Cylinder internal leak?

[ovrszd]

Wouldnt hurt to test the cylinder. but if you are getting full system pressure I am gonna assume the machine is just weaker than you expect compared to a mini-ex.

I too am curious as to what model the hoe is....and maybe some pics? Maybe the bucket is too big to be effective in the material you are digging, or someones home-brew repair in the past and put on a different (smaller) cylinder.

Also, some of them old hoe's have different pin holes on the bucket for different leverage and range of motion. One will give more articulation but less power, the other will give more power but less articulation

My 555A has two pin holes. I run it in what would be the weakest hole just to minimize stress. I get more range of movement but less force. It still scoops fine. But in this case, might be worth changing to see results?

 

[sony224422]

Is changing the pins a huge difference? I only ask because mine is very much seized, and beating it and using a puller will not budge the pin more than a few inches. The bushing started coming out with it. That may be a project for another time.

I did go out and practice a bit, I can see how the method described works better. I was able to dig out a decent-sized rock. I think there's a perfect combo of things happening right now- The ground had a ton of rocks and possible ledge, the tractor isn't as powerful as what I'm used to, and I don't really know how to do it.. yet!

One other question I had though is, regards to the bucket size. I will take a picture of the measurements. Looking over the bucket, I can see this poor machine was abused from all the welds on the arm and bucket pivot points

 

[ovrszd]

Changing the pin makes a very noticable difference. But not worth the hassle for you. You're operator skills will adjust to what you have.

My bucket has had a hard life too. Don't worry about it. Look at the front lip and around the teeth. If you have cracks or breaks there they should be repaired.

 

[sony224422]

I may have to try to get the pin out, or find a new one

 

[ovrszd]

I'll get some measurements of my bucket. So we can compare leverage.

 

[LD1]

Not sure what you are measuring but none of them make much difference other than the one from the cutting edge to the pivot pin.

Which that measurment seems to be about 32".....

Now you need to know the measurement from the pivot pin where the bucket hooks to the dipper.....out to the pin hole where the cylinder attaches.

IF you want to know the power increase.....just measure the two holes in relation to the bucket pivot.

For example.......if the hole its in now is 8".....and the the other hole is at 12"......thats a 50% increase in potential power.

Now if you want to calculate what that "actually is" at the teeth/cutting edge......the 32" come into play....

In the 8" hole......8/32 = 0.25
In the 12" hole....12/32=0.375

What that means is.....the force of the cylinder times 0.25 or times 0.375 is the approximate curl power of the bucket at the teeth

To know the power of the cylinder.....you already know the pressure. Now you need to know the cylinder diameter. Which just a guess....but probably a 3" inside diameter cylinder.
So....the area of a 3" piston is ~7 sq inches....and at 2000psi that is 14,000 lbs of force.

So in this case, the 8" hole would give you a curl force of ~3750lbs and the 12" hole would curl with ~5250lbs of force.

So that in a nutshell is how you can figure it. Alot of that was just assumptions on my part.....since Im not the one there with a tape measure to take the critical measurements. In the case of your bucket.....measure the pin holes and do the math.....it may only make a 15% difference......or it may make more than a 50% difference. From this side of the computer screen I cannot tell you exactly

 

[ovrszd]

I went and took my measurements on my bucket. Couldn't get any decent pics because it's wadded into the corner of the machine shed.

Tip of tooth to center of pivot pin, mine is 42". Tip of tooth to center of pin where the cylinder power is applied is 47" Would be 50" of I moved the pin to the outer hole on the bucket.

I didn't take any cylinder pin measurements so can't help with that.

His bucket "appears" to have a lot better leverage than mine. But since I can't accurately measure my linkage to the cylinder I can't tell for sure.

And I don't know his cylinder size. And forgot to measure mine.

I don't have any problems with bucket curl. But I totally agree with technique. I depend on boom curl as much or more than bucket curl to fill the bucket. Sometimes you find yourself in a situation where you have to rely on bucket curl more. You just learn to deal with it.

 

[rScotty]

I'm going to go out on a limb here and say I've never seen it, but it it isn't technique then maybe you do have a worn out curl cylinder. It could be that the cylinder is worn in the middle of the range and only seals well internally when the piston gets out toward the ends. You could test it by seeing if the bucket curl has more power just before it bottoms out each way.

Or maybe the pivot pins are corroded. If you disconnect the cylinder from the bucket can you swing the bucket a few inches easily with your hand?

Most backhoes will curl hard enough to slide the outriggers across the ground. All of mine have been that strong - even the little 3pt BH on the old JD. But that doesn't mean that it will curl hard enough to pull out a rock... and certainly not a root. A pine tree rock the size of a loaf of bread or a pine tree root as big as my wrist will repeatedly stall the bucket curl on our JD310SG with a 24" bucket - and that's a decent hoe. Roughly the next size more powerful hoe than the Ford.

BTW, 2000 psi is plenty. Our old JD only has 1250psi - that's stock spec - and it's never had a shortage of hydraulic power.

On the pin location, it makes a difference, but there should still be a lot more power than you are describing either way. If you lay the bucket out flat on the ground pointing away from you and the boom down then no backhoe has the power to curl it that way even in fairly soft dirt. But if you lift the boom up so that the bucket has some advantage and is in the midpoint of the curl then it will be able to rake at least some of it's tooth depth through even fairly hard dirt. Unless the ground is frozen....of course. Frozen ground will stop any backhoe until you can finally scratch down enough to get an edge loose.

good luck,
rScotty

 

[sony224422]

I took some more measurements- hopefully this makes more sense. I also ordered some new hoses and adapters, I hope to get them in soon and try learning more

 

[LD1]

I took some more measurements- hopefully this makes more sense. I also ordered some new hoses and adapters, I hope to get them in soon and try learning more

Still strictly a guess, cause reading a tapemeasure via picture isnt real accurate.

But it looks like the bucket pin holes are @ 11" and 13" and you do have a 3" cylinder it appears.

So simply moving pin holes should be ~18% power increase.

In the current hole you should have ~4800lbs of bucket curl. And swapping holes should be ~5700#

But when the bucket is fully extended and the pins are nearly inline....there is not nearly as much power avaliable. These numbers would roughly be mid-stroke of the bucket.

I still think its a technique and inexperience issue and would encourage you to post a video of you working the hoe, and showing us the scenario/situations in which the bucket wont curl.