New Holland baler 273 - Shear bolt at the flywheel breaking off

[Alpagas]

Hello all

We bought this baler last year and had a hard time while baling as the flywheel shear bolt kept breaking off. I read that it was probably the brake of the needles that were worn behond adjustment so i kept disengaging the PTO at each bale so the needle when coming back would not hit too hard. (Forgive my english, i hope its clear) Do you agree that i should start by changing and adjusting the brake or is there something else i should check?

Thanks

 

[MH8675309]

How fast are you running that baler? Try throttling down to a slower RPM and also dont feed it too fast. If the windrows are heavy - go slower. You might just be jamming it by taking in too much hay too fast. Good luck

 

[Tx Jim]

Has anyone checked baler to be sure it's timed correctly? I agree a good operating needle brake is a requirement for good baling. Is PH & stationary knife clearance in spec.?

 

[zzvyb6]

Are you using 'real' shear bolts or just some regular off the shelf bolts? The real deal fit the pin hole better and are less likely to shear during a normal cycle. This will be a problem if the pin holes are all wickered out and or the flywheel bearings are very worn. Sharpen the plunger knife and stationary knife. Run the machine at the rated pto rpm so the flywheel assist contributes to the bale compression.

Is your bale weight correct ? If they are very heavy, or the hay is damp, or the timing is off, you will be shearing safety bolts.

 

[leeave96]

Without a doubt, the New Holland 273 was and is one of the best balers they ever made. It should not be shearing flywheel bolts.

Firstly - if you don't have a manual, get one! With a credit card, you can download a PDF manual from New Holland's website. You can print the pages, some or all. I keep them on my tablet such that I can reference them while working on my baler.

You will need to check the timing. New Holland balers are very easy to time. Timing is important because, if it is off, the needles will try to come into the chamber prematurely on the compression stroke, a wad of hay gets between them and the plunger face and BAM, you're buying new needles in addition to a manual. However, if the plunger stop is in working order, then it will stop the plunger cold and your flywheel bolt will shear as it should.

Once you've verified timing is per the manual - other things to check out.

The easiest thing is this: Contrary to your instinct - run the baler at full 540 PTO rpms. This makes the flywheel work and as the tractor power recovers, bringing the flywheel/plunger back up to speed after a compression, less stress is put on shear bolt.

As Jim said - check the plunger knife to stationary knife clearance. It should be about 1/32 inch. If you have a large gap, the plunger can't "slice" as easy and could cause the flywheel bolt to shear as the tractor PTO speed tries to recover from lost momentum. This gap can also contribute to a banana bale shape too.

Other things can be worn flywheel bushing and the flywheel wobbles and in rare cases (that I've heard) the insert for the shear bolt can be worn too.

ABSOLUTELY use New Holland's flywheel shear bolts. They are cheap enough.

Once I corrected some of the above - and especially started running at 540 rpms, my baler quit shearing flywheel bolts - a New Holland 68.

Good luck,
Bill

 

[aczlan]

As Jim said - check the plunger knife to stationary knife clearance. It should be about 1/32 inch. If you have a large gap, the plunger can't "slice" as easy and could cause the flywheel bolt to shear as the tractor PTO speed tries to recover from lost momentum. This gap can also contribute to a banana bale shape too.

I will have to check that on ours, it sometimes wads up and doesnt cut when you are in a heavy windrow.

ABSOLUTELY use New Holland's flywheel shear bolts. They are cheap enough.

That is PN 633169 correct? I have been using grade 5 bolts (long enough that the "shear line" is on the unthreaded shank), but those are cheap enough that I should grab a dozen to throw in the baler toolbox.

Aaron Z