Kioti Backhoe is not a JD310
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Coyote machine
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- 22 SANY SY 50U, '10 Kioti DK 40se/hst KL-401 FEL, loaded tires, KB-2485 bhoe, Tuffline TB160 BB, Woods QA forks, MIE Hydraulic bhoe thumb & ripper tooth, Igland 4001 winch, & GR-20 Log Grapple. Woods BBX72" Brush Mower. Diamondplate aluminum canopy
I'm not clear on what you're saying about a JD 310? and Woods hoe, and having 'another serious metal problem' with a KB-2485. Those are what look like some serious stress related breaks, and there is rust in several of the pics, of the orange bar between the outriggers, and in the sub-frame holes too.
Please give details as to how old the hoe and tractor are, how many hours on each, etc. How did the breaks occur, etc.? Not being critical- just needing more details to figure out what/why...
4570Man
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A Kubota BH-90 isn’t a JD310 either so I got rid of it and bought one! 
swnoel
Silver Member
Bought mine in 2004 but haven't abused it much... certainly doesn't have the issues you have. I take it you bought it used? If I had to do it over again I'd opt for a small excavator.
Egon
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Don’t know for sure but the cylinder looks like an inadequate weld. The two steel members might be some very low quality steel that was brittle or undersized?
Rock Crawler
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My professional opinions based on limited information provided in photos.
IGSCC = Intergranular stress corrosion cracking (IGSCC) is a type of corrosion due to applied forces on the granular boundaries of a material; the molecular material that exists on the boundary is more susceptible than the internally placed molecules. (Stress related cracking/failure)
IGSCC on the orange square tube is my bet, you would need to get a micro view to verify. The location is at the toe of weld, heat effected zone, and at the point of concentrated high stress. Remove the stress or upgrade the material/design. Grind out defect, full pen weld, plate over, consider additional material but know that being that tube thickness is likely less than ideal... you will most likely change the location of the stress concentration to the end of your plate/gusset area and move failure down the line. Also note the weld start/stop at the corner of the tube. This creates a likely failure initiation point at the high stress corner combined with that start/stop.
The ram is a bad weld. Weld should not break in the weld unless it has inherent flaws, it should have torn base material away if the weld were not a flawed specimen. While I can not see porosity or inclusions in the visible part of the broken weld, I would really expect that something existed to create the origin for the fault line in the casting (weld). Remove all defective weld material, pre-heat and re-weld.
The plate steel is also most likely intergranular stress cracking, grind it out, full pen weld it, flat top it, plate it.
IGSCC = Intergranular stress corrosion cracking (IGSCC) is a type of corrosion due to applied forces on the granular boundaries of a material; the molecular material that exists on the boundary is more susceptible than the internally placed molecules. (Stress related cracking/failure)
IGSCC on the orange square tube is my bet, you would need to get a micro view to verify. The location is at the toe of weld, heat effected zone, and at the point of concentrated high stress. Remove the stress or upgrade the material/design. Grind out defect, full pen weld, plate over, consider additional material but know that being that tube thickness is likely less than ideal... you will most likely change the location of the stress concentration to the end of your plate/gusset area and move failure down the line. Also note the weld start/stop at the corner of the tube. This creates a likely failure initiation point at the high stress corner combined with that start/stop.
The ram is a bad weld. Weld should not break in the weld unless it has inherent flaws, it should have torn base material away if the weld were not a flawed specimen. While I can not see porosity or inclusions in the visible part of the broken weld, I would really expect that something existed to create the origin for the fault line in the casting (weld). Remove all defective weld material, pre-heat and re-weld.
The plate steel is also most likely intergranular stress cracking, grind it out, full pen weld it, flat top it, plate it.
Last edited:
CPTKILLER
Silver Member
When I was maintenance director in Louisiana at a industrial airport we went through a of equipment cracks or fractures. The most common was on the deck of a Brush Hog Mower. We mowed the airfield 5 days a week all day no doubt stressed it. It was repaired several times.
We had frame cracks on a Bobcat Skidsteer that was used with a hydraulic hammer to break concrete 90% of the time. The repetitive stress from the hammer required serious repair.
My assumption is that most of the manufacturers use the same grade of steel. As a result cracks or metal fractures are a way of life.
We had frame cracks on a Bobcat Skidsteer that was used with a hydraulic hammer to break concrete 90% of the time. The repetitive stress from the hammer required serious repair.
My assumption is that most of the manufacturers use the same grade of steel. As a result cracks or metal fractures are a way of life.
Coyote Machine:
The reference to a JD310 was that the Kioti backhoe is a light duty attachment, not a purpose built backhoe.
The tractor/backhoe has 850 hours. Purchased in 2007. Single owner/operator. Garage kept except for 8 months in 2007/2008. The tractor has been problem free since purchase except for a 4-way flasher solenoid that I need to locate and replace.
I believe the breaks are all the result of my abuse.
Cylinder weld: Fully extended and curling with the bucket cylinder.
Sub frame: Lifting the back of the tractor with the backhoe.
Lower Bar: Digging & lifting with the boom fully on the right side.
The Machine shop welded the breaks and added additional 1/2-inch support under the lower bar.
I was somewhat embarrassed at the machine shop and they told me that it was "normal". They repair cracks and breaks almost every day for all brands including full size JD and Case excavators.
Swnoel:
I agree, an excavator is much better suited to removing stumps and rocks, but I needed to use a box scraper, rotor tiller, post hole digger and rear blade. If I had the money and a place to store it, I would have bought both.
Egon:
Regarding the cylinder weld, the machine shop said the same thing. Regarding the steel members being undersized, the machine shop said the same thing, and added addition support.
Rock Crawler:
Stress & cracking. You are way over my head, but I think you are right. The machine shop explained that the area around the weld was more brittle due to the heating when welded, and was most susceptible to cracking/breaking. Also it didn't help that I abused it. I will try to avoid a repeat performance by not digging on the side in the future.
Cylinder Ram - bad weld. I was not there to see if they removed the original weld material, but the machine shop agreed with you that it was a bad weld to begin with.
CPTKILLER:
That is exactly what the people at the machine shop said.... it is normal.... it happens to everyone who uses the equipment.... They also said “you will be back”.
The reference to a JD310 was that the Kioti backhoe is a light duty attachment, not a purpose built backhoe.
The tractor/backhoe has 850 hours. Purchased in 2007. Single owner/operator. Garage kept except for 8 months in 2007/2008. The tractor has been problem free since purchase except for a 4-way flasher solenoid that I need to locate and replace.
I believe the breaks are all the result of my abuse.
Cylinder weld: Fully extended and curling with the bucket cylinder.
Sub frame: Lifting the back of the tractor with the backhoe.
Lower Bar: Digging & lifting with the boom fully on the right side.
The Machine shop welded the breaks and added additional 1/2-inch support under the lower bar.
I was somewhat embarrassed at the machine shop and they told me that it was "normal". They repair cracks and breaks almost every day for all brands including full size JD and Case excavators.
Swnoel:
I agree, an excavator is much better suited to removing stumps and rocks, but I needed to use a box scraper, rotor tiller, post hole digger and rear blade. If I had the money and a place to store it, I would have bought both.
Egon:
Regarding the cylinder weld, the machine shop said the same thing. Regarding the steel members being undersized, the machine shop said the same thing, and added addition support.
Rock Crawler:
Stress & cracking. You are way over my head, but I think you are right. The machine shop explained that the area around the weld was more brittle due to the heating when welded, and was most susceptible to cracking/breaking. Also it didn't help that I abused it. I will try to avoid a repeat performance by not digging on the side in the future.
Cylinder Ram - bad weld. I was not there to see if they removed the original weld material, but the machine shop agreed with you that it was a bad weld to begin with.
CPTKILLER:
That is exactly what the people at the machine shop said.... it is normal.... it happens to everyone who uses the equipment.... They also said “you will be back”.