Tilt spool valve help, any o-rings? What could bind in there?

[kilohertz]

Hi guys,

Still working on my 863 AHC issues and I have narrowed it down to the actual hydraulic control valve. I haven't taken it apart yet and would like to know from someone who has, what could possibly be binding or jamming in there, keeping the actuator from moving. The actuator has such little power compared to a machine with foot pedals, which is a direct mechanical connection to the hydraulic valve spool, and you would never know if something was sticky or binding in the valve with foot pedals, but the poor little actuator only has limited power.

Are there o-rings on the spool? I don't see anything in the parts manual. What else is in there that could occasionally jam up? Piece of dirt? Schmutz, etc? I see 3 different coloured spools in the parts manual, are there different versions for different actuators, or foot pedals? Could the spring be too stiff, maybe wrong one installed at the factory?
Any help from someone who has disassembled the hydraulic control valve would be greatly appreciated. Machine will be back in my shop this weekend.

Cheers

 

[BC873G]

Hey kilohertz, I recently had my spool rods out of the control value on an 873G. There are no o-rings on those spool rods just the seals on each end. My end caps (engine side of the hyd control valve) were painted green. The rods are also stamped on one end and when you order seals the parts match up to the color and stamp. You might have mentioned in a different thread what your issue is. It is locking out when you operate the tilt? Are you operating both the lift and tilt and the same time when it happens? I seem to recall in that thread that you had the actuator off. Were you able to push the spool rod in and check that it is returning to netural? Is the end cap tight on the spool rod? Mine was really loose when I when to remove it. BTW, this is BC873G from the HeavyEquipmentForum. If you want to see pictures of my spool rods while I had them out of the hyd control value. Let me know and I will figure out how to get it to you. Cheers from Kansas Steve

 

[kilohertz]

Hey kilohertz, I recently had my spool rods out of the control value on an 873G. There are no o-rings on those spool rods just the seals on each end. My end caps (engine side of the hyd control valve) were painted green. The rods are also stamped on one end and when you order seals the parts match up to the color and stamp. You might have mentioned in a different thread what your issue is. It is locking out when you operate the tilt? Are you operating both the lift and tilt and the same time when it happens? I seem to recall in that thread that you had the actuator off. Were you able to push the spool rod in and check that it is returning to netural? Is the end cap tight on the spool rod? Mine was really loose when I when to remove it. BTW, this is BC873G from the HeavyEquipmentForum. If you want to see pictures of my spool rods while I had them out of the hyd control value. Let me know and I will figure out how to get it to you. Cheers from Kansas Steve

Hi Steve,
Thanks for the help. Yes, same guy, same problem with the AHC....only tilt problems, never coded on the lift circuit, even after I swap the actuators, wiring, joysticks etc, it's always, physically the tilt valve. My thinking is that something is in there causing the spool to bind. I went thru all the invoices again and the entire control valve was resealed about 2 years ago, running time about 200 hours ago. This is why I think it is in the control valve block, and not really an actuator/wiring/controller problem. I got the machine back to my shop but haven't gone under the cab to look at the end cap or take the spools out.
Quick question, do I need to drain the hydraulic system to take out one spool?
My other thought is, hydraulic fluid....when I accidentally dumped the whole contents into the belly when I had the actuators out last time, I replaced it with AW68, which is all I had, but now looking at the manual, see it should be either 10W30 or AW32 or 46. Also, in the last few days, it's been 25-30C here and it's not cooling off at night, and the machine has been perfect....leads me to think also a temperature issue, oil viscosity issue, or maybe it's my shoe size or the phase of the moon.....that's why the fellow sold it, he had chased this issue for 7 years and $10K and gave up.
Cheers

 

[BC873G]

Hi Steve,
Thanks for the help. Yes, same guy, same problem with the AHC....only tilt problems, never coded on the lift circuit, even after I swap the actuators, wiring, joysticks etc, it's always, physically the tilt valve. My thinking is that something is in there causing the spool to bind. I went thru all the invoices again and the entire control valve was resealed about 2 years ago, running time about 200 hours ago. This is why I think it is in the control valve block, and not really an actuator/wiring/controller problem. I got the machine back to my shop but haven't gone under the cab to look at the end cap or take the spools out.
Quick question, do I need to drain the hydraulic system to take out one spool?
My other thought is, hydraulic fluid....when I accidentally dumped the whole contents into the belly when I had the actuators out last time, I replaced it with AW68, which is all I had, but now looking at the manual, see it should be either 10W30 or AW32 or 46. Also, in the last few days, it's been 25-30C here and it's not cooling off at night, and the machine has been perfect....leads me to think also a temperature issue, oil viscosity issue, or maybe it's my shoe size or the phase of the moon.....that's why the fellow sold it, he had chased this issue for 7 years and $10K and gave up.
Cheers

Hi, I didn't drain the hydraulic system when I took my spools out. I made 4 plugs to insert to help hold the oil in and that worked with minimal success. I put a pan under the drain hole in the belly to catch the lost fluid so it didn't run out on the shop floor. It looked like about 1/2 liter of fluid or so. I remember that you have some sort of steam cleaner so the fluid in the bottom of your machine could easily be flushed. Before I put my spools back in I used break cleaner and a clean cotton rag to clean them up and then applied some assembly lube to the spools. Before you pull the spool clean up around the end cap as much as possible to reduce the chances of picking up any grime that is in the area when you put the spool back in. It's kind of a blind shot inserting the spool back in. The tilt is a bit easier than the lift though. I made good use of an inspection mirror to help get on the those 3/16 hex bolts. I have the long (6 inches, I think) hex ball socket bits that work really well with both the front and back hex bolts. I don't know about the aw68 but doesn't seem like that would be the issue. Steve ps. I saw you grow hops. Hope you are making some good brew those.