Rotary Cutter Slip clutch not slipping at factory specs...

[Travis_R]

Bush Hog model 285.... EG/Comer slip clutch...

It isn't slipping at all. Never slipped since new and it's probably a couple years old. I loosened all the bolts on the clutch, turned the driveline by hand and the gearbox didn't turn, which tells me that it isn't froze up.

Re-tightened all the bolts to factory spec (1.26" / 32mm spring length) and it still isn't slipping! Killed the tractor 3 times the other day and I'm scared something's gonna break if I don't get it to slip.

This is my first and only implement I have that has a slip clutch.

What should I do? How many turns do I need to back off of each nut?

Thanks.

 

[Chilly807]

If the horsepower rating of your cutter isn't matched to your tractor, the clutch may not slip enough to prevent stalling or damage. In other words, if the cutter is rated for 50 HP, and you only have 30, it may not slip at factory settings.

You could try contacting Bush Hog and ask them for suggestions, the other alternative is to start loosening the bolts a half turn at a time and run it. See what happens.

I doubt mine's ever slipped either, but I've never stalled the tractor with it.

People here have suggested loosening the bolts until it is obviously slipping, then tighten them until it just stops. You don't want constant slippage or you'll wear the clutch out prematurely.

If you decide to loosen then re-tighten, mark the coupling first so you can see if it's moving. If it has moved under "normal cutting conditions" whatever those are :confused2:, then tighten a bit more. Check for heat after running for a few minutes, if the clutch is warm there's too much slip.

I'm probably going to go through this myself this year, I stripped the clutch down and cleaned everything last fall so I have a fresh start.

Again, try calling Bush Hog and see what they recommend first.

Sean

 

[Travis_R]

If the horsepower rating of your cutter isn't matched to your tractor, the clutch may not slip enough to prevent stalling or damage. In other words, if the cutter is rated for 50 HP, and you only have 30, it may not slip at factory settings.

You could try contacting Bush Hog and ask them for suggestions, the other alternative is to start loosening the bolts a half turn at a time and run it. See what happens.

I doubt mine's ever slipped either, but I've never stalled the tractor with it.

People here have suggested loosening the bolts until it is obviously slipping, then tighten them until it just stops. You don't want constant slippage or you'll wear the clutch out prematurely.

If you decide to loosen then re-tighten, mark the coupling first so you can see if it's moving. If it has moved under "normal cutting conditions" whatever those are :confused2:, then tighten a bit more. Check for heat after running for a few minutes, if the clutch is warm there's too much slip.

I'm probably going to go through this myself this year, I stripped the clutch down and cleaned everything last fall so I have a fresh start.

Again, try calling Bush Hog and see what they recommend first.

Sean

Thanks for that detailed reply!

The minimum hp required (Bush Hog's recommendation) is 30 PTO hp.... My tractor has 38 engine hp and 34 PTO hp.

 

[sweettractors]

Bush Hog model 285.... EG/Comer slip clutch...

It isn't slipping at all. Never slipped since new and it's probably a couple years old. I loosened all the bolts on the clutch, turned the driveline by hand and the gearbox didn't turn, which tells me that it isn't froze up.

Re-tightened all the bolts to factory spec (1.26" / 32mm spring length) and it still isn't slipping! Killed the tractor 3 times the other day and I'm scared something's gonna break if I don't get it to slip.

This is my first and only implement I have that has a slip clutch.

What should I do? How many turns do I need to back off of each nut?

Thanks.

Many farmers don't believe in "factory specs" for a slip clutch. How does the factory know what HP tractor is going to be attached to the implement and what type material is going to be mowed. These are variables that make it incumbent on the buyer/farmer to set the clutch to his tractor and for the material being mowed. Most of my customers back off a turn at a time until they get a slip when they feel comfortable with the adjustment? Ken Sweet

 

[Travis_R]

Many farmers don't believe in "factory specs" for a slip clutch. How does the factory know what HP tractor is going to be attached to the implement and what type material is going to be mowed. These are variables that make it incumbent on the buyer/farmer to set the clutch to his tractor and for the material being mowed. Most of my customers back off a turn at a time until they get a slip when they feel comfortable with the adjustment? Ken Sweet

I didn't realize this, but it's so true... Thanks.

I'll try that first, back off 1 full turn on each nut and see what that does...

 

[Agrantina]

I had the same problem with slip clutches and backed both mine out a 1/2 turn at a time unti I get it to slip then back 1 full turn. The only problem is that I understand that a slip clutch is for a impact hit-like a shear pin and is not designed for a slow load getting heavier and heavier like cutting grass. I do beleive that you can adjust the clutch to slip like you want it might just take you some playing with it to get it adjusted for a progressive load and not a sharp hit on a stump or something.. I have both mine marked and adjusted so they will slip before the tractor cuts off and will really slip if I hit something HARD..

AndyG

 

[dennis52]

Many farmers don't believe in "factory specs" for a slip clutch. How does the factory know what HP tractor is going to be attached to the implement and what type material is going to be mowed. These are variables that make it incumbent on the buyer/farmer to set the clutch to his tractor and for the material being mowed. Most of my customers back off a turn at a time until they get a slip when they feel comfortable with the adjustment? Ken Sweet

My new Brush Hog was set by the dealer to the factory specs for my tractor.

I did not fully read the manual where it spoke of fine tuning the settings after a a few minutes work and also to expect some initial wearing in.


The clutch started smoking and was red hot after a hundred yards of light slashing.

1/4 turn tighter on the nuts was enough to get it cucumber cool.

Has not slipped since adjustment, despite heavy work.

 

[slowzuki]

When you loosened it, did you break the disc free? I believe mine is supposed to have that done at the start of every season. Can't say I ever have though.

I borrowed a tiller from a friend that slips like mad, its slower than a 5 hp walk behind since it slips so much. Asked him about it and an employee of his smoked it until pieces of friction disc flew out. Never been the same since lol.

 

[dennis52]

When you loosened it, did you break the disc free? I believe mine is supposed to have that done at the start of every season. Can't say I ever have though.

I borrowed a tiller from a friend that slips like mad, its slower than a 5 hp walk behind since it slips so much. Asked him about it and an employee of his smoked it until pieces of friction disc flew out. Never been the same since lol.

My old slasher probably had the friction and metal clutch plates rusted on for at least 15 years before I realised and cleaned them up. It is only a 15 hp at pto tractor so that probably has saved the gearbox.

 

[Chilly807]

To my way of thinking, it should only slip under impact conditions. The tractor PTO is designed to work with the full power the engine can generate, so heavy loading should never hurt it. Impact load is a different situation however.

I'll try to set mine up so it slips a bit when mowing heavy grass, then tighten it a half turn more. Like we've said, if it gets warm when mowing under normal conditions, it isn't tight enough.

Sean