Rotary Cutter Slip Clutch Not Slipping

   / Slip Clutch Not Slipping #1  

Travis_R

Veteran Member
Joined
Jun 10, 2004
Messages
1,568
Tractor
Yanmar YM2500
Ok, how difficult is it to take the slip clutch apart and "free it up" so it will slip when it needs to, instead of killing the tractor like it's doing now when the bush hog hits something hard? I've never messed with a slip clutch before. This is the 1st attachment I've ever owned with a slip clutch...

It's a Bush Hog model 285. It hasn't slipped since I bought the cutter new last year or year before last. It's winter time and I'd like to get it fixed now while I don't need the cutter.

Thanks!
Travis R
 
   / Slip Clutch Not Slipping #2  
It's not hard, you probably don't need to take it apart anyway. For a bush hog, the recommended procedure is to loosen up all the nuts on the bolts, make a chalkmark on the disc's, and then engage the pto and drop the bush hog onto a thick brush pile. This should force the clutch to slip, which you can verify by looking at the chalkmarks. If it does slip, then you have freed it up, all you need to do then is to tighten up the correct amount so it doesn't slip under normal use. There is a chart that tells you how much to tighten the nuts, but it goes by the amount of threads exposed on the bolts to set the correct tension on the springs, not sure if that is a "universal" way to do it? I saved a copy of it somewhere on my pc.

I guess if the slipclutch is on a rototiller, you would do the same thing, only try and till some unbroken ground to get the clutch to slip. Once it slips, retighten till it doesn't slip during normal use.
 
   / Slip Clutch Not Slipping #3  
It's not hard, you probably don't need to take it apart anyway. For a bush hog, the recommended procedure is to loosen up all the nuts on the bolts, make a chalkmark on the disc's, and then engage the pto and drop the bush hog onto a thick brush pile. This should force the clutch to slip, which you can verify by looking at the chalkmarks. If it does slip, then you have freed it up, all you need to do then is to tighten up the correct amount so it doesn't slip under normal use. There is a chart that tells you how much to tighten the nuts, but it goes by the amount of threads exposed on the bolts to set the correct tension on the springs, not sure if that is a "universal" way to do it? I saved a copy of it somewhere on my pc.

I guess if the slipclutch is on a rototiller, you would do the same thing, only try and till some unbroken ground to get the clutch to slip. Once it slips, retighten till it doesn't slip during normal use.
You would be pretty much accurate. Loosen the retaining bolts, engage tiller to the ground, let it slip, then tighten bolts to specifications(mine has an exact measurement).

Hope this helps
 
   / Slip Clutch Not Slipping #4  
Are you sure it doesnt slip? Next time it stalls your tractor get off and lay your hand on the clutch. If its even as warm as the gearbox it has slipped a few revolutions as you stalled. That is about perfect. Just loosen it a quarter turn. If you go too far it can slip too often and without you knowing it, and will wear down and need frequent readjustment.
larry
 
   / Slip Clutch Not Slipping #5  
Bush Hog recommends that the slip clutch be loosened and slipped periodically (once a month?) to prevent it from freezing up. I know, I haven't done it on mine yet :( The procedure is in the manual. If you don't have the manual, check their website and see if you can download it.

My 10 year old Woods does not have that requirement IIRC. That's one drawback to the Bush Hog brand IMO.

I'm guessing that the clutch in the Bush Hog can rust together and that's why they require the periodic loosening and slipping.

Ken
 
   / Slip Clutch Not Slipping #6  
As well said, I wouldn't take it apart either. Loosen (keep the distance the same all around) 'til it slips, then tighten 'til it just doesn't slip. May take a few trials to do work and not slip the clutch. But "frozen" or too tight is something to try to avoid.
Once a year should be enough re-sets.
 
   / Slip Clutch Not Slipping #7  
If it's the same style as the slip clutch on my King Kutter tiller, it's not hard, but may not be as simple as the guys above have suggested. After 2 years, with the nuts on all 8 tension bolts loose, mine would still stall the tractor through the PTO before slipping. It turns out that there was just enough rust between the bolts and the drums on 3 of the bolts that the drums wouldn't separate at all, keeping the clutch engaged. I didn't have to actually disassemble the clutch to fix it. I simply tapped each bolt from the nut end (using the nut as a thread protector) until all were free.

I removed each bolt and put a thin film of grease on the shank before reinstalling in hopes of preventing this from happening again.
 
   / Slip Clutch Not Slipping #8  
I had a slip clutch rust together on my Woods Brush Bull. Not a big deal to take it apart. Loosen and remove all nuts and knock bolts out of holes. There are 2 discs in there and mine were frozen solid together. They're kind of like round brake pads. I think I paid about $12 for two new discs. I also sanded the metal faces of the clutch so there were no old burrs or rough spots to catch or stop the discs. Re-tighten to the spec in the manual. I think it said leave 1 3/4" of thread exposed above the nut head. Be sure to tighten the bolts in some sort of sequence a little at a time. Before I was done and while the bolts were still a little loose, I spun the disc by starting the tractor and engaging the PTO. You need to be sure to do this at least once a year (loosen bolts and engage PTO). This assures that the discs have "seated" to one another and that it functions properly.
Good luck! :thumbsup:
 
   / Slip Clutch Not Slipping #9  
You replaced yours for $12? Where did you get them for that price? I've been quoted close to $100...
 
 

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