Drive shaft won't lock onto tractor's PTO

[rgr33]

Gary, you're one of the posters on here that is always worth reading. I agree with your point, and in fact that is what I do with my old rotary mower. Hate to see you insulting other posters, you are among friends here, they just have a different opinion to give.

 

[Quebecguy]

Soundguy,
I agree with you all the way. I admire your politeness and restraint after being insulted.

 

[Tx Jim]

I agree with Soundguy manufacturers suggested a bolt grade(strength) for a reason which is to protect drive shaft/gearbox from damage. Diagnose & repair the problem don't camouflage it with a higher strength shear bolt.

 

[Ford850]

I recommended slow pto engagement earlier, but it sounds like some tractors don't have that ability. If my tractor was only able to snap the PTO into action, and it resulted in many sheared bolts, I would add a slip clutch. If the shock of the drive engaging was so harsh that it sheared that many pins, I sure wouldn't want to continue it by using higher grade pins. Protecting the tractor would be my priority, and a slip clutch would do that.
Gary - you were talking about your BIL's tractor shearing so many pins. I'm wondering if you saw how the PTO was being engaged on that tractor. I know you said he did it at idle, but mine will still pop the pins sometimes if I just slide the PTO lever into gear. I have to ease mine into gear and then never shear a pin.

 

[JerryK]

I heard that Mahindra had a similar engagement problem when they first came out with the 35 series tractors. They ended up putting a small round hyd surge tank in between the PTO clutch pack and the elec hyd valve. Takes a little snap out of it. I broke a bunch of pins when I first got my blower. Some from everything brand new and tight... the others from the idiot operator working the clutch on my John Deere. Now, everything is loosy goosy... and I spent a lot of effort making a huge stash of new shear pins. So, now I just about never need one....

 

[momcilma]

Thanks for everyone's advice.
I was able to find a metals warehouse supply store that sold "307A CTI" bolts by weight so I got 20 of them just in case I popped a lot of them.
The manufacturer's website claims they are the same as a Grade 2.

Funny thing; I took one of the Grade 2 bolts that I got at a local tractor store along to compare size.
The head markings on the tractor store's Grade 2 labelled bolt exactly matched the "307A CTI" from the metal supply store.
$3 US at the tractor store versus $0.67 US at the metals store.

I raised the cutter deck(lowered the rear wheel) and was able to get the Woods cutter started OK. Now my cut height is about 5 inches.
I cleaned up the garden plot to get the corn and okra stalks ready for under-tilling. I'll do it again after the first frost hits this weekend.
Then I took it down the hill and cleared the brush about 50 feet into the woods before hitting some obstruction and the bolt sheared again.
I didn't want to start and stop the cutter so I just left it on all the time. I just raised it about a foot when I found something big in the woods.

I think I'll stick with the Grade 2 bolts and keep starting the cutter as slow as possible and don't turn it off until I'm done.

I noticed something else odd. When I first start the cutter I can hear the blades bang up against the center hub.
Once they are up to speed it almost sounds like prop wash from a helicopter at ideal.
I think another start up trick to avoid the banging against the center hub might be to hand rotate the cutting blade
back against the hub(with engine off and PTO disengaged of course) so they don't bang on start up.
The drive shaft turns very easily by hand so I think the shear pin was getting cut when the blades smacked up against the hub.

 

[bumperm]

It's best to find "big things in the woods" by either walking if first (not always doable of course), or by putting the bucket down all the way, cutting edge up maybe 5 - 8", in float, then go slow the first time. The idea is the bucket will find the rocks and logs before the shear bolt does.

Since the blades pivot, and they often get weeds and stuff between the blade and bolt, they'll sometimes be stiff and won't swing out right away on start up. It'll vibrate a bit until they do swing out. Not need to put the straight by hand, just go slow on the throttle until it smooths out. You can try using spray lube and working the blade pivot if one get's really tight. I've used all manner of grease on blade pivots, doesn't seem to make a lot of difference, won't last long, and they'll be right back to getting stiff again sometimes.