Hydro leak down 3510

[taxidermist1]

I have a 2yr old 3510 with 90 hr It just started to have leak down when the bucket is left raised off the ground for a few hours?? I have no external leaks that I can see?



Thanks,
Rob

 

[FrankenmuthTom]

Why do you want to park it with the bucket in the air?

 

[JerryG]

That is normal thing. Fluid bypasses the piston in the cylinders and it also bypasses in the spool valve.

 

[taxidermist1]

Well I was using the fel to move a trailer around and it was supporting the trailer while it was hooked up. You say that is normal for it to leak down???????? Why did it just start at 90 hr??? None of my other tractors do this.

Rob

 

[Stimw]

Make sure handle on joy stick is going back to neutral and working free. Sometimes they will stick and let them leak down. Might need to lub to free up.
Hydralic lift cylinders have a piston with seals on both sides. If the seal starts leaking it will let fluid by pass. Sometimes you can work the cylinder from one extreme to the other and reset the seal, or clean a piece of trash from under the seal lip.

 

[DigDug]

I'm something of a newbie here...is it really normal for the FEL to leak down? I would expect that the system should be closed and maintain pressure when working properly?

Wouldn't there have to be a leaky seal somewhere to release the pressure?

 

[Zork]

I would hope that it was a valve controller problem and not seals in the hydraulic cyl's. The valve spool is easy enough to replace and while not normal in my opinion (for quality, newer non abused equipment) it should not effect the overall "running" performance. However, in my opinion, I think, if the seals in the cyl. are leaking it will eventually effect and seriously limit your overall lifting capacity. I've seen cyl's. creep before, but it was always on equipment with lots of time on it, and it was "normal" for that amount of wear or time. I too have this problem on my bucket and my boom on my backhoe. I havent noticed any performance issues. I havent worried too much about it since I am not leaking any fluid to the outside of the cyl. shaft, which would probably happen if my cyl seal was bypassing/ leaking during operation. /forums/images/graemlins/grin.gif

 

[Stimw]

Internal bypassing and external leaking are two different issues. When bypassing fluid leaks from the side under pressure to the non pressure side and will return to the reservore in a double acting cylinder if the shaft seal is good.
Here is a crude example of the piston in a cylinder, ----)(- . It has to hold pressure in both directions, if one side fails fluid will travel to non pressure side. tim

 

[Zork]

Oh, Thank you. So if the cyl shaft seal only leaked at full extension (at load) would this not be the case?