RonMar
Elite Member
jwnge said:
You give me a solid stump, gravel pile, large rock and a tractor/FEL and I could pretzel just about any loader in a heartbeat thru improper use... They are not bulldozers, they are loaders. The geometry of the structure is all wrong to use the traction force of the tractor to apply force to the blade edge. Loader arms are at a pretty steep angle when the blade is near the ground This puts the lift arms under a tremendous side load(weakest mode) Bulldozer arms by comparison are in compression when the blade is on the ground(stronger mode) and heavily re-enforced for the task.
Dan that is unfortunate, but I have to agree with Greg. The only mechanical cause I see that could possibly account for a second similar failure would be the loader control safety pressure set too high. Did you check the pressure release point of the loader safety valve after the first failure? A valve set to release at too high a pressure could hydraulically work the structure to death and that is probably the weakest point on the structure. If yours has a prince 5200 series valve on it, the safety valve was probably set at the factory for 2000PSI. It was probably set using a common hydraulic oil. If you are still using the chinese fluids, that thicker oil could also effect the safety release pressure applied to the system when the valve opens.
If the max pressure was OK, then I would have to guess that the blade was not parallel to the line of travel when pushing ahead into whatever it was you were pushing against. First rule: Don't apply any more force to the structure than you could apply with the hydraulics while setting stationary.
The hydraulic safety dosn't work unless you are trying to move a load hydraulically. Even if you were working the control, the load check valves in the valve body prevent the fluid from flowing the opposite way of that commanded (load weight overpowering hydraulic pump).
The 254/284 has around 1300 pounds of traction force. If the bucket bottom/edge is not parallel to the line of travel and pointed downward significantly, digging the bucket edge into the ground would be the same load on the curl cylinder and structure as trying to curl that same 1300# at the bucket edge.
The jinma ZL-20 FEL is rated to lift 875# and I would bet that is at the bucket attach pins, not out at the bucket edge. They rate the breakout force at 2200#, but they define that as the "load at which entire system will collapse" I have not looked at many other loader specs, but I doubt there is a loader of this size out there rated to curl 1300+ pounds on the bucket edge, let alone lift it. Trying to lift that much weight out on the bucket edge would lift the rear wheels off the ground on this size tractor anyway. These rateings could also be exceeded by bouncing a heavily loaded bucket over rough terrain by going too fast. That 1300 pounds of traction force is also in creeper gear. Any appreciable forward momentum and you could easilly exceed that much force(ask the gentelman who pretzeled his rear blade on a stump while moveing along too fast).
That being said, I have removed many many stumps with a FEL and I have removed quite a few using this same loader and tractor combination(that is it in my avitar). I took out a large fir tree last weekend and was moveing around chunks of wood on my 30" tine fork bucket that were so heavy, the tractor was light enough in the rear end to not have enough traction to get up the gravel driveway in 2WD(one wheel or the other would loose traction). I was also carefull not to let the load bounce as those accelerations could be devistating to the structure(and the tractor front axle). I don't back and ram with it(nor would I with any FEL) and I only apply loads to the edge of the blade(like slicing cheese with a knife). In the 18 months I have used mine, I have regularly brought the tractor to a halt with the FEL while pushing against immovable objects(with tires trying to dig their way back to their country of origin
. I always do engagement work at a slow bell, because momentum is such a killer.
