Getting tired of hydraulics- Another help needed thread

[futuresweets10]

I had the valve assembly for the FEL of my backhoe "rebuilt" at a local shop. I told them to go through everything on it and replace every part that was replaceable and inspect everything else. Got the valve assembly back and installed it and the FEL bucket still wont work right. I assumed it had to be the cylinder, but after testing there is nothing wrong with the cylinder.

If I pick the FEL arm up the bucket falls all the way down to the lowest point. I had assumed it was by passing, but I played with it for about an hour today. If i set the bucket down flat on the ground and try to tilt the bucket down it will tilt down and lift the front of the machine like it is suppose to do. Once I do that I can tilt the bucket back up and it will tilt until its flat. It only tilts up until its flat and no further. Its obvious that the retract function (tilt bucket down) works, but the extend function of the cylinder does not work.

I obviously dont have a problem with a cylinder or valve by passing because that would be all the time (even when the bucket was on the ground). Right? The shaft end of the cylinder is getting fluid when I push the stick to the left and its letting the fluid back out when I push to the right. However, when I push to the right it isnt sending pressure to the butt end of the cylinder. Doesnt this have to be a valve problem? Any ideas what it could be so I can have knowledge when i go back to the shop and complain that they didnt do something right?
HELP!!!

 

[AKKAMAAN]

are there any inline valves between control valve and cylinder?
are there any work port valves on/inside the control valve?

 

[futuresweets10]

are there any inline valves between control valve and cylinder?
are there any work port valves on the control valve?

Straight line between control valve and cylinder
Not too sure what is meant by work port valves... Tried to google it, but couldnt find anything.

I would assume it does have them being that it has everything else known to man on it....

On another note... When i push the stick to try to get the bucket to curl up I hear a hissing sound comming from the valve assembly.... Almost sounds like what a fluid spray (leak) would sound like, but no leak

 

[AKKAMAAN]

Straight line between control valve and cylinder
Not too sure what is meant by work port valves... Tried to google it, but couldnt find anything.

I would assume it does have them being that it has everything else known to man on it....

Work port valves are built into to the control valve housing, either on the bottom of the valve (under the spools) or just by the work port (where hoses are connected). I assume there is a work port relief valve for the bucket....or eventually an inline valve.....follow hoses from cylinder back to control valve to check if there is any thing plumbed in between.....

You had that previous "crashed" pump, so expect some metal debris cruising around in the system...probably something is holding a work port relief valve a little open so flow by passes

 

[futuresweets10]

Work port valves are built into to the control valve housing, either on the bottom of the valve (under the spools) or just by the work port (where hoses are connected). I assume there is a work port relief valve for the bucket....or eventually an inline valve.....follow hoses from cylinder back to control valve to check if there is any thing plumbed in between.....

You had that previous "crashed" pump, so expect some metal debris cruising around in the system...probably something is holding a work port relief valve a little open so flow by passes

I already checked and there are no other valves in line between the cylinder and valve assembly.

Can you tell by these pics if there is work port valve on the assembly? If so, can you point out what it is?

 

[David Devuono]

Interesting problem. Let us know the kind of tractor, if it came on suddenly or slowly started acting up. Age, hours on tractor. Did they say they found anything with the control valve? How long have you owned the tractor? Do you have to select between Loader and 3pth? You described hearing a hissing sound, was the bucket or arms dropping when you heard the hissing. I am not sure how much room you have to play with hoses, but if the FEL arms go up and down normal, could you not switch the working ports and see if the curl now works and the lift starts acting up?

If you where to put the tip of the bucket on a stump, and curl the bucket back (it was only curling to level position) and at the same time push down with the lift arms will the bucket curl back. If not, it may be seizing. With the tractor shut off and someone curling the bucket back, can you manually tilt the bucket back?

I like to isolate things, while its messy, you could even use compressed air to operate the cylinder with hoses disconnected, ensure you can force the bucket cylinders through their full range of motion. Good Luck

 

[David Devuono]

My valve only has an inlet, outlet and the four work ports. Hopefully the experts can help you on that contraption

 

[futuresweets10]

Its a cat 416b back hoe

 

[AKKAMAAN]

I already checked and there are no other valves in line between the cylinder and valve assembly.

Can you tell by these pics if there is work port valve on the assembly? If so, can you point out what it is?

 

[futuresweets10]

I already checked and there are no other valves in line between the cylinder and valve assembly.

Can you tell by these pics if there is work port valve on the assembly? If so, can you point out what it is?

Well, Now that we have established that I do have work port valves, whats the next step? Could these have a problem, or could they need adjusted?

If I have access to them, can I just unscrew the work port valve from the valve body and remove it to inspect it, or are there small parts like springs and other things that will fall out if I unscrew it?