Loader/3rd function problem

CGMKCM

Active member

Equipment
RVT-1100C, ZD323, L4760
Jan 26, 2021
411
199
43
Randolph county N.C.
Had a big storm roll through a few days ago that dropped five trees in a big clump, blocking one of my trails. I had the grapple mounted and everything was working great. On the last log I had a problem crop up. I was closing the grapple on a log that was very large on one end and about 1/2 size on the other end. I picked up on the log and it came out of the grapple. After that happened I lost all use of the grapple (open/close) the loader up down was super slow and the three point was also very slow. I lowered the throttle to idle and got off of the tractor to see if I could find any damage. I did not see anything wrong but did hear the sound of a hydraulic restriction from the 3rd function valve located next to the fuel tank. The metal lines were also hot to touch. I drove the tractor to my shop to investigate the problem. I disconnected the 3rd function lines using the quick connects next to the loader. I also removed the cover from the 3rd function control valve and disconnected two plugs that went to the solinoids on either end of the valve body. I then reconnected the plugs, and started the tractor. The loader up down issue and 3 point problems were fixed and no more sound of hydraulic restriction. So the only remaining problem is the 3rd function does not seem to be working at all. The light comes on for the joystick mounded switch that powers the 3rd function. The rocker switch that is used to open and close the grapple is not doing anything. I removed the grapple and connected my 4 in 1 bucket and the 3rd function did not work. Has anyone had similar problems and if so what was the fix? Tractor and I assume 3rd function are under warranty, but if I can save a trip to the dealer, that would be nice.
 

TheOldHokie

Well-known member
Lifetime Member

Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Apr 6, 2021
8,754
4,491
113
Myersville, MD
windyridgefarm.us
Had a big storm roll through a few days ago that dropped five trees in a big clump, blocking one of my trails. I had the grapple mounted and everything was working great. On the last log I had a problem crop up. I was closing the grapple on a log that was very large on one end and about 1/2 size on the other end. I picked up on the log and it came out of the grapple. After that happened I lost all use of the grapple (open/close) the loader up down was super slow and the three point was also very slow. I lowered the throttle to idle and got off of the tractor to see if I could find any damage. I did not see anything wrong but did hear the sound of a hydraulic restriction from the 3rd function valve located next to the fuel tank. The metal lines were also hot to touch. I drove the tractor to my shop to investigate the problem. I disconnected the 3rd function lines using the quick connects next to the loader. I also removed the cover from the 3rd function control valve and disconnected two plugs that went to the solinoids on either end of the valve body. I then reconnected the plugs, and started the tractor. The loader up down issue and 3 point problems were fixed and no more sound of hydraulic restriction. So the only remaining problem is the 3rd function does not seem to be working at all. The light comes on for the joystick mounded switch that powers the 3rd function. The rocker switch that is used to open and close the grapple is not doing anything. I removed the grapple and connected my 4 in 1 bucket and the 3rd function did not work. Has anyone had similar problems and if so what was the fix? Tractor and I assume 3rd function are under warranty, but if I can save a trip to the dealer, that would be nice.
If I understand everything now works except for the third function cylinder. Have you checked the operation of the spool in the third function valve? It sounds like it is not shifting in response to the electrical controls. Depending on model you may be able to manually operate the spool via a threaded hole on the ends of the spool. You can also remove the couplers on the end of the hoses going to the cylinder and put them in a bucket to see if you get oil flow when you press the buttons.

Should be pretty easy to diagnose. May have fried a coil or roached the valve when things got stuck. Neither one is break the bank expensive. New valve is $100-$150 and an hour to swap and coils a lot less.

Dan
 
  • Like
Reactions: 1 user

MidwestMike

New member

Equipment
B2650
Sep 12, 2019
15
6
3
Coloma, MI
As said, you can manually operate most electric valves. In this common example, the point here can be pushed in with a small tool or nail.

If the valve is working, next is to check for power to it.

It could be power supply, shifter-switch, DIN connections to the solenoid, or the solenoid. Work from either direction to see where the issue is. See if you have voltage at the switch first, or check that you have voltage at the solenoid, then work backwards. In this example the DIN connector comes off with one Phillips screw, you can look there first to see if it is time to order a solenoid. If you have this same common valve, I can also double check polarity of the terminals for you if you want to jump the valve with 12 volts.
SpoolSolenoid.jpg
 
  • Like
Reactions: 1 user

CGMKCM

Active member

Equipment
RVT-1100C, ZD323, L4760
Jan 26, 2021
411
199
43
Randolph county N.C.
Follow up on my original post, in case someone searches on this problem in the future.

I transported tractor to Kubota dealer and they were able to get it right into the shop.

They found remnants of a plastic port cover in the main spool valve. The debris bound the valve and the hydraulic pressure was locked in the return fluid position. Basically there was no pressure and volume available to make the loader and 3 point go up/down. They disassembled valve and cleaned everything up and reassembled.
Note-They were not the dealer I purchased tractor from and did not throw Kubota or the dealer I purchased tractor from under the bus. They stated that problem should not have happened and the plug should have been removed prior to installation.