Bush Hog Troubleshooting

[LD1]

I wouldn't be shocked if I blew the math. I'm used to it. Plus, I'm relying on memory and that's even worse than my math.

Well, the few 4 footers that I have ran across have at least a 1.5:1 box.

1.5 x 540 PTO RPM means that the blades are spinning @ 810 RPM.

With a 4' diameter tip-to-tip, 4 x pi = 12.56' circumfrence. In other words, the blade tip travels 12.56' every revolution.

12.56' x 810 RPM = 10,173 FPM tip speed.

10,173 x 60min per hour= 610,380 feet per hour

610380/5280= 115 MPH:thumbsup:

ANd just a quick look at landpride specs shows their 48" cutter having a 16,203 FPM blade speed and a 1:2.83 gearbox. That is 184MPH:confused2:

 

[Short Game]

Well anyway, my point was my blades, even when new, had rounded leading edges. If the blades are going the intended speed, and not slowed down independently from the PTO shaft, most any vegetable matter smaller than tree trunks should be getting chopped off. For the OP, it just seems like those blades must not be keeping up with the engine and PTO if the revs are staying up there.

Last spring it stopped cutting and went to just bashing grass and weeds.

I just don't think it would have been like that if it was the blades.

 

[Coyote machine]

Well anyway, my point was my blades, even when new, had rounded leading edges. If the blades are going the intended speed, and not slowed down independently from the PTO shaft, most any vegetable matter smaller than tree trunks should be getting chopped off. For the OP, it just seems like those blades must not be keeping up with the engine and PTO if the revs are staying up there.



I just don't think it would have been like that if it was the blades.

I agree- it's NOT the blades it's LOST RPMs from the PTO to the blades via the gearbox/slipclutch; therefore not enough RPMs where they're needed- at the blades!:thumbsup:

 

[Farmwithjunk]

A few years ago, I sold a bush hog to a neighbor. He called me a couple weeks later to say "This one doesn't work either".... After a couple questions, I found out he bought mine because he THOUGHT his older one had "issues". When the one he bought from me did the same EXACT thing., (ie, not cutting weeds) I paid him a visit.

Found out the PTO clutch ON THE TRACTOR was on the fritz. It would turn the pto shaft until a load was applied, then it would slow down enough so that the mower quit cutting, but not so much that the untrained eye could detect the shaft running @ 1/2 speed.

Not saying that is the problem, but yet another "possibility".

 

[Master Deluxe]

That's what I think too.
Those blades need to be turning at pretty high blade tip speed. If the weeds are getting "bashed", I'm assuming you mean knocked down, but not cut. That suggests those blades aren't turning fast enough to do the job.
So, go the cheapest route first...slip clutch (if installed). I can't see how the cutter's gearbox could be at fault as it's just a couple simple bevel gears.


Master Deluxe, do you have any other PTO powered implements and are they operating correctly? Any chance of borrowing another cutter to see if that one does cut properly?

I do have a clutch, I have experienced slipping. This time if it is slipping it's not much. I'll tighten it a bit. No other PTO driven stuff PTO shaft is turning pretty vogorously. Thanx.

 

[Master Deluxe]

A few years ago, I sold a bush hog to a neighbor. He called me a couple weeks later to say "This one doesn't work either".... After a couple questions, I found out he bought mine because he THOUGHT his older one had "issues". When the one he bought from me did the same EXACT thing., (ie, not cutting weeds) I paid him a visit.

Found out the PTO clutch ON THE TRACTOR was on the fritz. It would turn the pto shaft until a load was applied, then it would slow down enough so that the mower quit cutting, but not so much that the untrained eye could detect the shaft running @ 1/2 speed.

Not saying that is the problem, but yet another "possibility".

I don't think the tractor's PTO has its own clutch - certainly none I can detect. I've burned a bush hog clutch before and know what it looks and smells like. In case I have a little slippage, I will tighten it up a bit.

 

[SSdoxie]

There is also a hub at the stump jumper, some are splined others a simple keyed shaft. Key could be sheared allowing blades to slip on the output hub.

 

[Soundguy]

I don't think the tractor's PTO has its own clutch - certainly none I can detect. .

Your xray vision must be failing you

a JD 5310 should have independent pto, and thus a clutch pack.

I've replaced a clutch pack in a few independent JD pto's.. last one was in my step fathers 2240... nice fun job too.. wasn't cheap.. hope yours is ok.

his pto did the same.. it would spin under no load or lil load.. but take it out to mow and it would stop. cleaned the lil long tube screen, still nada. rebuilt the clutch pack with all them media discs and it spun like a charm.

you list a 5310 in your profile.. so I assume that is what you have..

soundguy

 

[Master Deluxe]

There is also a hub at the stump jumper, some are splined others a simple keyed shaft. Key could be sheared allowing blades to slip on the output hub.

The best I recall mine is keyed. I see no evidence of a busted key. I'll probably find out soon. Dealer should have a new set of (******, shorter) blades for me tomorrow - Thursday. So I may soon be digging into all this stuff.

 

[Master Deluxe]

Your xray vision must be failing you

a JD 5310 should have independent pto, and thus a clutch pack.

I've replaced a clutch pack in a few independent JD pto's.. last one was in my step fathers 2240... nice fun job too.. wasn't cheap.. hope yours is ok.

his pto did the same.. it would spin under no load or lil load.. but take it out to mow and it would stop. cleaned the lil long tube screen, still nada. rebuilt the clutch pack with all them media discs and it spun like a charm.

you list a 5310 in your profile.. so I assume that is what you have..

soundguy

Tell me about independent PTO's. My PTO is buried below the fuel tank. The only clutch pack I've found is in the drive shaft to the gearbox that swings the stump jumper - and thus blades.

I'm only willing to work just so hard and long on this. At some point I may have the dealer come and get the whole rig and make it work. I have no ambitions for being a tractor mechanic. I have gotten way behind this summer on a street rod project that is important to me.