Kubota L3300 hydraulic pressure surging

[hankws]

Hi, I have a Kubota L3300 and the hydraulic system pressure seams to be surging. The 3-point oscillates with a heavy load and the pressure line to my front loader valve bounces at the same frequency.

 

[J_J]

You may be working with a load that causes the relief valve to release.

As the tractor bounces, more load is induced and the relief keeps going off.

Are you shifting the 3pt valve back to neutral, or keeping the lever is the raise position?

Once you put the 3pt lever to neutral, the FEL would be independent, and unless you were using the loader, the hyd fluid would just pass through each valve to tank.

 

[LD1]

First, Define "heavy load"

Could be what JJ suggested. It also could be sucking air from somewhere. Air wont raise the implement. But if it gets a little fluid pumping, it will raise a little until another air-pocket hits.

 

[hankws]

Thanks for respondinding! First the load on my 3pt is a 6 foot finish mower. That was the only implement that oscillate (bounce). Second the hydraulic lines feeding the loader valve flex even with the 3pt lowered but more noticable when it is raised. I have replaced 3 hyd. hoses on the loader valve because of leaks. This is a '96 tractor and they were original hoses, but I think the pressure surges caused the leaks. The hyd. fluid looks clear with no foam in the site glass. Also I cannot locate a relief valve in the parts manual.

 

[J_J]

There should be a relief valve on the FEL valve close to the IN port.

The 3pt also has it's own relief valve somewhere under the seat.

Show us some pictures of your loader valve.