Hydraulic Cylinder bleeds down time to rebuild

[mcollect]

The tilt on the FEL on my BX2370 bleeds down. I think I will rebuild it myself. Any ideas on how to find out how to go about it. Never worked on hydraulics but can rebuild an engine so this should be simple.

 

[Birdhunter1]

If you are already mechanically inclined go to youtube, as strange as that sounds people use it all the time for such things. Watch a couple different videos and get the jest for what's in a cylinder, what goes bad and what you don't do.
https://www.youtube.com/results?search_query=rebuilding+a+hydraulic+cylinder


This one is very helpful on how to deal with stiff nylon rings, then use a hose clamp with a plastic strip underneath (between the clamp and ring) to make for an even compression when it cools and shrinks.
https://www.youtube.com/watch?v=GCKVxjq_GIA

 

[Fawken]

Just make sure you which cylinder is bad as it could also be the control valve. If it is a cylinder they're so cheap I'd probably just get a new one.

 

[MtnViewRanch]

Before you do anything else, test the cylinder to be sure that the cylinder is the problem and not the control valve. With the bucket level on the ground, unplug the curl circuit hoses. Mark the rod with tape or a felt pin. Raise the bucket and see how far the rod extends after 15 minutes. Next do the same thing, but with the hoses connected again.

See what your results are.

 

[ovrszd]

Before you do anything else, test the cylinder to be sure that the cylinder is the problem and not the control valve. With the bucket level on the ground, unplug the curl circuit hoses. Mark the rod with tape or a felt pin. Raise the bucket and see how far the rod extends after 15 minutes. Next do the same thing, but with the hoses connected again.

See what your results are.

I agree with Brian that it might be the valve rather than the cylinders.

As for testing. I used to be on Brian's side about how to test cylinders. But I've been educated. Can't remember which TBN member helped me with this. If you uncouple the hoses, and you are waiting for the cylinders to extend, this will require the ram seals or couplers to fail and suck air. Not sure that will happen. And if it did, it might not indicate the problem, just might do it because of the pressure exerted in the test.

Hopefully the hydraulic gurus will get on here and help you with a good test. It's above me.

I just "know" that the cylinders cannot extend, even if the cylinder seals are junk, without getting fluid or air from outside the circuit created by uncoupling the hoses.

I'm embarrassed to admit how long it took me to understand that. But I now see the "light". Just don't immediately assume it's the cylinders, cause it might not be.

 

[MtnViewRanch]

I agree with Brian that it might be the valve rather than the cylinders.

As for testing. I used to be on Brian's side about how to test cylinders. But I've been educated. Can't remember which TBN member helped me with this. If you uncouple the hoses, and you are waiting for the cylinders to extend, this will require the ram seals or couplers to fail and suck air. Not sure that will happen. And if it did, it might not indicate the problem, just might do it because of the pressure exerted in the test.

Hopefully the hydraulic gurus will get on here and help you with a good test. It's above me.

I just "know" that the cylinders cannot extend, even if the cylinder seals are junk, without getting fluid or air from outside the circuit created by uncoupling the hoses.

I'm embarrassed to admit how long it took me to understand that. But I now see the "light". Just don't immediately assume it's the cylinders, cause it might not be.

No, the cylinder can not compress, it will extend.

 

[ovrszd]

No, the cylinder can not compress, it will extend.

Yep.

And to extend it has to take in fluid or air from outside the circuit because as it extends it holds more volume of air/fluid. To do that it has to breach the ram seals and suck air from the outside. Unlikely.

So if it doesn't breach the seals, it's proved nothing.

Took me wayyyy longer than I want to admit to understand that. Yeah, I'm slow.

No offense intended Brian.

 

[MtnViewRanch]

Yep.

And to extend it has to take in fluid or air from outside the circuit because as it extends it holds more volume of air/fluid. To do that it has to breach the ram seals and suck air from the outside. Unlikely.

So if it doesn't breach the seals, it's proved nothing.

Took me wayyyy longer than I want to admit to understand that. Yeah, I'm slow.

No offense intended Brian.

No offence taken, the ram will extend. Go back and look at those threads, it was all about compression, not extension. Plenty of room for fluid to move to the closed side of the cylinder, it will not collapse, even without a piston, because there is no place for the fluid to move to. Plenty of room to extend though and if you have a heavy enough load, there will be a vacuum created, seen it, done it, no questions about it.

So according to those hydraulic gurus, it is impossible to test a cylinder and all cylinders should just be rebuilt if there are ever any questions, because, well there is no way to test them.

 

[ovrszd]

No offence taken, the ram will extend. Go back and look at those threads, it was all about compression, not extension. Plenty of room for fluid to move to the closed side of the cylinder, it will not collapse, even without a piston, because there is no place for the fluid to move to. Plenty of room to extend though and if you have a heavy enough load, there will be a vacuum created, seen it, done it, no questions about it.

So according to those hydraulic gurus, it is impossible to test a cylinder and all cylinders should just be rebuilt if there are ever any questions, because, well there is no way to test them.

Give me a moment Brian, I'm old and not very bright.........

If the cylinder extends an inch, it has removed the mass of 1 inch of ram space from the equation. So that space MUST be replaced with something. It can't get additional fluid because the circuit is closed by the hydraulic hose couplers. So,,,,, for it to move a fraction of an inch it MUST get space from somewhere, i.e., either breach the "ram to environment seal" and suck air, or breach the "hose coupler seals" and get air.

If neither happens that does nothing to prove the cylinder is solid, because it cannot move, regardless of cylinder pressure seal condition.

How to test a cylinder, I believe, requires flow or pressure gauges be installed, which is wayyyyyy beyond my intelligence.

 

[MtnViewRanch]

Give me a moment Brian, I'm old and not very bright.........

If the cylinder extends an inch, it has removed the mass of 1 inch of ram space from the equation. So that space MUST be replaced with something. It can't get additional fluid because the circuit is closed by the hydraulic hose couplers. So,,,,, for it to move a fraction of an inch it MUST get space from somewhere, i.e., either breach the "ram to environment seal" and suck air, or breach the "hose coupler seals" and get air.

If neither happens that does nothing to prove the cylinder is solid, because it cannot move, regardless of cylinder pressure seal condition.

How to test a cylinder, I believe, requires flow or pressure gauges be installed, which is wayyyyyy beyond my intelligence.

Ok, watch the video. No trick photography was used in the making of this video, and no I am not the strongest human that has ever lived. ath: