bush hog brand PTO issues

[yanmars]

I have a Bush Hog brand model 306 brush cutter. It has the slip clutch. The PTO shaft has a female and male and they will not fit together fully. They only engage about 3 or 4 inches. That makes it too long to fit to the PTO stub on the tractor and even if it did I feel it would be too little engagement for strong operation. Any ideas here to get it to fit together? The female round tube has a few small dents but I do not think it interferes. I have the internal spline lined up properly to engage. Thoughts?
Also I bought this used. Does the slip clutch have to be loosened/checked to make sure it is not stuck in any fashion. I think it was shedded most of the time but has some hour our of doors?
The Bush Hog is also a Cat II. The tractor is a Cat I. I have some bushings to fit the size differences but they need to be cut to fit. Any ideas on any way to handle this other than that? Thanks

 

[Texasmark]

Probably rust down in the shaft interface. 3-4 inches you ought to be able to see down that far with a light. You got the main part right, the marriage. The marriage is required to ensure that both joints bend in the same direction. If not for the deliberate misalignment one could have the joints 90 degrees apart and that wouldn't work.

On the slip clutch, measure the spring length before you do anything else and record the number....all should be the same so if various, take the average value for your number.

Remove the nuts and springs and separate the thing. Shine up all the metallic and clean up the friction discs interface surfaces. Put it all back together and in tightening the nuts, leave the springs about half an inch longer, all the same length.

Find some tall, thick grass and drive into it and get the blade to stall out. Start tightening the nuts a turn at a time till it quits slipping when you get into the grass....makes the tractor start lugging before it slips. Measure the springs. If they were set right by the PO then they should be the same length as when you started. If not, use your numbers.

 

[JRobyn]

No need to disassemble the slip clutch, but they all MUST be "serviced" once a season. Just airborne moisture is enough to rust and seize the friction plates to the pressure plates. It's fairly easy to do. As noted, first check your beginning spring length, or better yet, e-mail Bush Hog and ask them to send you a pdf of the owner's manual including clutch maintenance instructions and correct spring length.

Then, with the implement and PTO shaft connected, loosen all of the springs at least a few turns. Start up your tractor and "roughly" engage the PTO at some reasonable RPM between idle and PTO speed. You should be able to see and hear the clutch SLIP and be able to tell that the blades are NOT spinning up to regular speed. I find that the breaking loose and slipping often happens when the PTO is DISengaged and the cutter puts reverse torque on the clutch. When it does break loose and slip, it is often accompanied by a small cloud of rusty iron dust. It may take a few engage/disengage cycles. You shouldn't need to actually bog down the cutter to make this happen.

Letting it spin once or twice for just a few seconds is sufficient to clean and polish all the friction surfaces. Too long and you run a risk of overheating things.

Then tighten each of the springs back down to the correct length. You may want to let the clutch cool off just a bit first, especially if you don't heed the advice to keep the slipping/spinning to a minimum.:fiery:

The "tighten a bit at a time by trial and error" method cited above also works, but there is a real risk of leaving things just a bit too loose and frying your friction disks. Then you WILL need to completely disassemble and replace them and maybe the expensive pressure plates and/or hubs too. Don't ask me how I know this!:ashamed:

 

[yanmars]

I did not think I was going to get the two shafts together. I was going to disconnect the rear shaft from the slip clutch/gear box but that was "welded" on. Tried one last time and got the PTO shafts to mate so good to go. Now to see if the bushing are the correct length so I can use this Cat II bush hog with my Cat I tractor.

 

[art]

Just a quick note, if those shafts do not slide easily you will ruin the next weakest link which could be the rear end of the the tractor where the PTO shaft sticks out! Just saying, we do like that work in the shop as it is often several thousand dollars of repairs!

 

[Texasmark]

No need to disassemble the slip clutch, but they all MUST be "serviced" once a season. Just airborne moisture is enough to rust and seize the friction plates to the pressure plates. It's fairly easy to do. As noted, first check your beginning spring length, or better yet, e-mail Bush Hog and ask them to send you a pdf of the owner's manual including clutch maintenance instructions and correct spring length.

Then, with the implement and PTO shaft connected, loosen all of the springs at least a few turns. Start up your tractor and "roughly" engage the PTO at some reasonable RPM between idle and PTO speed. You should be able to see and hear the clutch SLIP and be able to tell that the blades are NOT spinning up to regular speed. I find that the breaking loose and slipping often happens when the PTO is DISengaged and the cutter puts reverse torque on the clutch. When it does break loose and slip, it is often accompanied by a small cloud of rusty iron dust. It may take a few engage/disengage cycles. You shouldn't need to actually bog down the cutter to make this happen.

Letting it spin once or twice for just a few seconds is sufficient to clean and polish all the friction surfaces. Too long and you run a risk of overheating things.

Then tighten each of the springs back down to the correct length. You may want to let the clutch cool off just a bit first, especially if you don't heed the advice to keep the slipping/spinning to a minimum.:fiery:

The "tighten a bit at a time by trial and error" method cited above also works, but there is a real risk of leaving things just a bit too loose and frying your friction disks. Then you WILL need to completely disassemble and replace them and maybe the expensive pressure plates and/or hubs too. Don't ask me how I know this!:ashamed:

Designer's choice on whether to or not to disassemble. I like to look and see on something like the clutch. On burning up if too loose, you know when it's too loose.....it doesn't cut grass and it only takes a few feet to realize that.

My opinions.

 

[JRobyn]

Designer's choice on whether to or not to disassemble. I like to look and see on something like the clutch. On burning up if too loose, you know when it's too loose.....it doesn't cut grass and it only takes a few feet to realize that.

My opinions.

Unless your wife REALLY likes to bushhog, and spinning at about 1/2 of normal speed will still cut the moderately thick grass, and she doesn't hear or smell anything unusual until after 3 or 4 hours of cutting. One of my two friction disks was completely GONE!

 

[Texasmark]

Unless your wife REALLY likes to bushhog, and spinning at about 1/2 of normal speed will still cut the moderately thick grass, and she doesn't hear or smell anything unusual until after 3 or 4 hours of cutting. One of my two friction disks was completely GONE!

"Stuff...happens" Sorry for your loss. I work alone. Wife of 49 years had a heart attack in 2010 and didn't survive it.

 

[JRobyn]

Very sorry to hear. Condolences and prayers for peace. If anything happened to my wife, *I* wouldn't survive it.

 

[boggen]

cat 2 rotatory mower on a cat 1 tractor.

rotary mower = bought used.

my first re-action. is the PTO shaft the correct length. if it is to long. and you raise up the mower, you can damage something. you can cut PTO shafts down to correct lengths. i do not remember the correct suggested length for overlap. when i say raise up the mower, generally when you lift up the 3pt hitch and the shaft is pretty much level from connection point on back of tractor to connection point on implement = shortest distance. that you need to take into account.

most PTO shafts should have some sort of grease zerks on them to grease them up. old shafts may not. if that is case, pull PTO shaft apart and lube it up some and put it back together so it slides easier. ((some times PTO shafts will rust up and be a pain to pull/push apart))

(Temporarily blocked due to reports of company closure) = they have a descent video of smoking a new slip clutch and how to adjust it. (new slip clutches can have a varnish/wax on them. and smoking them when first new, can remove that stuff, so the slip clutch begins working correctly from understanding)

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to note it. some times PTO shafts have a "sheer bolt" instead of a slip clutch, the sheer bolt is suppose to be cut apart, if mower hits something. so the force does not travel back to tractor and damage tractor. size the sheer bolt for weakest link. in your cast the tractor. the mower being CAT II should have beefer parts on it for bigger tractor.

to note it. double check what RPM's mower wants, CAT II mowers can have a 1000RPMs vs a 540PM PTO.