Backblade upgrade!

[CADplans]

Not quite. The crossover on a DA cylinder will only allow it to rotate one way on its own without operator input

,,,,,,,,,,, depending on lots of factors, like air in the system, and whether this high pressure can get oil past the piston seal of a $99 cylinder .

Even at that, OCD will not allow one to have any rotation of that blade, one direction, or not,,

 

[LD1]

,,,,,,,,,,, depending on lots of factors, like air in the system, and whether this high pressure can get oil past the piston seal of a $99 cylinder .

Even at that, OCD will not allow one to have any rotation of that blade, one direction, or not,,

Sure, if there is air in the system can cause a little blade movement. But a proper functioning system wont have air in it, only oil. And it dont matter if its a $99 cylinder or a $999 cylinder.....oil cannot move past the piston if the rod is trying to retract. Not even a little bit. A crossover will only protect when trying to extend the cylinder....but that creates another problem....you are sucking air in the gland seal. Air and god only knows what other contaminates and dirt/dust/water.

A crossover is designed for something with equal displacement, like a double rod cylinder, or a pair of equal sized single acting cylinders...or like trying to run a hydraulic motor with high inertial load off a tandem center valve and not a motor spool.

 

[npalen]

Sure, if there is air in the system can cause a little blade movement. But a proper functioning system wont have air in it, only oil. And it dont matter if its a $99 cylinder or a $999 cylinder.....oil cannot move past the piston if the rod is trying to retract. Not even a little bit. A crossover will only protect when trying to extend the cylinder....but that creates another problem....you are sucking air in the gland seal. Air and god only knows what other contaminates and dirt/dust/water.

A crossover is designed for something with equal displacement, like a double rod cylinder, or a pair of equal sized single acting cylinders...or like trying to run a hydraulic motor with high inertial load off a tandem center valve and not a motor spool.

The "oil cannot move past the piston" is probably one of the most understood principles in hydraulics. To help visualize, think of a cylinder with a rod but no piston. Try to push the rod into the cylinder full of oil with both ports blocked. Might say, "ain't gonna happen".
The rod, in the above scenario, is basically a piston with bad seals.

 

[LD1]

The "oil cannot move past the piston" is probably one of the most understood principles in hydraulics. To help visualize, think of a cylinder with a rod but no piston. Try to push the rod into the cylinder full of oil with both ports blocked. Might say, "ain't gonna happen".
The rod, in the above scenario, is basically a piston with bad seals.

Yes, it is very well understood by many.

However, here in TBN it is VERY frequently misunderstood. Especially when it comes to a loader drifting down.

 

[4570Man]

Yes, it is very well understood by many.

However, here in TBN it is VERY frequently misunderstood. Especially when it comes to a loader drifting down.

A leaky cylinder seal can’t be the sole cause of loader leak down but it will make the problem worse. A leaking piston seal will cause increased pressure in the cylinder due to less surface area and it would have to loose less fluid to leak down.

 

[npalen]

Yes, it is very well understood by many.

However, here in TBN it is VERY frequently misunderstood. Especially when it comes to a loader drifting down.

Yes, I meant to say "misunderstood". My bad.

 

[npalen]

A leaky cylinder seal can’t be the sole cause of loader leak down but it will make the problem worse. A leaking piston seal will cause increased pressure in the cylinder due to less surface area and it would have to loose less fluid to leak down.

Can you elaborate on this? Where would the lost fluid go? I can see what you're saying if you mean it is leaking past the valve spool.

 

[4570Man]

Can you elaborate on this? Where would the lost fluid go? I can see what you're saying if you mean it is leaking past the valve spool.

It could be leaking on the ground somewhere either from the gland seal or a hose. But assuming that’s not happening it goes back through the valve.

 

[LD1]

Yes, I meant to say "misunderstood". My bad.

Yes, on TBN its is pretty misunderstood. But outside of TBN....just about everyone I have ever dealt with regarding cylinders and hydraulics in general that work in the field understand. I do not understand why it is so misunderstood on TBN, and why bad info and advice continues to be spread.

 

[LD1]

A leaky cylinder seal can’t be the sole cause of loader leak down but it will make the problem worse. A leaking piston seal will cause increased pressure in the cylinder due to less surface area and it would have to loose less fluid to leak down.

Yes, a worn cylinder will exaggerate the root cause of the issue, rather than be an external leak or an internal valve leak. But its not uncommon to have other symptoms along with it. Such as weak lift.

At the end of the day, it is really simple to test the components. But too many people just throw parts at it and hope for the best. Id rather take time to troubleshoot and fix what is needed, rather than replace parts that might be perfectly fine