PTO Shear bolt issues

[Brian B Glynn]

I have a 1952 WD45 and cannot keep a PTO shear bolt in place. I've tried different bolts including a Grade 8 bolt but they always break within several minutes. The PTO unit seal was replaced last year if that makes any difference. The brush hog works well before the bolt breaks. Any ideas?

 

[JoeM(GA)]

is the hole in the tractor shaft or the yoke loose on the bolt? Grade 8 is a good way to break something expensive or hard to find!

 

[DoubleO7]

I have a 1952 WD45 and cannot keep a PTO shear bolt in place. I've tried different bolts including a Grade 8 bolt but they always break within several minutes. The PTO unit seal was replaced last year if that makes any difference. The brush hog works well before the bolt breaks. Any ideas?

As Joe said, all the holes that the shear bolts goes thru need to be round and as close to the same size as the shear bolt as possible.
Any wallowing or elongation of the holes allows the two pieces to hammer the bolt until it shears.

 

[Aaron SEIA]

Its not supposed to be a shear bolt. Have you tried using the correct shouldered bolt? What are you trying to brush hog? Will it stay together if it's just running cutting nothing?
AaronSEIA

 

[Richard Nixon]

I have a 1952 WD45 and cannot keep a PTO shear bolt in place. I've tried different bolts including a Grade 8 bolt but they always break within several minutes. The PTO unit seal was replaced last year if that makes any difference. The brush hog works well before the bolt breaks. Any ideas?

Steiner tractor parts. Part #ACS281. $16.

 

[DoubleO7]

Steiner tractor parts. Part #ACS281. $16.

NO
Steiner calls it a cam lock bolt.
says it is a rim clamp bolt for eccentric style rim clamp.

 

[Jim.ME]

Allis Chalmers part number 70218385. Web search using that part number.

 

[Richard Nixon]

Allis Chalmers part number 70218385. Web search using that part number.

View attachment 90922

I used to buy mine at a local hardware store. They were shoulder bolts for kids coaster wagons. That store is long out of business and I sold my Allis.

 

[cleddy]

I have a 1952 WD45 and cannot keep a PTO shear bolt in place. I've tried different bolts including a Grade 8 bolt but they always break within several minutes. The PTO unit seal was replaced last year if that makes any difference. The brush hog works well before the bolt breaks. Any ideas?

Don't you have a slip clutch on your mower?? I use a plain old 7/16" or 1/2" bolt and the hole is not perfect after all these years. We have never sheared one off in my 60 years of being involved with two tractors?

 

[Brian B Glynn]

As Joe said, all the holes that the shear bolts goes thru need to be round and as close to the same size as the shear bolt as possible.
Any wallowing or elongation of the holes allows the two pieces to hammer the bolt until it shears.

The hole has become slightly elongated.

 

[Brian B Glynn]

The hole is slightly elongated and I do use a slip clutch. Could the slip clutch be bad?

 

[DoubleO7]

The hole is slightly elongated and I do use a slip clutch. Could the slip clutch be bad?

Are you running a slip/over-running type cluth on the pto shaft to the mower? (Beyond the pto output shaft of the tractor itself)

Similar to this:

Sometimes they get gummed up and/or rusty and are basically not slipping when they are supposed to.

Others with experience will chime in on this because the below is only a guesstimate.

Not sure as I do not have one, but I think you can back off the springs that provide the grip to prevent slipping to easily.
Might back it off until it just barely slips to let it turn the tractor side without spinning the hog side to "polish" the sufraces.
Then readjust to turn the hog sufficiently.

 

[Brian B Glynn]

Yes I have an overrun coupler. I'll likely replace it as it's over 10 years old and has sit outside.

 

[DoubleO7]

Yes I have an overrun coupler. I'll likely replace it as it's over 10 years old and has sit outside.

Breaking parts that are not vintage tractor parts is usually cheaper and easier to find or work around.

 

[Jim.ME]

The hole is slightly elongated and I do use a slip clutch. Could the slip clutch be bad?

They can stick solid from setting and will not slip. Do you loosen the slip clutch at the beginning of each year enough to let it slip some? That insures it has not stuck from setting and breaks away rust on the faces. Then tighten back to specs. You can mark the sections to give a visual check to see if it is slipping during operation.

 

[Aaron SEIA]

An overruning clutch is NOT a slip clutch. You need to see if the mower has a slip clutch and verify it actually works. What are you trying to cut that keeps breaking the bolt? The PTO gearbox was a weak spot on a WD. Keep it up and you'll be replacing PTO gears.
AaronSEIA

 

[cleddy]

An overruning clutch is NOT a slip clutch. You need to see if the mower has a slip clutch and verify it actually works. What are you trying to cut that keeps breaking the bolt? The PTO gearbox was a wear spot on a WD. Keep it up and you'll be replacing PTO gears.
AaronSEIA

We have a bushhog mower that was shearing shear bolts on the mower. The multi-disk spring loaded slip clutch was rusted solid. Needed to take it all apart and clean up and then only tighten enough to keep the blade turning good. Mostly broke shear pins blades hit the dirt, rocks or telephone boxes in the grass. After a while you learn not to hit that stuff????