Hydraulic Rupture #2

[txdon]

Egon, That was the line that was repaired before. There could have been a negative effect from the heat of the first repair since it was so close.

<font color="blue"> "Hydraulic system should be designed for any pressure the unit may be subjected to." </font>

I agree with you (that's why I conversed with Kubota on the first rupture) the hydraulic system should be designed to handle this with some relief valve in the system.

Does anyone know if it is feasible to install an in-line relief valve or warning signal - or would this cause some negative FEL operations/conditions. Of course I will check with Kubota also, if TBN can not find fault with it.

 

[Scrounger]

Rat could you mount a guard like that on the smaller sub-cuts like the BX? I think it would be a nice add-on for anyone who uses the bucket alot.

 

[tractorman]

Kubota has had a problem with weak hydraulic tubing. We have replaced half a dozen or so on late model front end loaders. Newer, heavier lines are available at your local dealer.

 

[_RaT_]

"Hydraulic system should be designed for any pressure the unit may be subjected to."

You could, but you would have hoses rated at over 10,000 PSI, cylinders and their seals the same. Taking a bucket so that when the front lip hits a immovable object and is angled such that the full mass of the tractor amplifies the pressure of the fluid against the piston along with the leverage of the four bar linkage, pressures will escalate beyond what many things can handle, even industrials. The best way is simply not to be putting the loader into that configuration.

 

[txdon]

<font color="blue"> "The best way is simply not to be putting the loader into that configuration." - RaT </font>

You are right. NO Bulldozing. In fact the owners manual says:
"Do not use the bucket in the dumped position for bulldozing . As shown above this method will impose severe shock loads on the dump-linkage, the bucket cylinders, and the tractor."

I found the above quote in the area that discuss Backfilling but I proved it also is incorrect to use it tilted to push brush.

I also found on page 2, #38 "Never lift or pull any load from any point of the loader with a chain, rope, or cable. Doing so could cause a roll over or serious damage to the loader"

Does this include things we attach to our non-factory added hooks on our loaders?

 

[Egon]

Seems I've seen many operators on large industrial machines use the bucket like a bulldozer. This is exspecially true when cleaning parking lots with the front wheels off the ground.

My little B7100 spends much of it's time in the bulldozer mode with the front wheels off the ground.

A good design also incorporates internal PSV'S.

Egon

 

[_RaT_]

I always use the bulldozer method, I just don't have it where if I catch something on the front lip like a buried boulder or stump it will leverage the bucket and create the shock load. The way you avoid it is to make sure your not in a dump configuration. To do so is asking trouble. This applies to all tractors with loaders.

 

[WhiteRock]

Are you thinking about putting a relief valve on for both directions of the cylinder?

Where would the PRV dump to?

What pressure would you choose?

I am not convinced this is a good idea.

 

[_RaT_]

"What pressure would you choose?"


That indeed is the question. I suppose that the duration is also a consideration. After all, a 100 watt light bulb draws many thousands of amps while the filament heats up thus increasing resistance. It all takes but a fraction of a second. How much can a hydraulic line take for 1/100,000, 1/1000, or 1/10th of a second?

I don't believe it as much of an issue as one might think, but indeed, bursting a hydraulic line does happen from this very scenario. Common sense would tell me that it would be the dump circuit that would take the brunt punishment of such loader use.

PS, I see my gauge quickly peg at 5000 PSI from back dragging where no immoveable object is easily encountered resulting in the entire tractors inertia and mass forcing a hydraulic cylinder into this sceanario. I have had a few occasions where I have done what TxDon has done and felt the resulting "spring" from the pressure build up. It makes me think what the pressures could be if my gauge quickly pegs at 5000 PSI from light weight back dragging. My guess is many thousands of PSI, well in excess of 5000 PSI.

 

[Dr_Zinj]

Hydraulic hoses should fail before the metal hydraulic lines. If the metal one failed, it was either defective, or the wrong line.

I bulldoze and back drag with my loader.

Backdragging is usually done with the loader in float mode, so unless you have the bucket tilted down more than 45 degrees, you should just bump over any obstructions going backwards.

I use the loader in float mode when bulldozing snow. Just have to make sure the bucket is level, and I remember where all the rocks sticking up in the dirt drive are; that's not a problem as I put markers for them in before the frost.

I also bulldoze soil with the loader. The key is to go slow, plane off just an inch or so per pass, and never pop the front wheels off the ground more than a couple of inches if you hit one of those pesky boulders we grow in New Hampshire. I've been disassembling a rock "wall" the builders shoved off the side of the drive and mixed a bunch of soil with. Since it's set up over the past decade, I'll move up to the end of it and use the bucket tilt in both directions to loosen up the rocks and dirt, and then backdrag the loose stuff a bit before scooping it up. If I'm grading, then I use the backblade for the the angle and tilt to move the fill properly.