3-pt Not Lifting Completely

[budlite]

I recently purchased a grapple for my JD 5303. Since I added the grapple, my 3-pt hitch will not completely lift the rotary cutter off the ground. I have added hydraulic oil and checked the level several times and the problem persists even with the grapple removed and hydraulic hoses disconnected from the rear remotes. I thought maybe the system needed to be bled, but can find no mention of bleeding the hydraulic system in the service manual. I am about to go and do a thorough check for leaks, any help would be appreciated.

Thanks

 

[J_J]

JD 5303

Hydraulics:
Type: open center
Capacity: 10 gal [37.9 L]
Pressure: 2800 psi [193.1 bar]
Valves: 1 or 2
Pump flow: 9.5 gpm [36.0 lpm]
Total flow: 16.3 gpm [61.7 lpm]
Steering flow: 6.8 gpm [25.7 lpm]

Install a hyd gage and see if the relief pressure is correct.

The hyd system will self bleed.

Grapple should not affect anything as they use work ports .

Could you pick up the attachment before?

Check the pressure and determine if the pump and cyl are good.

If the 3pt cyl seals are leaking, then you might not be able to raise the load.

 

[Tx Jim]

Was this added grapple control valve JD or aftermarket? I agree with J_J on the need to check system pressure. Where is draft control lever set?? Which hole on center link bracket is center link attached on your tractor?

 

[budlite]

I used the existing JD rear remotes for the grapple third function. I do not have a pressure gauge, need to get one. I have tried different draft control settings with no appreciable difference. The center link is attached in the center hole. I thought I posted this reply a few hours ago, don't know what happened.

 

[Tx Jim]

Since you're utilizing the tractor remotes to operate the grapple then 3 pt not raising high enough should be just coincidental. As to the bleeding of system all you can do is cycle the newly added cylinders to purge the air. How long since you changed hyd filter?

 

[budlite]

Changed fluid and filter at 50 hrs, about 250 hrs now. I have tried extending cylinders and been adding fluid. Don't think its a pump/pressure problem as I used the grapple to lift HEAVY tree trunk up pretty high to get over a fence to dump without a problem. Need to take another look at the center link to ensure I have not done something different (i.e., dumb).

 

[J_J]

Good pressure on the FEL has nothing to do with the pressure of the 3pt, as it has it's own relief valve, and if the cyl is leaking, you will not see the pressure.

However, if you install a pressure gage in a tee the FEL IN port, it will tell you the pressure required for each circuit.

For instance, like you said, you lifted a heave tree, and the cyl developed the pressure to do the job.

The 3pt hyd circuit could be faulty, and not develop the pressure required to do the job.