hydraulics problem

questadg · Feb 1, 2011

I have a 3820i and changed hyd oil/filter @ 300 hours per recs. Now, I notice that the hydraulics kind of "skip" when the 3. and the bucket are lifted. When the 3. or bucket are lifted, they jerk every 30 seconds or so. Is there air in the system? If so, how do I bleed it? Could ther be another problem? This did not happen when I did the initial change. Everything still works but I am not comfortable with the "jerking" or "skipping."

Craig Clayton · Feb 1, 2011

If your hydraulic filter is on the suction side of the pump you might be sucking in a tiny bit of air, and that will never bleed out. If you have trapped air in your cylinders the standard method is to do a full stroke but there is no need to pop the relief. I would suggest you recheck the filter first.
Craig Clayton

J_J · Feb 1, 2011

questadg said:
I have a 3820i and changed hyd oil/filter @ 300 hours per recs. Now, I notice that the hydraulics kind of "skip" when the 3. and the bucket are lifted. When the 3. or bucket are lifted, they jerk every 30 seconds or so. Is there air in the system? If so, how do I bleed it? Could ther be another problem? This did not happen when I did the initial change. Everything still works but I am not comfortable with the "jerking" or "skipping."

Since the 3pt and FEL are in series, and the FEL gets the fluid first. Now you are trying to use the FEL and the 3 pt at the same time, the FEL may take all or most of the fluid , and the 3pt is left starving for fluid. If the FEL is using half, the other half of the total flow is available to the 3pt

DavesTractor · Feb 1, 2011

questadg said:
I have a 3820i and changed hyd oil/filter @ 300 hours per recs. Now, I notice that the hydraulics kind of "skip" when the 3. and the bucket are lifted. When the 3. or bucket are lifted, they jerk every 30 seconds or so. Is there air in the system? If so, how do I bleed it? Could ther be another problem? This did not happen when I did the initial change. Everything still works but I am not comfortable with the "jerking" or "skipping."

Did you use a Branson filter, or an aftermarket filter? Some of the aftermarket filters are a little too fine and struggle to get enough oil through them, especially cold oil. If just the three-point jumps every 30 seconds or so, I'd suspect the rings/seals on the rockshaft piston. If the loader does it also, then probably air.

questadg · Feb 1, 2011

I used a Branson filter from my dealer. I did the same thing as when I changed the fluid/filter the first 100 hours. The only other info I didn't mention is that I have a backhoe attachment and I'm wondering if any air got trapped when I unhooked it? The problem does not affect the funtion of the FEL or the 3. but I am worried that it may be a signal of a bigger problem to come. I have not noticed any leaking other than the little bit that happens when I remove or re-hook the backhoe. Thanks for your replies.

DavesTractor · Feb 1, 2011

questadg said:
I used a Branson filter from my dealer. I did the same thing as when I changed the fluid/filter the first 100 hours. The only other info I didn't mention is that I have a backhoe attachment and I'm wondering if any air got trapped when I unhooked it? The problem does not affect the funtion of the FEL or the 3. but I am worried that it may be a signal of a bigger problem to come. I have not noticed any leaking other than the little bit that happens when I remove or re-hook the backhoe. Thanks for your replies.

Probably just a little air, no need to bleed anything. It will work its way out of the system.

YanmarFever · Feb 2, 2011

I always pour some hyd oil inside the new filter before I install it.

It helps push out any trapped air inside that may cause the problem you're having, it worked for me when I serviced Bransons .

oldgreymare · Aug 20, 2011

RE: hydraulics problem
I have a 2010 4720i with a bucket problem. It doesn't dump all the way...it floats until you wait for it to catch up.
The backhoe also has a problem. It's very jerky and unpredictable. It should be smooth and controllable. Have you run across these problems?

Oldgreymare

J_J · Aug 20, 2011

Might be air in the system, but if you have extended and retracted the cyl several times, the air should have been expelled.

Is the hyd fluid at the correct level?

If there is something that affects two different valves, that indicates that the pump may be at fault, maybe sucking air and passing it to all the cyl.

You might install a hyd gage, and see if you have the pressure where it is supposed to be.

Does the PRV activate, or relieves the pressure?

Did you make a change on something recently, or has the machine been doing this for a while?

DavesTractor · Aug 20, 2011

oldgreymare said:
RE: hydraulics problem
I have a 2010 4720i with a bucket problem. It doesn't dump all the way...it floats until you wait for it to catch up.
The backhoe also has a problem. It's very jerky and unpredictable. It should be smooth and controllable. Have you run across these problems?

Oldgreymare

JJ has great suggestions as always.

You could disconnect the backhoe hydraulics to see if the loader still acts up, and conversely disconnect the front loader and see if the backhoe acts up. That will see if isolating one or the other makes any difference.

If that does not make a difference, then you may have air in the system, or a clogged filter. If you have a set of remotes on the tractor but nothing hooked up to them, make sure the lever is not in detent trying to push pressure out of a working port and therefor bypassing the pressure relief.