SQ480 shear pin didn't shear?

[Ga Kub]

Anyone with a squealer that can tell me what grade gear oil the book calls for?

80w90

Also, if you don't have the manual, Bush Hog has them online here...
http://www.bushhog.com/images/stories/documents/manuals/Squealer.pdf

 

[Deano]

Grade 2....that is what I use in my post hole digger...

 

[ritschner]

If a 1/2 inch bolt is to large, it may be that the unit is sized for a metric bolt. The size may be a 12mm metric. Try a 4.8 or an unstamped metric bolt in the proper length.

 

[bikerdib]

Wow, 80W-90? That seems a little thin to me. I've always run 70W-140 in my shredders before. With the temps being around 100 lately I wonder if 80W-90 is sufficient. BTW, thanks for the link to the manual. I've been searching the internet but haven't been able to find one.

I plan on going to my local tractor shop today to see what kind of shear bolts I can find.

 

[johnrex62]

Wow, 80W-90? That seems a little thin to me. I've always run 70W-140 in my shredders before. With the temps being around 100 lately I wonder if 80W-90 is sufficient. BTW, thanks for the link to the manual. I've been searching the internet but haven't been able to find one.

I plan on going to my local tractor shop today to see what kind of shear bolts I can find.

Good luck if your local shop is a TSC. I hit three of them in the last two weeks (Taylor, Bastrop and Cedar Park) and not a single bolt in stock at any of them. I did have luck finding the right size at Lowes however.

 

[KubieTwo]

All the shredders I've used had shear pins, never had one with a clutch. I assume that a clutch would be obvious? All I see is a bolt (didn't check the head to see what grade but I know I'm getting some grade 2) at the front of the gearbox.

In fact, I read somewhere that a clutch is not available for the SQ480.

Biker, you are correct. I did not look it up, only raised the question of whether it might have one. HOWEVER, on the BushHog site they show the clutch as an option beginning at the 60" with grade 2 shearbolt as only offering for the 42 and 48".

As far as whether they work, there are procedures for checking and adjusting. If not used for an extended period, they can indeed lock up but usually loosening the bolts and loading it will cause it to slip again and it can be readjusted to spec. I don't worry about mine freezing up because I use it all the time. I do check and adjust it every Spring when I do other service on the mower so I know it is doing what it is designed to do.

 

[kevinj]

Well, I finally pulled the shear (I have to laugh at that) bolt. It was a metric 8.8 which is comparable to a grade 5. I have to find a grade 2 bolt that will fit the hole, a half inch is too big; maybe a 7/16. I also found that the e-clip is missing so if I had sheared the bolt, the drive shaft might have done the floppy, floppy. .

So is the yoke free to turn on the shaft or is rusted on??? I have to check my SQ but it seem like there is a grease fitting by the shear bolt.

 

[bikerdib]

So is the yoke free to turn on the shaft or is rusted on??? I have to check my SQ but it seem like there is a grease fitting by the shear bolt.

Yes, it has definitely been kept greased. In fact, I found another problem when I pulled the shear bolt and checked for free movement; it was missing the snap-ring that will hold the yoke on the input shaft in the event of a sheared bolt. Of course the dealer didn't have one in stock and I didn't measure what size I needed before going so now I have to wait for that to come in from BH.

I remember when I was in high school I worked on a ranch. I was using a Terrain King with the lift wings. If I remember correctly, it used a bolt & plate that attached to the end of the input shaft to keep the yoke in place after a shear bolt let go. I didn't notice the retaining bolt had backed out and was lost. I hit a dirt mound and sheared the bolt. By the time I was able to get everything stopped, the drive shaft was destroyed and everything around it was beat to death. Man what a racket...:ashamed::laughing:

KubieTwo; The dealer told me he has a universal clutch that should work but I think I'll just stick with shear bolts. My shredder will sit quite a lot since I just use it on my weekend place in the woods. I only mow there when the grass gets too big to watch for snakes when you walk. A lot of it was waist high this last time when I was mowing. I don't want to try to make a park out of my section of woods. I prefer to leave it natural.

 

[Verticaltrx]

It probably didn't shear because you don't have enough PTO hp to shear it. That has been the case with my 5' bush hog. I use it on my 24hp B3200 and 32hp Ford NAA and in three years of use I have yet to shear a pin. The shear pin is designed to protect the gear box and PTO driveline from being overloaded, not necessarily your tractor. If you are using a small tractor you will kill the engine on the tractor before it will shear the pin. Same thing on my post hole digger, never sheared a pin with either tractor, just kills the engine when it gets bound up. This is fine with me, the tractor driveline is built tough enough to take some abuse so I don't worry about it.

 

[bikerdib]

It probably didn't shear because you don't have enough PTO hp to shear it. That has been the case with my 5' bush hog. I use it on my 24hp B3200 and 32hp Ford NAA and in three years of use I have yet to shear a pin. The shear pin is designed to protect the gear box and PTO driveline from being overloaded, not necessarily your tractor. If you are using a small tractor you will kill the engine on the tractor before it will shear the pin. Same thing on my post hole digger, never sheared a pin with either tractor, just kills the engine when it gets bound up. This is fine with me, the tractor driveline is built tough enough to take some abuse so I don't worry about it.

Yes, I know the PTO HP is less than the shredder gear box is designed for. I think the same gear box from my SQ480 is used on quite a lot bigger shredders (and that's fine with me; I'll probably never have to work on it). I still think that on a severe hit like I experienced the shear bolt should have let go. I wasn't a gradual bog down but it was like the blades hit once or twice and the tractor was dead. That's got to be hard on the engine connecting rods and everything else.

On the B7100 with the TSC line of the King Cutter I had previously, I sheared the bolts on it a couple of times.

I found some #2 bolts that I will use from now on in my Bush Hog.