JD 336 square baler sheer pin

[farmerwanttobe]

Hello,

I bought a used John Deere 336 baler. I baled about 200 bales fine. While baling, I noticed the fly wheel had sheered a pin. But it was still baling. I shut it down. the flywheel was spinning free. Started back up and still was making a bale. I thought a flywheel sheer pin would shut you down? I did replace it and maybe it baled a little better. Does anyone have any thoughts on this.

Thanks All

Steve

 

[Tx Jim]

My 1st thought is the slip clutch is stuck. Actually the flywheel shear bolt only powers the flywheel which relieves torque(stress) on driveline. Freeing up slip clutch helps slow down shear bolts shearing for no apparent reason. Slip clutch is intended to slightly chirp(slip) with each plunger head stroke.

 

[farmerwanttobe]

Thanks TX Jim. I'll keep an eye on the clutch.

 

[zzvyb6]

The situation you've run into is not that uncommon. You can fracture a shear bolt for many reasons besides a plunger stall. The wrong shear bolt (They are not just TSC's cheap stuff, they are a specially made high shoulder bolt that should fit the flywheel and the crank arm kinda tight), a worn flywheel bearing or gearbox shaft, too fast of the pto engagement and a large stick or mass that the plunger encounters yet breaks it through. The momentary plunger deceleration may be enough to break the shear pin. If the reason for the lurch clears, you will be able to keep baling without noticing the flywheel is free-wheeling.

Sounds like the machine is in good shape because otherwise you would hear the tractor governor grunt at each plunge, OR, you tractor's driveline has more that enough rotary inertia to make up for the loss of the flywheel assist.

If you were using a kicker pan however, it's hydraulicly driven from belts around the flywheel. If there's no shear pin in place, there won't be any hydraulics and no bale tossing.

I disagree that the slip clutch incrementally indexes with each plunge. That would wear it out in no time. If that's happening, your knives are dull, the plunger bearings are jammed, bales are too tight, or your driveline is not indexed properly (U-Joints are out of phase), or the slip joint is too loose or already worn out.

 

[vsteel]

They are also a wear item. I have them last about a 1K to 3K bales before one goes (assuming nothing bad happens). The flywheel is just to smooth out the plunger strokes. You can bale without it but it will cause the tractor engine to surge more, though depending on the power of the tractor you might not notice it much. Get a bag of them from the JD dealer and keep them in the little box under the plunger arm lid.

I have never had the clutch slip unless something went wrong. As mentioned having it chirp each stroke will wear it out in no time.

Just wait until something happens and the needles don't pull out of the bale and the safety arm catches the plunger arm. The noise and dust that comes up from the baler is huge. You will have to replace the shear bolt then as well.

 

[Tx Jim]

I have never had the clutch slip unless something went wrong. As mentioned having it chirp each stroke will wear it out in no time.

Please read this slip clutch information copied from JD sq baler operators manual. I stand by my statement that a correctly adjusted,non stuck sq baler slip clutch should chirp with each plunger head stroke. I was taught this info when I attended JD service school.

 

[kuboman]

Please read this slip clutch information copied from JD sq baler operators manual. I stand by my statement that a correctly adjusted,non stuck sq baler slip clutch should chirp with each plunger head stroke. I was taught this info when I attended JD service school.

A slip clutch that is set too tight will cause premature wear on the driveline and ultimately failure. It will also cause failure of the pto in the tractor. Having run balers for 45 years i consistently run the clutch even looser than the factory recommends. It is far cheaper and easier to rebuild the slip clutch than any of the other mentioned parts.
Just my experience.

 

[vsteel]

Please read this slip clutch information copied from JD sq baler operators manual. I stand by my statement that a correctly adjusted,non stuck sq baler slip clutch should chirp with each plunger head stroke. I was taught this info when I attended JD service school.

I would have to look at our 1978 manual to see if that is in there, I don't remember anything about the clutch slipping on each stroke. Is that maybe a later manual?

We always had it adjusted to the correct length but if it is slipping I have never heard it chirp. This is with the same baler and same tractor since 1978 and at least 100K bales through the baler. Have not ever tore into the tractor PTO for any reason.

 

[zzvyb6]

Official John Deere baler specs for slip clutch torque on a 336 is 400 - 500 ft-lbs. Meaured with a 10 foot long pole and a spring scale with a wood block between the knives.

There's a typo in this chart: the "366" is actually "336" as is repeated in a later section of the manual.

 

[Tx Jim]

I would have to look at our 1978 manual to see if that is in there, I don't remember anything about the clutch slipping on each stroke. Is that maybe a later manual?

We always had it adjusted to the correct length but if it is slipping I have never heard it chirp. This is with the same baler and same tractor since 1978 and at least 100K bales through the baler. Have not ever tore into the tractor PTO for any reason.

Did you ever take time to read what your baler operators manual stated about the slip clutch??