Great Bend 651 Backhoe

[Gene :^)]

I have a 1999 NorTrac NT254 with Great Bend Loader and Backhoe.

While completely overloading the Backhoe trying to break a stump free (I know, I know), the bucket cylinder shaft bent 90 degrees. This is the cylinder that curls/crowds the bucket.

Today I called Northern Tool and was told that Great Bend has been bought out by Bush Hog. Northern Tool had a slightly different cylinder that "should work" for about $500. I wanted the exact cylinder so I called Bush Hog and was quite surprised to find out they want just under $1900 (yes, nineteen hundred) for a replacement cylinder.

So now I am looking into having a new 4140 chrome shaft machined and welded to fit my existing cylinder.

I will also need to source new seals. Any suggestions are welcome.


Thanks,

Gene :^)

PS: Photos of a previous stump, not the culprit that got me this time.

 

[Bob Rooks]

No wonder the Chinese "junk" breaks down.

I can't believe $1,900.00 for that cylinder. :confused2: You probably aren't going to find an exact fit anyway unless you buy OEM or have a rod fabbed.

Did you try Surplus Center - Hydraulic Cylinders Pumps Motors?

 

[Rich Waugh]

I'm with Bob - try Surplus Center or one of the other general hydraulic dealers and get a cylinder with the right diameter and length. You can always have the ends changed to whatever configuration you need in order to fit the hoe. I've changed a few of them myself and it isn't all that tough to do. Even if you had to buy a second cylinder to get the ends the total cost should be under $500, with the welding and cutting.

The most difficult part of the changeover is sometimes the hose fittings - if they have the OEM cylinder specially configured with the fitting nipples in unusual locations. Even that can be changed by a decent welding shop though. Again, I've done that before so a real welder could do it easily enough.

$1900 for that cylinder is worse than ridiculous!

Rich

 

[Diamondpilot]

I want to see a pic of the cylinder now...

I agree, find something and make it work.

Chris

 

[Car Doc]

Try these folks they build GB loaders its near where I live.

I cant speak for them they may not help you these parts may well be made in china and shipped here or there for assembly that seems to be whats going on with attachments here lately.

I hope they will help they may not but its worth a try they will need all the dimensions.

KMW Ltd
198 N US Hwy 281
Great Bend, Kansas 67530
620-793-6725

 

[Gene :^)]

I love my chinese "junk" tractor. The pulling power, traction w/4wd, and torque from the 3 cylinder diesel are tremendous. Everyone I have done work for is amazed at what the little tractor can do. I pull and push just about anything. I drive into and out of the tightest spots and the roughest terrain. I often use my tractor to "unstuck" my neighbors skid steer (those things are dangerous in the mud). I can drive right through several feet deep mud and 4 feet of fresh powder snow. I have NEVER EVER been stuck in this tractor. I have been close but I just use the backhoe or front end loader to help push and I always get out.

I have been reading posts on this site off and on for many years now, I think the people that dislike the Jinma are just people that are not mechanical and not able to troubleshoot and fix little items. Then those little problems seem larger than they really are since you have to bring the tractor to someone to fix it. Or they are people that don't operate it correctly. The power of these tractors is great, but use it wrong and you will find out that it is powerful enough to smash itself to bits. It is all about controlling the power and applying it to whatever you are working on, not reflecting the power back at the tractor. If that last sentence didn't make sense then you will probably not like any compact tractor.

I do all my own repairs but have never broken anything major. I have only had things come lose or get bent. I have replaced gaskets, a belt, and coolant hoses. A few batteries too (FYI: get yourself an Optima, they don't go dead when you let the tractor sit for months at a time, that is what was killing my regular batteries. They slowly discharge on their own and if they sit in a dead state, they stay dead.)

The best thing I ever did was tack weld my clutch arm to the pivot shaft so it quit coming loose, never had to adjust the clutch again and I am on the original clutch from 1999.

Anyhow, back to the task at hand...

The machinist at my work turned down a new shaft for me. I will put it together tonight and weld on the end tomorrow. I'll update on how it goes.

Pictured is the cylinder all apart. I had to cut the bent shaft to get it apart so ignore the cut section. In the picture is the new piece of 4140 shaft ready to be machined. Then a photo of the new shaft getting machined. And for fun, a photo of a different stump leaving the ground.

Gene :^)

 

[Gene :^)]

Forgot to mention: The cylinder is a bit of a strange one. It is a 14 inch stroke by 2 inch bore but only 20 inches eye to eye when closed.

Most cylinders are 12 or 16 inch stroke. Also, most cylinders larger than 12 inch stroke start at 22 inches or more eye to eye.

Ended up being best to just fix what I have so it fits perfectly and my hoses go right on. The paint matches too :^)

Gene :^)

 

[Gene :^)]

Ready for welding tomorrow...

 

[Bob Rooks]

(FYI: get yourself an Optima, they don't go dead when you let the tractor sit for months at a time, that is what was killing my regular batteries. They slowly discharge on their own and if they sit in a dead state, they stay dead.)
With all due respect sir, letting machinery sit idle for "months at a time" is very bad maintenance practice. A more responsible approach is to start and run for 1/2 hour each month during lay up.

The best thing I ever did was tack weld my clutch arm to the pivot shaft so it quit coming loose, never had to adjust the clutch again and I am on the original clutch from 1999.
And now the external pin is no longer the weak link, the shaft or the fork are.

Anyhow, back to the task at hand...

The machinist at my work turned down a new shaft for me. I will put it together tonight and weld on the end tomorrow.
I recommend threading and welding BEFORE assembling the rod, and chroming it.
I wish you succsess in your project.

12345

 

[Gene :^)]

Done!! Well almost done, I still gotta spray some black Rustoleum on the end and bolt up the pin retainers.

Thanks for the support.

Gene :^)

 

[psj12]

What was your cost at the completion of the repair?

 

[Gene :^)]

I got lucky having access to a lathe and welder.

Machine work and welding - free.

The 4140 round bar (hardened, quenched, tempered, chromed, precision ground to -.0015) was $65 plus tax for 3 feet (so I have extra).

Ended up re-using the seals since it didn't leak in the first place and they looked great once I took it apart.

Had a can of black Rust-Oleum laying around - free.

Gene :^)

 

[Diamondpilot]

Done!! Well almost done, I still gotta spray some black Rustoleum on the end and bolt up the pin retainers.

Thanks for the support.

Gene :^)

Very nice job Gene. Glad you and your buddy could get it fixed.

Chris

 

[Bob Rooks]

Excellent! :thumbsup:
Anyone else would be in the hundreds.

 

[RonMar]

Gene, I think you skipped a step... Unless you like this type repair, put in a pressure gauge and check the pressure that your relief valve is opening at. This is one of the kinds of things that happens when the hydraulic pressure gets up too high. Also since the bend was in the same plane as the pivot, this might have been helped along by the pivot at the end of the rod binding. The cylinder is fuly extended, at it's weakest, under heavy load, and that pivot binding, and applying torque/sideload to the shaft, and over she goes headed for pretzel town...

 

[Gene :^)]

The pressure relief is most likely ok. I was really overworking the backhoe.

I had the bucket teeth wedged under the stump and the back side of the bucket against the ground, using all three boom cylinders at the same time to lever the bucket (like a prybar). I also reached back and increased engine RPM to boost the hydraulic flow up faster than the relief could release. There was tremendous force and I was not at all surprised it got bent.

The retaining pins that hold the pivot pin at the bent end of the cylinder were also bent from the pivot pin binding and trying to spin.

Need to grease it right before I use it each time.

Gene :^)

 

[Bob Rooks]

You are absolutely correct Ron, and Gene by his own admission validated one of your scenarios. And Gene knows the full output of the pump (gpm @ r/m & psig rating) and the PRV pop pressure and whether it dumps to zero or maintains set pressure by Telekinesis. I tried that once on my lawnmower as an experiment: was there some oil in the engine or not?

 

[RonMar]

Well Bob, you are way ahead of me, I still must rely on dipsticks and gauges

Gene, if the PRV is sized and set properly, it should be virtually impossible to do what you did, unless the pivot end really bound up and severely side loaded the rod. The bent pin at the pivot also indicates excessive force applied by the cylnder.

On another note, how are the welds/structure around the top corners of the bucketmost stressed part of the bucket structure) holding up? Thru hard use(stumps) I had to rebuild mine...

 

[Gene :^)]

Nortrac NT254 - 1 point

Kubota Excavator - 0 points

See photos and you will see why.

Actually at the end of the day we each trenched 100 ft (200 ft total) at 3.5 feet deep. We had three trenches merge in a "T" shape. My tractor was better at making the trench connections because:

1. I didn't fall into the trench, haha!
2. my backhoe hangs off the back of the tractor so I was sort of cantilevered over the trench at the end when I had to be perpendicular instead of parallel.

My Nortrac righted the excavator with a chain to my FEL, I lifted it right up, then helped pull it out after up righted.

The repaired cylinder on my backhoe worked perfectly. I don't feel the need to check the PRV, it bypasses when I get the bucket stuck but still has enough power when I need it. Good enough for me the last 12 years with only one failure at a time I knew I was being rough on it. Also, I now grease it right before each job, the day I bent it I hadn't greased in a while.

Bob, I can tell the pressure by the swell of the hoses, and the flow by the hissing sound when a cylinder moves fast. Haha.

Ron, The welds and bucket are holding up but I can see the stress spots (the paint comes off too at the stress spots, I guess from the steel flexing or maybe making heat).

Gene :^)

 

[RonMar]

Ron, The welds and bucket are holding up but I can see the stress spots (the paint comes off too at the stress spots, I guess from the steel flexing or maybe making heat).
Gene :^)

Stress and heat will both remove the paint The top of my bucket was put together really poorly, with parts not fitted real well before welding, and the welder used to fill in the gaps. The choice of material used also made it virtually impossible to weld it correctly/fully.

Your pivot pin was probably the main cause of your failure then, but it shouldn't have bent.

One thing I discovered while I had my bucket off for it's overhaul/repair, was that two of the pivot bushings that had grease fittings on them were not drilled. Basically the zerk fitting was screwed into a hole with no outlet. I thought perhaps the bushings had rotated, and blocked off the grease fittings, but inspection on the inside showed that there were no holes at all in the bushings. Quickly fixed, but shame on me for not catching that there was never any grease exiting the sides of the bushings when I hit them with the gun...