Backhoe blowing hoses

[Mace Canute]

Ok, if you say so...

I would think a person would need to have more information before averring that was the problem considering the OP has said nothing about the viscosity of either, which would have the most effect.

 

[wvpolekat]

Ok, if you say so...

I would think a person would need to have more information before averring that was the problem considering the OP has said nothing about the viscosity of either, which would have the most effect.

If you want to advocate randomly swapping fluids and then acting like it couldn't have caused problems that occur immediately afterwords, that's your choice. Next time you change your oil, why don't you try washer fluid instead, it's a lot cheaper. Or, since you obviously think that motor oil and hyd oil interchange, try using it. Let us know how that works out for ya, ok?

Basically ignoring the fact that he openly said he put the wrong fluid in it just before this problem started is foolish. I think you know this, but for some reason want to take me to task on my pointing out what I feel is the most obvious thing in his entire post. No skin off my nose, just don't come anywhere anything of mine that has fluids in it.

 

[J_J]

I believe that Parker hose and others is burst tested to 4X max. Just don't think the pump can build up that much pressure. The control valve probably has a pressure rating somewhere around 3000 to 3500 psi. Dynamic pressure can exceed 5000 psi when a ram is forced by mechanical action. Did you ever blow out a return hose? Check them QD's if in use.

 

[Ford tractor]

Ok, if you say so...

I would think a person would need to have more information before averring that was the problem considering the OP has said nothing about the viscosity of either, which would have the most effect.

True, but it's likely that the original spec was 5w30 and straight weight hydraulic fluid will be 30 to 40 wt equivalent. Possibly higher. It would be
nice if the OP could chime in with the specs for the original motor oil and the exact hydraulic fluid used.

Don't forget that straight weight gets thick MUCH faster than multi-vis motor oil. In the olden days, it was common to add 1 gallon of kero to 4gal of hydraulic fluid in the winter to thin it out.

And yes, different viscosity fluid can change the system pressure due to he reactivity of the relief. More food for thought.

 

[wvpolekat]

I believe that Parker hose and others is burst tested to 4X max. Just don't think the pump can build up that much pressure. The control valve probably has a pressure rating somewhere around 3000 to 3500 psi. Dynamic pressure can exceed 5000 psi when a ram is forced by mechanical action. Did you ever blow out a return hose? Check them QD's if in use.

Bad batch of hose? Badly made hoses?

 

[Jeff Lary]

I agree if it were me i would at least try using Motor Oil like you said it was supposed to have. I might go to wall mart buy cheep motor oil at first and try it, if it seems to work fine then i would drain the cheep and refill with a better grade of oil. That way if you keep blowing hoses it would not be the better grade of oil and if it works, well you are helping to flush the system of the Hyd oil when you replace it with the better grade. Good luck

 

[Mace Canute]

True, but it's likely that the original spec was 5w30 and straight weight hydraulic fluid will be 30 to 40 wt equivalent. Possibly higher. It would be
nice if the OP could chime in with the specs for the original motor oil and the exact hydraulic fluid used.

Don't forget that straight weight gets thick MUCH faster than multi-vis motor oil. In the olden days, it was common to add 1 gallon of kero to 4gal of hydraulic fluid in the winter to thin it out.

And yes, different viscosity fluid can change the system pressure due to he reactivity of the relief. More food for thought.

Exactly! Without knowing what the respective specs are, it's premature to say the hydraulic oil has too high a viscosity. It might very well have an equal or lower viscosity.

 

[pinus]

Guys, I really appreciate the feedback and points made. I should have provided some specs first. Here are some of the details in the manual:

Operating Pressure: 2150 psi
Bucket Digging Force: 2875 lbs.
Dipperstick Digging Force: 1744 lbs.
Oil: 10W40 engine oil with API "SD" classification in Northern climates, SAE 40W in Southern Climates. (I'm in southern Missouri)

I stopped at a local logging equipment shop today to have a new supply hose made. They seemed to think it was a stuck pressure valve...not sure if that is stuck shut or stuck open. Looking at the illustrations in my manual it shows what they call relief cartridges which are non-repairable except for seals...is this what they are speaking of.

Don't mind switching the fluid and filter back as discussed. At least I understand how to do this!

 

[ptexer]

It sounds like some tough digging. Once on my JD 310 I had multiple hoses blowing. I resecured all my hoses to reduce vibration and that fixed my problem.

 

[wrenchturner]

Pressure relief valve has to be sticking. Seen it happen on automobiles.