1990 John Deere 490D Excavator four roller Fabtec Harvester Hydraulic issue

[CGreenham]

Good Morning,

I have an issue with an older John Deere 490D excavator/tree harvester. It was working fine and all of a sudden a few functions would not work,
- One track drive motor will not work.
- The stick in will not work it will go out but wont come back towards cab.
- The feed roller for the head will spin in one direction but not reverse.


Any idea what the issue could be I haven't looked into the system just wondering were to start, hopefully its not the pump, no issues at all with the machine until this sudden happened.

I was grubbing a road when this happened so maybe a wire off somewhere? Hopefully.

Any advice greatly appreciated I'm not a mechanic and only do this for a hobby.

Thank you all this is a great forum with a wealth of knowledge.

 

[Dave Neubert]

sounds like half of the pump quit

 

[Diesel Dave]

What track drive motor quit ,left or right side ?

 

[CGreenham]

What track drive motor quit ,left or right side ?

It was the right side that wouldn't move. The left side worked strong.

 

[Diesel Dave]

The right side track and the auxiliary function are supplied from different pumps.
I suspect there is a component failing (possibly the right side track motor) sending shrapnel through the entire hydraulic system creating sticking spools in the main control valve and the control valve for the harvester head.
Pull the main hydraulic filter and check for metallic debris.

 

[CGreenham]

The right side track and the auxiliary function are supplied from different pumps.
I suspect there is a component failing (possibly the right side track motor) sending shrapnel through the entire hydraulic system creating sticking spools in the main control valve and the control valve for the harvester head.
Pull the main hydraulic filter and check for metallic debris.

Thanks Dave I will check the filter, that right side motor always seemed weaker then the left side motor.

Sounds better then the main pump gone.

Thanks for your help.

 

[CGreenham]

Hi all,

Found this out this weekend, if I start the machine and shut off the key basically turn off the electronics to the processing head the machine runs fine except for the harvesting head functions. Must be a stuck valve in the head or something, sounds like the machine is underload and two functions are working the same time.

Do you think the check vale would cause this as there is one in the aluminum block in the saw area.


Thanks for your help.

 

[CGreenham]

Just a little update with the machine I found out if you start the machine and turn off the key which sends power to the fabtec head all systems will work except for the head. The machine will not go under load and all system seems fine and it will track good and the stick functions are good. Turn the key on and it goes under load and the problem continues.

Just wondering if any one has experience a similar issue and what was the cause.

Thanks for your help.

 

[Diesel Dave]

I’m not overly familiar with forestry heads but I assume there are solenoid valves for every function ? I suspect a joystick handle switch may be stuck.
With key on engine off ,check for power at the individual solenoids on the head.

 

[CGreenham]

Hello All,

I found the problem it was the saw proximity sensor on the harvester head.


Thank you all for your help.