Posthole Digger Land Pride PHD shear bolt

[RobA]

I have a Land Pride PD15 post hole digger. Was using it a while ago and the auger stopped turning. I'm assuming the shear bolt broke but haven't had time to look at it. I looked at the manual before trying to fix it (and get myself in trouble as usual) and am confused as to how or what to try to fix. The PD15 does not have a clutch. The manual shows the shear bolt at the entire Eurocardan driveline (#12 in diagram, "Driveline (826-164C) Eurocardan Shear Bolt"). I don't get it.

[murphy1244]

There is two shear bots that attach the auger to the drive

[RobA]

Thanks, if that's the case #4 in the diagram must be the shear bolt. They have it listed as "HHCS 3/8-16X2 3/4 GR5" and "HHCS 3/8-16 X 2 3/4 GR2". Not sure why they are listing 2 different grade bolts.

[murphy1244]

Thanks, if that's the case #4 in the diagram must be the shear bolt. They have it listed as "HHCS 3/8-16X2 3/4 GR5" and "HHCS 3/8-16 X 2 3/4 GR2". Not sure why they are listing 2 different grade bolts.

Good question.

[murphy1244]

My oops my drawing shows #8 as the shear bolt drawing #14770

[Farmerford]

#4 is the shear bolt. #14 is the stud that screws into and through the universal joint yoke, and then into the groove in the input shaft to the gearbox; when the shear bolt shears and the yoke spins around the shaft, this stud keeps the yoke from slipping off the shaft because the stud extends into the groove and just spins around in it.

Shear bolt breakage is a common occurrence with PHD's; I actually built a little bracket that bolts to the gearbox on my Bush Hog PHD to hold spare shear bolts.

If you can't find a factory replacement, just get a grade 3 hex bolt the same size as the sheared bolt; grade 3 is the weakest grade and it is unlikely the factory bolt would have been made of anything with less shear strength. In my experience, the shear bolts on PHD's are to protect the drive shaft; they are fairly long to reach from the tractor PTO to the gearbox when the PHD is raised completely, and to save money the manufacturers use a light grade of drive shaft.

A few manufacturers use a shear bolt with a reduced size on the thread end; I am not sure whether that is to drive you back to the dealer for replacements or to discourage you from using hex bolts from the hardware store because you might get a grade 5 or 8 bolt that is much stronger than the grade 3 and might not shear before the driveshaft were damaged. If that is the case, just drill out the smaller hole in the yoke to the same size as the larger hole in the other side of the yoke.

[murphy1244]

Thanks for the comeback Farmerford, That #4 is # 8 on my drawing that's why I put the drawing# on the post

[Farmerford]

OOPS: I took so long to write my response (got interrupted by business) that you got more responses that gave you good advice. Since Land Pride says a Grade 5 bolt is okay, I would use a Gr 5 replacement unless something else in the manual tells you that the GR 5 is only for certain drive shafts.

[RobA]

Thanks for the replies and help. Now it makes a lot more sense. I'll probably pick up several grade 5 bolts today and try to fix it this weekend.

[murphy1244]

Thanks for the replies and help. Now it makes a lot more sense. I'll probably pick up several grade 5 bolts today and try to fix it this weekend.

Post what size you get for the next guy who does a search.