Cylinder rod moral question

[BrianGrenier]

The local hydraulic expert in response to my question about a weak thumb on an excavator said that I could remove the pressure relief valve. Well I did so, had the ram extended, overextended, was bleeding and pushed thumb back with the bucket and bent the cylinder rod.

So if I had the advice from the expert and I told him I really didn't know hydraulics (Now I know the pressure relief sends oil back to the tank in case of pressure situations) what is his responsibility for repair?

 

[BrianGrenier]

 

[Heavey Metal]

Main relief

Or circuit relief?

 

[lantraxco]

Ouch. Morally it's my opinion he owes you the repair. Legally may be another subject.

 

[Delmer]

Um, is he on retainer? do you have a service contract with him? how much did you pay for the fine advice? I'm thinking the answer is no, nada, zero...

Only advice I can give is don't retract that cylinder, take it off and fix it before it ruins the rest of the cylinder. It MIGHT be straightenable. But don't ask me to pay for it if you drop it on your toe cause you don't know how gravity works

 

[kshansen]

Um, is he on retainer? do you have a service contract with him? how much did you pay for the fine advice? I'm thinking the answer is no, nada, zero...

Only advice I can give is don't retract that cylinder, take it off and fix it before it ruins the rest of the cylinder. It MIGHT be straightenable. But don't ask me to pay for it if you drop it on your toe cause you don't know how gravity works

Would have to side with Delmer on this one. He may have made a mistake saying what he did but also might have thought he was telling you how to test something to isolate a problem, not how to set it up to actually be used.

Kind of like if you had asked someone how to get a small riding lawn mower to start and the told you to disconnect the safety switches. You do that and it starts up just fine.

Then you went ahead and let someone borrow it to mow their lawn and they end up getting hurt when it takes off in gear and runs over their foot. You then expect the guy to pay the hospital bills for the other guys injuries.

 

[Cmark]

I fail to see how removing a relief valve can, presumably, dead head a cylinder. Further I can't see how you can bend the rod by pushing it in unless there's something strange about the geometry of the setup.

I would be curious to see a bigger picture of the machine.

 

[Jonas302]

None Zero zip no responsibility at all Morally or otherwise

 

[movindirt]

I'd like to see a picture of the whole thumb before I comment any further

 

[td25c]

From a moral standpoint the hydro thumb arrangement on the hoe wasn't built tough enough for the application

Somebody failed in the design or mounting of the thumb , like mentioned bad geometry or simply not enough metal where it needs to be ( bigger cylinder) to match curling cylinder power from the bucket .

Good news is the cylinder can be repaired .

 

[big ben]

When a thumb is extended all the way out and you curl the bucket back in against it i can see them bending like this. The thumb cylinder is parallel with the stick and the bucket when it curls is pushing perpendicular to the stick so I can see this happening no problem when the reliefs are removed.

Thumb cylinder rods are long and usually not a big diameter

 

[lantraxco]

Relief valves are installed for a reason, ANYBODY that tells you to remove a relief valve from a circuit, if that's what actually transpired, is most likely criminally negligent in doing so. Telling you to adjust up or replace with a higher pressure relief may be acceptable.

 

[Cmark]

It all depends on what's meant by "removing a relief valve". I had in mind a cartridge valve unscrewed from a valve block in which case the cylinder wouldn't work at all. Could it have been an independent in line valve that's been removed?

I've never seen an excavator without cartridge line relief valves on the auxiliary circuit.

 

[Nige]

Thumb cylinders are generally not the strongest thing in the world and that's why they have relief valves in the circuit so that when the bucket curls round it doesn't bend the thumb cylinder rod or worse still break the thumb cylinder mount clean off the stick. If the OP removed the pressure relief function to the thumb cylinder he should not be surprised if the cylinder rod turns into a banana IMHO.

 

[oarwhat]

While he's not legally responsible I would think he should repair it at a heavy discount.

 

[CM1995]

Did the one you received the advice from install the thumb?

 

[Jonas302]

The thing is there a many "Experts" around some truly know there stuff some we just assume must know the answer to every question because they work at the hydraulic repair shop Sometimes we ask different experts until we find the answer that we like. One thing is for sure the manufacture of the machine was not contacted and told you to remove or bypass a circuit protection devise that they designed

One has to sort all the advice given and use your own judgement even on the internet full of experts as you are the one putting the wrench to it as some would say if you have to ask you shouldn't be messing with it

Even given the poor advise followed the operator bent the cylinder pushing back on it with the bucket

 

[Willie B]

I did that with the pressure relief working properly. Pressure relief prevents the pump from supplying too much oil (or oil pressure) to the cylinder. It is not designed to receive a large volume of oil back to the reservoir. A thumb needs a bypass valve. It moves pressure from one side of the piston to the other. Mine is a small block of steel with four ports for hoses, and an adjuster.

It is incumbent on you to sort advice. Does this make sense. Did he fully understand my question. I will counter that turning up the relief valve likely didn't cause your problem. The lack of a bypass valve did.

If I told you to solve a tripping circuit breaker by bypassing the breaker, I hope you'd wonder if it'll work better without, why is it there in the first place.

Willie

 

[BrianGrenier]

Main relief
Or circuit relief?

Circuit relief I guess. Understood that I am just learning about hydraulics

 

[BrianGrenier]

Um, is he on retainer? do you have a service contract with him? how much did you pay for the fine advice? I'm thinking the answer is no, nada, zeros

No retainer no service contract free advice just helping me with hoses and why the thumb was weak. There was a question about the pressure relief valve working that he answered and suggested it could be the problem and remove it from the circuit as it was not doing anything possibly

Took your advice and removed the cylinder the service guy says that he knows someone with a press that can straighten possibly most likely good cheap fast pick two good and cheap