Very slow loader bucket curl on a 3520 with 300X

[Spindifferent]

Hi Folks,

I need to consult with the collective wisdom of the TBN community on an issue I'm having with my 2005 JD 3520 with 527 hours and a 300X loader on it.

The issue is that the loader bucket is curling very (extremely) slow now. It is very slow in both curling up and curling down, and I must apply lots of pressure on the loader control lever to get the bucket to move at all; almost to the point of bending the actual lever.

The 3 point and the loader lift cylinders work just fine.

Here's what I've done to troubleshoot the issue:

- Confirmed the correct amount of hydraulic fluid
- Disconnected and reconnected the hydraulic line couplers
- Inspected the hydraulic hoses and connectors for leaks
- Confirmed that the SCV lock lever is in the unlocked position
- Tested the bucket curl at various engine RPMs including PTO speed
- Greased all loader connections

The 3520 manual suggests that the suction side filter should be replaced or to check for water if the hydraulic performance is poor. Since the 3 point and the loader lift cylinders work fine, I'm not sure that either of these are the issue. Plus, the hydraulic filter was replaced at 400 hours.

Anyone have any suggestions on this?

Much appreciated!

- Spindifferent

 

[Eric102]

How about switching the hoses at the hydraulic connectors to see if the problem is in loader side of the disconnects or the tractor side.

 

[arlen4720]

Does the tractor seem labored when you are activating the curl? Does it sound like the hydraulic relief valve is opening? You can "dead head" the loader lift cylinders to see what it sounds like if you don't know what I mean.
You should swap your lift and curl hoses around. That will help isolate the probem. You may have a bad quick coupler.

 

[arlen4720]

How about switching the hoses at the hydraulic connectors to see if the problem is in loader side of the disconnects or the tractor side.

You type faster than me

 

[Spindifferent]

Thanks Eric and Arlen!

I did switch the hydraulic hoses between the lift and bucket cylinders, and the slowness moved to the lift, and the bucket worked just fine. This tells me that all the loader cylinders/lines are working fine, and that there is an issue on the tractor with the yellow and/or red hydraulic lines.

For future reference for anyone who may want to switch the hydraulic hoses between the lift and bucket on a 3520 with 300X, here's what I did:

Tractor Side - Loader Side
Yellow - Black
Red - Green
Black - Yellow
Green - Red

This combination keeps the cylinder rod and head connections inline.

Thanks for your help in troubleshooting. I guess it's time to make an appointment with the dealer for service.

- Spindifferent