Yanmar 1702 Shifter Bolt/Shear Pin?

[irishdude]

This weekend while moving some rocks around with my FEL, my shifter, which has been stubborn shifting into reverse, decided that it didn't want to go into either 2nd or Reverse anymore. I was stuck between a rock pile and the middle of our cabin driveway. After a little panic ensued I grabbed my wrenches and took apart the shifter turret and discovered that the little bolt/shear pin on the 2nd/Reverse shifter rod had indeed sheared off. So I swapped the good pin from the 1st/3rd side over and now I only have 2nd and reverse, but at least I can move my tractor until that one shears off at some inconvenient time.

I've tried Fred's and Hoye and neither seem to have one. It's #18 in the schematic and it's basically a 6x14 bolt with a 10 mm head
the threads are about 3/8" long with another 3/8" of smooth shaft/pin sticking out from the threaded end.

Any ideas? Have one made at a machine shop? Take a 6x14 bolt and turn it down myself?

 

[tier4]

you should try Fredericks importers 256-340-8899

 

[CoyPatton]

One huge caution about turning down a shear bolt yourself or having one made at a machine shop is that shear point!
It is your tractor do as you wish, but also realize going either of those routes means you have yourself only for determination of that shear point. To low and you are going into the gear box often, to high and what then becomes the weakest link in the transmission?

Personally, it is worth a lot of effort to find the correct part or at least as correct as is possible some 30+ years after the tractor was made.

 

[irishdude]

you should try Fredericks importers 256-340-8899

Like I said in the first post, Fred's was the first place I tried. I tried Hoye second. They actually knew what I was talking about and they are the ones who provided the schematic. They said they "might" have one that they could take off of a used tractor. You would think this would be a common wear item.

 

[irishdude]

One huge caution about turning down a shear bolt yourself or having one made at a machine shop is that shear point!
It is your tractor do as you wish, but also realize going either of those routes means you have yourself only for determination of that shear point. To low and you are going into the gear box often, to high and what then becomes the weakest link in the transmission?

Personally, it is worth a lot of effort to find the correct part or at least as correct as is possible some 30+ years after the tractor was made.

I'm not nearly as concerned about it as you. It's easy to remove the existing good one and measure it with calipers and fab a new one. It's it obviously designed to be the weak link in the chain with absolutely zero consequences if it fails (Other than not being able to shift.) Which is why I don't understand why this is not a commonly available replacement part.

It is actually called a "Dog Point Set Screw" and there are several available from aftermarket suppliers, but all of them are slightly different, with most if not all having an Allen head.

 

[Vbull]

I've had to make several different shear pin/bolts. Just to be on the safe side I have used grade 2 bolts as the base for the part. For through type pins I have used threaded rod which is also grade 2.
To date the ones I've made that had sheared, none have caused any damage to the shaft being protected. (I have a gravel driveway and the snowblower is hard on pins)