Slow Lift Arm Leak Down 8N

[Orion231]

So, a while back I did a major rebuild on the hydraulics but due to a number of factors, I only just started to use the tractor again. I rebuilt the hydraulic pump and replaced the PTO shaft. I completely rebuilt the upper controls including a new lift cylinder and lift piston. The piston I installed was the one with the oring and leather backer. What a pain.

Anyway, I am now wanting to get busy with my implements but having trouble with leak down of the lift arms. If I turn the tractor off and stand on the lift arms, they settle down in about a minute. I just pulled the inspection cover with the dipstick. Looking in the inspection port with the tractor running, moving the lift control up and down I don't see any problems with fluid leaking from above or bubbles in the pump area. I did straighten the pump control arm and adjusted it as best I could to the instructions. The new scotch yokes have a little bit of a knock sound to them but hoping that will go away as they wear in or seat.

Any thoughts on why the arms leak down so quickly? If the lift cylinder is leaking past the piston seals, is there any way to know that before tearing the whole thing apart again?

This post was edited by Orion231 on 07/24/2022 at 08:46 pm.

 

[Den N Ms]

Orion231 , Put a heavy implement like a rotary cutter/disk on the 3 point ,remove the inspection port.Start it up and raise the lift and with a bright flash lite look for oil leaking from backside of the cylinder ,pipe at the side of the case ,gasket at top cover.Shut engine off and continue to look for leaks,control valve and pressure relief valve.Re start if needed to raise again.

 

[Orion231]

So, I loaded up my heavy 6 foot brush hog. It holds in the up position as long as the tractor is running. It is hard to see inside the inspection port since the tire is on and I have a jungle gym front loader on it. I used my cellphone to get a video of the tube from the bottom to the top cover as I cycled up and down. I also used an inspection camera with a flexible probe. I can't find any leaks at the top of the tube and there are no bubbles anywhere.

I just did a timed test and it settled about halfway in a minute but then its taking 10 or more minutes to settle the rest of the way. I guess I will put the cover back on and use it the way it is. Maybe the piston seal finally seated itself correctly. The scotch yokes make a little more rattling noise with the lift full up.

This post was edited by Orion231 on 07/25/2022 at 11:48 am.

 

[JMOR]

(quoted from post at 05:43:22 07/25/22) Orion231 , Put a heavy implement like a rotary cutter/disk on the 3 point ,remove the inspection port.Start it up and raise the lift and with a bright flash lite look for oil leaking from backside of the cylinder ,pipe at the side of the case ,gasket at top cover.Shut engine off and continue to look for leaks,control valve and pressure relief valve.Re start if needed to raise again.

As Den in MS said & here is a drawing of potential leak points. Need to lower oil level to see some of them.