Hydraulic Cylinder Leak Down on Box Blade???

[Piston]

My hydraulic cylinder on my Gannon/Frontier box blade is leaking down fast. I thought it was just bad seals, so I ordered a seal kit from Messicks.

I replaced the seals on the cylinder last night (ya I know, pretty exciting New Year's Eve for me) and hooked it up to my tractor. I tried it out, and again, instant leak down???

What happens is, sometimes when I fully raise the scarifiers, they will remain in the up position, but then if I bump the valve stick it starts leaking down fast enough to watch the whole process. It's not like this every time, as sometimes it will leak down without bumping the valve stick. I thought maybe it was my valve (although nothing else leaks down) so I raised the scarifier bar all the way up, disconnected the hydraulic hoses, and again, leak down to the floor??? This ruled out the valve, and there was no hydraulic fluid leaking out, so something in the cylinder is leaking by.

I did take a couple video's of this. Nothing great, but shows what I'm trying to explain...

Also, when I was replacing the seals, I noticed these small ports in the silver bottom 'cap' that attaches to the rod. (I don't know what they are called, and this is my first time opening up a cylinder, so I don't actually know what I'm doing anyways) The smallest port you see in the photos is the one with the metal shaving stuck in it, it seems like something was stripped out in there.


Are these ports supposed to be adjusted? Do they have seals I should be replacing? Is it possible these are letting oil flow through which is causing my leak down issue?

Inside one of these ports, I noticed a metal shaving type piece of metal, inside one of the ports. I did take a photo but hard to see. Could this be my problem?


Is it possible there is just air in the cylinder and it needs to be bled more? At this point, the box blade is really unusable as the scarifiers leak down way too fast.

 

[Piston]

I could only add one video per post, this is the one with the hoses disconnected from the tractor...

 

[nybirdman]

Looks like you have a problem with the valve itself.Shavings in the valve/spool.

 

[GMIslander]

Looks like you have a problem with the valve itself.Shavings in the valve/spool.

Probably not with the hoses disconnected. What does the bore of the cylinder look like?

 

[Piston]

It looked pretty good, there weren't any gouges or dents that I could see.

I believe I installed all the seals correctly, it doesn't seem like rocket science to replace them

I don't think there was anything wrong with the seals to begin with though, I imagine my problem has to be with those "ports" that are in the silver pieces. What are those there for?

 

[jenkinsph]

Piston,
Assuming you cleaned everything before reassembly including hoses of any filings I would plug it back in and cycle it several times. When reaching the upper and lower limits I would hold it in relief for a second to aid in removing any air from the system.

Mine will stay up for a few hours at a time, I may have to touch the control two or three times in a days use with the box blade. After the tooth bar drops slightly.

 

[npalen]

Did you check the inside (bore) of the cylinder? The chip down inside the small hole is very suspicious and there may have been others that scored the inside of the cylinder. I hope that chips didn't pass into the tractors hydraulic system.

 

[KWentling]

So the cylinder is extending when it settles. Correct? You have replaced the seals and the tube is good, so that leaves us with the port on the piston. I've not seen that before, but I would guess that would be for an over pressure relief of some sort. So, it's either missing, stuck open, or missing parts. Maybe that "metal shaving" is a clue to that.

 

[jenkinsph]

So the cylinder is extending when it settles. Correct? You have replaced the seals and the tube is good, so that leaves us with the port on the piston. I've not seen that before, but I would guess that would be for an over pressure relief of some sort. So, it's either missing, stuck open, or missing parts. Maybe that "metal shaving" is a clue to that.

No, the cylinder is retracting when it settles down. If you look at my picture and expand it you can see the rod is facing down and is connected to a clevis which is welded to a horizontal pin. The lever to raise the gang scarifiers and this clevis for the cylinder are both welded to this pin, It has to be air in the cylinder or lines since it would do this with the couplers unplugged and no leaks.

 

[jenkinsph]

Here are some better pictures of the linkage.