Tractor Repair: new holland hayliner 275 wire baler, shear bolts, frequent shearing

Question
Can't get needle yoke and knotter to return to "home" position after cycle and shearing flywheel shear bolt. I have tried adjusting the needle yoke rod,needle timing- late and early,plunger safety stop,knotter brake,and chain all by the book and by timing the needles in chamber. There appears to be no slop or worn out joints(Doesnt shear bolt every cycle but often)Please Help-Thankyou

Answer
Hello,

  There are no wire balers in this part of the world, so I have never had the opportunity to work on one, but many things on a twine baler will still pertain to this problem.  Sounds like you have been doing a pretty thorough job and have done the right things so far.  Many things can cause flywheel shear bolts to break, but if it always does it near the end of the tying cycle, it is usually timing related and the safety stop is not being retracted soon enough.  The very tip of the safety stop being battered and mushroomed is evidence of that. When you say that you timed the needles in the chamber, I assume that means that you timed them to the plunger, which is the best way.  Going by the timing marks almost always results in late timing and causing the problem you are having.  The marks are OK when a baler is new, but as things wear and chains stretch, the marks can't be relied on anymore.  The tips of the needles have to start entering the chamber just as the tips of the plunger are even with the tips of the needles as the plunger is on it's rearward stroke.  Safety stop adjustment is very important, so it is good that you have already done that.  The needle yoke rod should not need adjusting.  Worn knotter clutch parts or a broken knotter clutch spring can cause the clutch to kick out part way through the cycle, so check that also.  A loose flywheel, worn shear bolt hole, incorrect shear bolts, a siezed up flywheel slip clutch, and loose plunger bearings can cause frequent shearing also.  Trip the knotter clutch and turn the flywheel by hand to run the baler through a complete cycle.  Listen for unusual noises, anything hitting somewhere, and watch how close the safety stop comes to hitting before it is being retracted.   As a baler gets old and worn, sometimes you have to ignore the book and adjust things outside of the specs to get it to work.

                   Good luck,

                         Arnie