410 Hose problem

[telwood]

Straight 410 backhoe

Just as I get other thing fixed and start working again I'm about an hour on the hoe and a hose blows. The hose feeds the backhoe and is about 6" long x 1"id just above the filter housing. I assume this is a pressure line since most of it is steel pipe and this small piece is on the end of the line.

So the hose blows and I replace it and maybe an hour back on the hoe it does it again. Not sure if there is a pressure problem or maybe the fluid is getting to hot but am not sure what the cause could be.

Any ideas.

Thanks,
Tom

 

[Ronsii]

How did it blow? blow end off... blow through rubber and braid wire...

 

[telwood]

The first blow out was on the center at the bottom and blew a hole through the rubber and braided wire.

The new blowout I haven't seen yet but the hose is still attached at both ends. I'll take it off tomorrow morning and see what it looks like.

 

[Delmer]

A 40 year old hose is allowed to blow at any time. It's the new one that matters. There's a fair chance one of the couplings came loose, or the hose was defective to start with.

This doesn't connect to the filter, does it? just near the filter.

 

[Blueboy]

I'm curious to know what your pressure is and what the new hose was rated at. I don't think it's a heat problem. For only an hour run time something would be getting cherry red.

 

[willie59]

A 40 year old hose is allowed to blow at any time. It's the new one that matters. There's a fair chance one of the couplings came loose, or the hose was defective to start with.

This doesn't connect to the filter, does it? just near the filter.

Keep in mind we're talking about a Deere. I don't know what series 410 we're discussing, but most Deere loader/hoes used the Deere load sensing variable displacement pump, closed center system, even if a coupling came loose it shouldn't develop pressure more than the standby pressure metered by the load sensing system. As you stated, a 40 yr old hose can pop without warning, but i if the new hose is proper spec/pressure, and it turns out the hose assy is correct, maybe a problem with pump pressure output??? More in info need for sure.

 

[Delmer]

Willie

He mentioned a 1975 410 in another post, so it should be the closed center system. He didn't know yet where the new hose burst, that's why I thought it might be leaking from a loose fitting, and a half turn loose will let it empty fast at standby pressure.

There was talk about stuttering, plugged screens, etc. so anything is possible. The pressure regulating valve on the hydraulic pump would be getting pulled out if a new hose blew on me like that.

 

[willie59]

Thanks for the info Delmer, I haven't kept up with the info on this machine, it's just when I see Deere loader/hoe I know we're typically looking at a load sensing system, so yes, depending on just what failed on the new hose we may need to do a more in depth investigation.

 

[lantraxco]

The older Deere's, and some not so much older with those radial pumps, used closed center but not load sense, they ran at full pressure standby all the time, from zero flow to whatever the pump would put out.

One place I worked had a 510, with and aux valve for a hammer. One of the pressure lines for whatever reason ran over top of the valve stack just under the sheet metal cover for the control sticks. At wide open throttle running the hammer, the operator let up on the foot switch, the solenoid valve snapped shut and with the pressure spike that hose blew out... dumped roughly 25 gallons of hot oil in about ten seconds... if he hadn't had fast reflexes and his rain gear on, he would have ended up in the burn unit, or worse. Word to the wise, on this type system, if you develop a hole, the pump will try to fill it at full pressure until you get it switched off or it runs out of oil, whichever happens first.

 

[Blueboy]

By the way, PLEASE keep your hands and every part of your body away from the hydraulic lines and hoses. Oil injection will get you a trip to the hospital ! ! !

 

[lantraxco]

Blueboy, you are correct. I have seen pictures of injection injuries, the aftermath of several surgeries to remove the fluid and dying flesh. It's a long painful process to recover from even a small wound like that and fatalities do occur. One field mechanic I used to see several times a week actually lost the last joint of one finger from having it in the way as he was tightening bolts with an air wrench. Don't recall if it was Loctite or silicone but the force of the bolt squeezing out the liquid injected it under the skin and after fighting it for a couple weeks they ended up removing part of his finger to prevent any further loss. Scary.

 

[hosspuller]

I know about the danger but never thought much about it ... Not anymore ..

according to the Fluid Power Safety Institute, “Over 99 percent of the people who service, repair, and troubleshoot hydraulic systems have been subject to the exact dynamics that trigger a high-pressure injection injury. However, the ‘liquid bullet’ either missed or deflected off its target.”

click this link to understand ... http://www.constructionequipment.com/injection

 

[lantraxco]

Not sure what you're saying here, do you mean to say since most of us dodge the bullet we shouldn't worry about it?

 

[hosspuller]

Not sure what you're saying here, do you mean to say since most of us dodge the bullet we shouldn't worry about it?

Au contraire ... because most of us have dodged the bullet, The danger is not always apparent. (I used to work with 10,000 PSI process feed pumps too. I stupidly touched a leaking fitting. Missed me that time. ) Google "injection injuries" for grusome pictures of the result.

 

[willie59]

The older Deere's, and some not so much older with those radial pumps, used closed center but not load sense, they ran at full pressure standby all the time, from zero flow to whatever the pump would put out.

And you would be correct, I was using the term load sense in a generic sense, they don't have an external load sense line from the valves, rather the Deere pumps internally sense changes in demand from the system and produce output (flow) according to demand, standby pressure would be whatever that particular model was designed to be. I once worked on a new Versalift bucket truck with a Rexroth hydrostat pump and was surprised they had standby pressure at 3000 psi. I mean, yeah, sure, it can work that way, but why design a hydro system to have such high stress (pressure) on the hoses at all times. Oh well...I don't build this stuff.

 

[telwood]

I removed the new (2nd) piece of hose (2.25" long x 1"ID) and it appears one end blew off since I saw no obvious damage. I'm going to get a heavier hose and heavy duty clamps and try it one more time before looking elsewhere. The first hose had an obvious blow so now I'm confused until I try it one more time. The bad part is I used the backhoe a lot digging stumps last Winter with the first hose so I feel something has changed. One hour on the hoe at a time won't cut it.

I am no mechanic (a weekend farmer) and have no access to testing the pressure. The hoe worked great right up until the hydraulic fluid drained out...both times.

 

[willie59]

Whoa, wait, what? Clamps? I sure wish I new what hose we were working on here, but if it's a pressure hose, that's not an application for clamps. :beatsme

 

[telwood]

"There was talk about stuttering, plugged screens, etc. so anything is possible. The pressure regulating valve on the hydraulic pump would be getting pulled out if a new hose blew on me like that."

Thanks Delmer: I seem to have resolved lots of other stuff and after I make 100% sure this small hose replacement doesn't work with the heavy hose and clamps I'll go to the pressure regulating valve.

 

[Delmer]

Back up. 2 inches long, 1 inch diameter and held on with some kind of clamp? Is that the same as the old hose that came off?

And does this hose connect to the filter or not? Does it connect the valve to the pump or the filter?

 

[Blueboy]

Can you post some pics?