Great Bend 651 Backhoe
- Thread starter Gene :^)
- Start date
- Views: 23408
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 :^)
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
Super Star Member
- Joined
- Jan 18, 2007
- Messages
- 16,316
- Location
- Daleville, IN
- Tractor
- Jinma 254/284 Ford 861 Powermaster at work
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
Elite Member
Excellent! :thumbsup:
Anyone else would be in the hundreds.
Anyone else would be in the hundreds.
RonMar
Elite Member
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...
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 :^)
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
Elite Member
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
Elite Member
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, 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...
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 :^)
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 :^)
Last edited:
RonMar
Elite Member
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...