Woods Blower keeps snapping grade 5 bolts

[jigs_n_fixtures]

Can you spin the input easily by hand? If you can, do you feel any unevenness when you do?

I’m thinking there may be a bad bearing in the 90-degree gearbox, which is causing
it to bind up when input is applied via the PTO, but not when you turn the impeller, sending the load in from the other side.

 

[oosik]

Don't go to the grade 8 bolts. As suggested, try an alternate brand of grade 5.

Also thinking the "bad bearing/worn bushing" , as suggested by jigs could be the cause.

Obviously - something is binding up when you apply power. Is everything well greased up?

 

[RandyT]

If this thing has sheared several bolts over time the holes that the bolt goes through could be getting flogged out which can lead to the problem that you are having. But could also be a chipped gear in the drive box that is jamming when pressure is applied but may not show up when turning by hand.

 

[LD1]

Does the tractor ALSO have a foot clutch.

I know it isn't "needed" to engage PTO on most modern tractors. But if the clutch pedal does indeed disengage the PTO (it does on my Kubota MX)....by pushing the clutch, then engaging the PTO, it allows you to slowly engage the implement

 

[5030]

Chinese Grade 5 maybe?

 

[RoyJackson]

Does the tractor ALSO have a foot clutch.

I know it isn't "needed" to engage PTO on most modern tractors. But if the clutch pedal does indeed disengage the PTO (it does on my Kubota MX)....by pushing the clutch, then engaging the PTO, it allows you to slowly engage the implement

I doubt if too many TBNers have a gear tractor with a live PTO anymore. I had a couple in the old days (Deere 670 and 790), and LD1's post exactly describes the process. I'll add one thing...if the tractor has a foot throttle, be prepared to "blip" the RPM when engaging the PTO.

 

[LD1]

I doubt if too many TBNers have a gear tractor with a live PTO anymore. I had a couple in the old days (Deere 670 and 790), and LD1's post exactly describes the process. I'll add one thing...if the tractor has a foot throttle, be prepared to "blip" the RPM when engaging the PTO.

Yup, most of these small tractors anymore are HST. But up until 8-10 years ago....most still had a clutch.

Only recently have they gone away from that so they could put the split brakes on the left side.

Some like it that way. Personally I still prefer the clutch. Cause it still disengages the PTO. Doing alot of brush mowing....that's my first oh $hit instinct is to stop on clutch when something sounds amiss. And it also allows feathering the engagement.

I think the OP said his tractor was a 2002 model. I would think it still has a clutch.

The ONLY implements I use that I DONT feather the clutch to ease the engagement on are things with little inertial load. Like a seed spreader, or PHD.

 

[leonz]

A slip clutch ends up being mounted on the gear box side of the trailing implement but if there is little room it could be mounted on the stub shaft of the PTO.

 

[ruffdog]

Are the shear bolts shouldered through the shear area or are there threads at the shear point? If it is threaded, you may want to get longer bolts that have the longer shoulder, then cut off excess threads. Also, most use a locking nut and are just snugged...not over tightened.

 

[ArlyA]

The OP was doing fine with the grade 5 bolts, untill he wasn't. Something changed.