NH 469 Haybine question

[ridgeandvalley]

I've got an old NH 469 haybine that I use to cut less than 10 acres of hay twice a year. Last year during my second cutting, the bolt that connects the cutter bar to the wobble box sheared. I replaced it and finished up. Last week I was doing my first cutting and was about 2/3 done when this bolt sheared again. It was pretty warm when I picked it up. Replaced it again... sheared again 10 minutes later. Again, bolt was very hot, so there's a lot of friction happening. I gave up and brush hogged the last 2 strips. The hay wasn't extremely thick. Obviously something is going on, but I'm not sure what. Any thoughts?

 

[MJMJ]

Did you replace the bushing? If not, a worn bushing will cause the bolts to shear. I always replaced both at the same time.

 

[Northvale PA]

I use to run a 469. It would burn up the bushing about every 12 acres. I could almost count on it. Couple things I did: I always used a course threaded grade 8 bolt and torqued the heck out of it. It never sheared a bolt. But the thing that solved the bushing problem was replacing the wobble pivot arm bearing. That had slop in it which made the pivot arm allow heat build up,thus melting the bushing.

 

[4520BW]

dull blades and wore out guards will cause it.

 

[ridgeandvalley]

I had actually replaced almost all the sections before this problem began.

 

[mikewood869]

We had a NH 477 that did that, turns out the front of the mower was bent and then bent the cutting bar slightly. The thing that killed that mower was the axle.