hydraulics on Grapple slow

   / hydraulics on Grapple slow #1  
J

JYD

Bronze Member
Joined
Dec 25, 2006
Messages
60
Hi All!!
Question
I have a JD 4320 with root grapple. Sometimes the grapple arm is very slow to close and other times it operaters fine.

Any idea why sometimes it is so slow to close???

Your help is appreciated

JYD
 
   / hydraulics on Grapple slow #2  
Are you operating the grapple through a diverter or are you using the 3rd SCV?
Does the engine bog down when its operating slow like it's straining to move the cylinder?
 
   / hydraulics on Grapple slow
  • Thread Starter
#3  
Yes I have a 3rd SCV installed in the front. Engine does not bog at all. I have no problem with the FEL or PTO
 
   / hydraulics on Grapple slow #4  
Is your fluid level full ?
Jim
:)
 
   / hydraulics on Grapple slow
  • Thread Starter
#5  
I will check the fluid level. The Tractor is at my cabin in northern Wisconsin, I will be back up there in 2 weeks. I am hoping it is lower on fluid as that would be a easy fix.

I will let you know

If fluid ok, then what?
 
   / hydraulics on Grapple slow #6  
JYD said:
Yes I have a 3rd SCV installed in the front. Engine does not bog at all. I have no problem with the FEL or PTO
Click to expand...

If the engine was bogging, I would have suspected a malfunctioning QD, but since it's not, I will guess the seals in the cylinder are bad and leaking internally.
 
   / hydraulics on Grapple slow #7  
JYD said:
I will check the fluid level. The Tractor is at my cabin in northern Wisconsin, I will be back up there in 2 weeks. I am hoping it is lower on fluid as that would be a easy fix.

I will let you know

If fluid ok, then what?
Click to expand...

Make sure that you bleed your system of all air with full extensions of all hydraulics both ways.
all the way extended and all the way retracted of ALL hydraulic functions, That's what Andy at Wayne County Hydraulics told me Shh
Jim
:)
 
   / hydraulics on Grapple slow #8  
Sounds like you have summer seals inside your cylinders. Summer good, summer not. Sometimes the piston seals do this depending on what style they are. They roll over and don't seal, then they will roll back and be okay for a while. When it does this, try rocking the lever back and forth but not too fast. See what happens.
 
   / hydraulics on Grapple slow #9  
When the grapple is slow, are you also operating the loader or any other hydraulic implement? I'm not familiar with how the Deere is set up, but if you are operating something else at the same time you will be sharing the available hydraulic flow between the two functions rather than dedicating it to one. This will slow down both functions. Also, if you have something in series after the grapple then it can be creating backpressure which will slow down the grapple.

I'd suggest trying to zero in on exactly what you are doing when the grapple is slow, and how it's different from when it's fast. I've found it's real easy to be operating two things without really being conscious of it.
 
   / hydraulics on Grapple slow #10  
JYD said:
Hi All!!
Question
I have a JD 4320 with root grapple. Sometimes the grapple arm is very slow to close and other times it operaters fine.

Any idea why sometimes it is so slow to close???

Your help is appreciated

JYD
Click to expand...

Did you build the grapple hydraulics, or was it done by your dealer? Is it possible the dealer installed a small orifice or metering valve in line and it is being clogged? As kennyd noted, you should hear the tractor load up some when you try to operate the grapple.

I don't think it's an internal seal, because this normally causes the grapple to droop even when you release the SCV control valve. The grapple would droop or have no holding power.

Is it only slow in one direction? Closing? Can you swap the lines to see if the problem direction changes? That would tell you lots.
 
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