Bought Ford 777F FEL and it is leaking down rapidly

[Browning12]

the bottom of cylinder sits inside a square box which sits inside another square box housing. no access to the bottom of the cylinder, ill look for some pics, and it appears once you pull the pin from the top of the box the bottom would pull out as you back up the tractor. Kind of odd only 2pins would hold on the entire loader, but i guess weight of the loader would be pushing down all the time? The fact I can see oil on the silver part of the cylnder makes me think a seal is bad, also when I had bucket off the front cylinder would fall open, would gravity do this? I could understand if tractor wasnt running but it was running, so essentially both systems (large pickup) and small front bucket cylinders are leaking down while tractor is running. Loader sit couple years in field unused so im wondering if this caused them to go bad , have to get that gauge and see, do you screw the gauge into the hose that is going to each cylinder or just get a a connector and plug it in the quick connects on the tractor?
Thanks!

 

[Browning12]

 

[Browning12]

here is a cheaper CV, it says 20GPM though
2 Spool Hydraulic Directional Control Valve for Two Double Acting Apps | eBay

 

[Dave M7040]

When you have the lack of lift strength and leak down I have learned to suspect the o ring that seals the piston to the push rod. Usually the piston is connected to the push rod by a large nut. The push rod will have a groove for a small o ring to seal to the inside bore of the piston. These o rings are about 1" in diameter. These o rings fail and then you have an internal leak which does not show up outside the cylinder. Don't buy a seal kit as they are often expensive and unless you have an external leak are often not needed. The small o ring can be found at a hydraulics shop for pennies.
o ring #18 in the photo is the one I am referring to. This is not the cylinder you have but is similar!
Dave M7040

 

[Browning12]

I hope this is it, that is great advice, if it is only the O-ring I'll be in good shape, I really appreciate the direction, I will keep you posted

 

[Browning12]

got the gauge, it appears on the lift hose, goes to 2250 , then drops to <500 immediately when I let off the lever, the drop side goes to 2250 then drops to 1500, holds for about a minute, any ideas if this is my issue (factory Control valve leaking down?) If this is the case when I get my new Control valve installed on the loader will I tie up the levers on the factory CV to always be applying LIFT?
Thanks!

 

[Dave M7040]

Before replacing the control valve consider removing the hydraulic lines from the control valve to conduct a test.

Jack the bucket up a few inches then remove the hydraulic lines with a jack supporting the bucket. Cap the line on the lift side of the cylinder and leave the down line open. Add weight to the bucket and watch your pressure gauge and also for oil coming out down line as you lower the jack. Removing the jack will pressurize the cylinders. If you are loosing pressure with the bucket loaded and the control valve no longer in the circuit you have established the problem is an internal leak in the cylinder(s).
Dave M7040

 

[J_J]

If you install the new valve and the cyl is good, you should be able to activate the relief on the loader valve, and read the pressure.

The cyl, if good will hold the load up for a long time.

If the cyl is leaking, the relief probably will not operate.

If the cyl leaks down after installing the loader valve, then the other possible causes are o-ring on the rod nut on the cyl, or piston seals worn.

 

[J_J]

got the gauge, it appears on the lift hose, goes to 2250 , then drops to <500 immediately when I let off the lever, the drop side goes to 2250 then drops to 1500, holds for about a minute, any ideas if this is my issue (factory Control valve leaking down?) If this is the case when I get my new Control valve installed on the loader will I tie up the levers on the factory CV to always be applying LIFT?
Thanks!

On a loader valve that is working correctly, you will not need to tie off anything, as the spools in neutral are supposed to hold the load for a while.

Most all loaders will drop over time. Some stay up days, weeks months, and others, you can watch them descend,