valve slippage leaking seals

[cosworth34677]

ok i got two more hydrulic problems

1. i got a set of valves that work great they move great . and what ever i hook to them move great.....but......
they won't hold, the excavator arm will slowly stat to fall, and i have replaced the little orings in them helped them in moving better bet they still won't hold, even if i take off the servo and try to find the center it still will slowly fall.
is there a fix? this is the version two magom hrc valves.

2. i got a set of valves the will hold and work..... but kind of slow, they always been kind of slow moving even new. but they have this funky leak thing hear they leak around the orings where the shaft on the valves come out of the valve. the shaft that hook took the servo adapter , is there a fix for that? i have replaced the o rings, just not the little plastic wash between the oring and the valve. these are the version 3 valves from magom

both are two- four years old .

any help would great thats

[Flycop2000]

Hi,
did you ever get this problem fixed?
I have a similar problem, the main boom on my excavator drops very, very slowly over time. I replaced the O ring wiper seals, used silicone grease on the seals as well but still have this problem.

[avel]

Leimbach has an unlockable check valve that might help.

https://www.der-getriebedoktor.de/le...ckschlagventil

[frizzen]

It could be the valves not fully sealing, or the hydro ram is leaking across piston seal from pressure to return sides

Do all of your hydro channels do that?

How slow is "drops very very slowly over time"? Are we talking like a quarter hour, couple days?

[Flycop2000]

Hi,

It's only the main boom that drops, It goes down from fully up postion to half way over about an hour then very very slowly completly drops over about 12 hrs.
I have noticed that after the boom drops to half way point I can lift it by hand to the full up postion.

[frizzen]

I don't run model hydros, but my quick & dirty troubleshooting suggests swapping hydro lines at the block with another valve, then swap their servo plugs at the recciever.

Problem follows same cylinder on new valve, it's probably the cylinder seal

Problem stays on same valve with new cylinder, probably valve seals.

Problem jumps to another unrelated cylinder or valve, it's got gremlins or ghosts.

[skeeter]

slow leak down, in my experience (I've not experienced the expensive German components) is normal. Even the 1:1 machines have slow leak down.

My wheeled loader, the minute I shut er off, & walk away, the bucket slowly starts to bleed off. Same goes for the RC4WD 4200 XL that I use to own.

As to the oil leak, there shouldn't be any leakage where the servo connects to the valve body.

[Flycop2000]

Hi,
thanks for all your sugestions, I've checked for leaks and there is none that I can find.
I should have mentioned earlier that my excavator is a Metalhobi hydromek 490. I've not had it very long and can't remember if it always did this from new as I had a spell where I did not use it much due to other commitments.
If slow leak down is normal, I can relax and stop looking to fix a non existant problem.

[Surge]

I am experiencing this slow leak down with a single-acting single hydraulic cylinder track dumper from ScaleArt. If there’s even a small load in the dumper bed, it will slowly drop down when raised. BUT - the pump is not always running. It’s set to only run when raising or lowering the bed. I assume that’s why the dump bed is dropping slowly? If the pump were always running, it should not drop, correct?

[skeeter]

Originally Posted by Surge

I am experiencing this slow leak down with a single-acting single hydraulic cylinder track dumper from ScaleArt. If there’s even a small load in the dumper bed, it will slowly drop down when raised. BUT - the pump is not always running. It’s set to only run when raising or lowering the bed. I assume that’s why the dump bed is dropping slowly? If the pump were always running, it should not drop, correct?

Even my hydraulic wheeled loader experiences bleed down, a bit. It's SLOW, but it is normal. Heck, even the real life machines experience it to some degree.

[Surge]

So there are no leaks - I cleaned all the oil residue and nothing new has seeped out. I think it was from shipping - the model was undoubtedly tilted, and some oil leaked out.