Shear bolt my rear

chas0218 · Mar 8, 2020

I bought a used 5' howse rotary mower. It had a shear pin style pto. Well the previous owner broke the pto guessing either hit something or the shaft wasn't working right. Whatever the issue he snapped it.

This is where my problems started. I removed the shear pin and tried to slide the shaft off, yeah right this probably has 15 years of rust keeping this thing on. So my endeavor started with trying to remove the completely shot universal joint. I managed to get 1 snap ring out and pound the universal from one side allowing me to get the angle of the dangle and slide it out.

Well now that I got the universal apart time to get that yoke off. Grabbed my 2 jaw puller and and got to work. Holy crap 2 hours later heating, spraying, tapping, heating some more, etc. I got it to move then another 30 minutes of tightening and tapping got her off.

I now have a bolt on slip clutch and pto shaft ordered. No more of this, I'll still take the pto off yearly and grease the shaft but I'm not going to rely on the shear pin to work when or if it gets rusted on.

PCABE5 · Mar 9, 2020

What bolt on slip clutch did you end up with?

Avenger · Mar 9, 2020

As I was reading your post, I was thinking to myself "he needs a new shaft with a slip clutch." Only so much heartache before I scrap it and go get another, especially with something like a shaft. :thumbsup:

chas0218 · Mar 9, 2020

PCABE5 said:
What bolt on slip clutch did you end up with?

Below is the one I ordered. I'm betting I will need to trim it to fit but that isn't a big deal. Says it is for a Howse 5' or 6' so we will see. It is a bolt on slip clutch with shaft all in 1 unit.

HOWSE PTO SHAFT SHEARPIN SLIP CLUTCH FOR MOST ALL 5 & 6 ROTARY CUTTERS | eBay

PCABE5 · Mar 9, 2020

Pretty good price for a clutch and shaft. Thanks for the info.

chas0218 · Mar 12, 2020

Anyone know what the minimum clearance would be from bottoming out a pto shaft should be?

The closest it gets is about 3" from bottoming out. I was thinking the more overlap the better.

LS Tractor Owner · Mar 13, 2020

I just cut a new shaft that came with a new mower, I left exactly 3 inches of room before bottoming out. That is the minimum at full drop, it gets to about 2 inches when the shaft is perfectly horizontal, then goes back to 3 inches when the mower is fully lifted. I agree that the most overlap is better.

ruffdog · Mar 13, 2020

A frozen clutch is just like a rusted up shear pin connection. Both need service every spring to ensure they will work as they should.

ovrszd · Mar 14, 2020

ruffdog said:
A frozen clutch is just like a rusted up shear pin connection. Both need service every spring to ensure they will work as they should.

Yep. The clutch actually requires more maintenance. Especially if the cutter sits outside.

And in the end, in this case, still relying on a shear bolt.

PCABE5 · Mar 15, 2020

chas0218 said:
Anyone know what the minimum clearance would be from bottoming out a pto shaft should be?

The closest it gets is about 3" from bottoming out. I was thinking the more overlap the better.

If I look through my Bush Hog manual they say that if it gets less than 2" you should shorten the shaft. So if you are at 3" you should be fine.