Mowing new holland 477

[richardturner]

keep breaking shear pin between wobble drive and knife am i going too fast or am i using wrong strengh of shear pin

 

[art]

There are several possible reasons, does the cutter bar move easily and smoothly?

What grade bolt are you using?

Are the holes egg shaped?

 

[sweettractors]

I ran a 477 for many years and only used NH shear bolts. The sickle blade should slide back and forth easily in the cutterbar, Ken Sweet

 

[richardturner]

The cutter bar does not move freely is there something I should look for

 

[sweettractors]

The cutter bar does not move freely is there something I should look for

Yes, Look for the rock guards to all be in alignment and make sure the sections are all tight on the sickle. In addition, make sure the hold down clamps are all in the correct operating position. Ken Sweet

 

[zzvyb6]

It's NOT a shear pin. Its a drive bolt: especially hardened. Sounds like you have other problems. Remove the cutter bar if possible and align the rock guards and straighten the knife bar. If the bushing is shot, get a new one. There is no slack or play in the knife bushing.

 

[Fastcars63]

The bolt is a grade 8 and should be tighten as tight as you can get it and then go another round. All the mounting stud should be round and not oval. The sickle should slide in the guards freely without much resistance. Make sure the bushing is a OEM and that its adjusted properly