The dangers of backdragging - broken curl cylinder

[jnyost]

While a lot of operators may know the dangers of back-dragging, there are many that do not, so I’m hoping this may help prevent expensive damage and repairs.

The issue with back dragging comes when you have the bucket vertical or even pointed back towards the tires. If you look at the mechanics of the curl function you will see that any pressure on the bottom edge of your bucket is transferred into trying to push the rod back in the cylinder. If the forces are too great the rod has nowhere to go and can easily bend. This damage usually happens when driving backwards too fast or if the bucket catches something immovable. The problem is common upon all brands and sizes of equipment.

While the following story is not technically back dragging, I did damage my tractor and bent a curl cylinder by trying to spin a tree that was cut. I was using forks, put them on the far side of the tree, backed up, and bam, a bent curl cylinder. I wasn’t backing up fast, I didn’t have to force it, yet it still bent.

 

[edritchey]

Good post and great information it's something we all do and get away with most of the time.

 

[mcfarmall]

Yup. I try to make sure the curl cylinder is no more than 1/2 way extended during back grading and even then I'm careful not to use too much down force on the bucket.


Better yet but not as effective is to do the dirt moving with the back of the bucket instead of the lip...but like I said, not as effective.

Best solution would be to swap out the bucket for a fixed dozer blade, not the angle type snow blade. Had one like this on an old Ford tractor and you could make a smooth surface back and forth with no worries.

 

[jnyost]

Yup. I try to make sure the curl cylinder is no more than 1/2 way extended during back grading and even then I'm careful not to use too much down force on the bucket.


Better yet but not as effective is to do the dirt moving with the back of the bucket instead of the lip...but like I said, not as effective.

Best solution would be to swap out the bucket for a fixed dozer blade, not the angle type snow blade. Had one like this on an old Ford tractor and you could make a smooth surface back and forth with no worries.

I have the snow blade for my RTV and it’s the same as the ones that connect to the tractors. I’ve thought about buying the plow subframe so I could use it on the tractor. It has locks on it so it can be used as a dozer blade and not roll with the springs. I know they make blades for the SSQA but I hate the thought of putting lateral stresses on the loader arms.

 

[Lil Foot]

One of the few advantages of having an old tractor- the old style bucket has a round back; curl the bucket all the way up, back drag, and the round back acts acts like a butter knife to spread, smooth, & pack. Virtually no way to hook the bucket on something. Plus, it holds more volume than new angular style buckets of the same width.

 

[twomany]

I dug up the user's manual for the Allied loader on the Hurlimann.
Right there in black and white on one of the pages was written directions to ONLY back drag with the bucket in full curled up. Never with the bucket curled down.

Jeesh!~ The things they don't think of right at the factory. ;-)

 

[sheepfarmer]

So I have been wondering for a while about this issue...the grading contractor that created the pad where my new pole barn sits moved an awful lot of dirt around with a tractor with loader and backhoe. Pretty good size. When a pile was mostly distributed, he smoothed things out by back blading. The bucket tip was angled a little below horizontal, and he put enough down pressure to lift the front wheels off the ground and then backed up. I take it from this discussion that I shouldn't try to copy his technique. What's different about his rig and ours besides color and size? I can't see this guy abusing his equipment.

 

[North Idaho Wolfman]

So I have been wondering for a while about this issue...the grading contractor that created the pad where my new pole barn sits moved an awful lot of dirt around with a tractor with loader and backhoe. Pretty good size. When a pile was mostly distributed, he smoothed things out by back blading. The bucket tip was angled a little below horizontal, and he put enough down pressure to lift the front wheels off the ground and then backed up. I take it from this discussion that I shouldn't try to copy his technique. What's different about his rig and ours besides color and size? I can't see this guy abusing his equipment.

No angled down is fine, it's angled back that will get you into trouble.

With the tip pointed forward and down the cylinder is still mostly retracted.
With the tip pointed towards the tractor is when the cylinder is full extended and very vulnerable.

 

[D2Cat]

Take a look at about 1:13 you'll SEE what North Idaho Wolfman is explaining.

https://www.youtube.com/watch?v=FOS2IZGOGoI

 

[sheepfarmer]

Ah so...Thank you. I don't think mine goes back that far, or at least I've never asked it to in that position. That's good, I kind of like mine un-curled just enough to so I can see the edge of the blade. Granted I don't move much other than bark or horse manure, so not too heavy.

 

[RCW]

Some common sense goes a long way, but a person new to tractors or powered equipment may not realize their machine isn't bulletproof...

I have pulled loose material with the bucket fully-dumped, in float, and very carefully. Otherwise, back dragging is done with the teeth/leading bucket edge pointing forward. The BXPanded toothbar has a good bottom edge for smoothing..

With his video, the OP may avoid other folks doing the same thing.

Good for him!

 

[jryser]

Ok I’ve been doing something correctly when Back dragging. I’m sure there would or could be a time where I wouldn’t; thank you to the OP for making the video - it will save a lot of us a similar headache.


Sent from my iPhone using Tapatalk

 

[jnyost]

Some common sense goes a long way, but a person new to tractors or powered equipment may not realize their machine isn't bulletproof...

I have pulled loose material with the bucket fully-dumped, in float, and very carefully. Otherwise, back dragging is done with the teeth/leading bucket edge pointing forward. The BXPanded toothbar has a good bottom edge for smoothing..

With his video, the OP may avoid other folks doing the same thing.

Good for him!

Ok I’ve been doing something correctly when Back dragging. I’m sure there would or could be a time where I wouldn’t; thank you to the OP for making the video - it will save a lot of us a similar headache.


Sent from my iPhone using Tapatalk

Thanks!! That’s what I was hoping for. If this saves other people from the same damage then it was worth it.

 

[jnyost]

One of the few advantages of having an old tractor- the old style bucket has a round back; curl the bucket all the way up, back drag, and the round back acts acts like a butter knife to spread, smooth, & pack. Virtually no way to hook the bucket on something. Plus, it holds more volume than new angular style buckets of the same width.

The back of my buckets are angled and work decent for back dragging also. It doesn’t work well for packed material. I do use it that was in float sometimes.

 

[jnyost]

Ah so...Thank you. I don't think mine goes back that far, or at least I've never asked it to in that position. That's good, I kind of like mine un-curled just enough to so I can see the edge of the blade. Granted I don't move much other than bark or horse manure, so not too heavy.

Basically you don’t want it curled forward enough that your cylinder is fully, or close to fully, extended. A little tilted forward is fine. Anything pointed straight down or backwards is too far and increases the risk.

 

[mcfarmall]

The mechanical engineer in me tends to think that any extension beyond 50% would increase the risk of bending and the risk of bending would be greater (either linear or exponential) as you continue to extend beyond 50% and approach 100%.

 

[jnyost]

The mechanical engineer in me tends to think that any extension beyond 50% would increase the risk of bending and the risk of bending would be greater (either linear or exponential) as you continue to extend beyond 50% and approach 100%.

I would agree. It’s amazing how many people do not understand the physics. You should read some of the comments on my video. Flat out mean and negative. Most of them are saying it’s because Kubota is junk, or the tractor is too small, etc.

 

[jnyost]

Actually, if anyone is willing to help and come to my defense, please post some positive comments on the video and maybe even hit the like button. Or post some rebuttals to the negative comments.

Getting so much negativity towards Kubota. I don’t understand.

 

[mcfarmall]

Here's a noteworthy thought...ever look at the curl mechanism on a large wheel loader?

They typically have a single large bore cylinder that it coupled to, for lack of a better description, a Z-shaped linkage in such a manner that extending the cylinder is what curls the bucket back and fully retracted is what dumps the bucket.

This arrangement allows for maximum hydraulic force to scoop up material from a pile and maximum strength for the cylinder when back-grading and dumping.

 

[jnyost]

Here's a noteworthy thought...ever look at the curl mechanism on a large wheel loader?

They typically have a single large bore cylinder that it coupled to, for lack of a better description, a Z-shaped linkage in such a manner that extending the cylinder is what curls the bucket back and fully retracted is what dumps the bucket.

This arrangement allows for maximum hydraulic force to scoop up material from a pile and maximum strength for the cylinder when back-grading and dumping.

Yes I have. I was actually at the gravel pit a couple weeks ago and looked closely. I knew they had one large one but didn’t know how it attached until I looked. I think one large oversized cylinder would help regardless.