disks are worn out and have been adjusted to depend on the shear bolt to protect the gear box. Your call but I would go the safe route and make things the way they should be.

As described in post #3.

 

[CoyPatton]

Which is exactly why I'm suggesting A) servicing the clutch. And B) identifying the correct spring length spec to use.

It is also very important that servicing the slip clutch allows for light pressure on the plates and the clutch. You want to dress all contact surfaces.
Next important issue is proper tension on the springs when servicing. Too tight and you risk damage, too loose and the cutter is useless, as the clutch constantly slips. The marks are very good suggestion as you want to be sure it is slipping during service. And it should be done at least yearly.
Your description almost sounds as though someone wanted the slip clutch defeated and to use a shear pin. Unfortunately it generally works about like your experience.

 

[Cougsfan]

I know of a case where the slip clutch was adjusted too loose and was constantly slipping, overheated drastically enough to catch some flying grass on fire and burn a field down. I agree with the grade 8 bolt and checking out the slip clutch as needed. When done and you start using it, stop after a while to check that the clutch isn't getting hot.

 

[Jason280]

Thanks for the suggestions, I'll pull the slip clutch apart this weekend and see if it makes a difference.