CTL 70 accessory Hydraulics not holding?

[Rio_Grande]

Wondering if anyone has any experience with this. I have a ctl70 by Ghiel. Over the last few months the accessory hydraulics have started to loose their hold. I use a grapple bucket on the system and previously I would close the grapple and it would hold that pressure until I released it. Now it will not hold and I can hear fluid bypassing loudly when I hold the button down and for a few seconds after I release it. I also noticed when I hold the button down I seem to loose alot of power in motion that diddnt happen before.

I asume something has gone wrong with the hydraulic valve that this controls but is there any other possibilites? I am due for a fluid change and the only thing we have been doing diffrent recently is running a brush cutter which does get the fluid much hotter than normal.

Thanks for any help you can provide.

 

[Rio_Grande]

bump.

 

[woodlandfarms]

I am going to say you have some fouling in the valve of either the control or the rod. Lots of other possibilities. If you want to truly diagnose before you get into it, get yourself a pressure reader (build one). Think of it like electricity. You would use a volt meter to find the short. It is the same thing but with a pressure reader.

 

[IceStationZebra]

If I interpreted the parts manual correctly, the aux valve is the top section of the main control valve. It is a spool valve actuated by pilot lines, which are pressurized through an electric valve which is close to the main valve. The electric valve is controlled electrically by your joystick, though I don't know if a relay is in the circuit.

So your problem could be with either the main spool valve or the electric valve. From your description it sounds like one of the valves is hanging up. The correct way to diagnose it is as Woodlandfarms recommends, with a pressure gauge. I would check the pilot line first to see if it is bleeding down right away after you release the button. If it does than your spool valve is at fault, if not the solenoid valve is the culprit. (If you are lucky you might be able to observe the hoses moving to see if there is pressure.)

If you don't have a gauge, first see if you get the same behavior when you try to pressurize the grapple in the open direction. If you do than the problem is most likely with the spool valve. Take the spool out and check for debris and free movement. If not it is probably the solenoid valve. You could try swapping the solenoids valve and see if the problem follows the valve. (swap the coil and poppet as a unit) There is also the slim possibility that the electrical is hanging up. (Be aware that this is not the preferred method because there is a greater risk to contaminate the system.)

In either case, please be safe and don't work under raised arms or try to bypass the safeties.

FYI - The Gehl CTL70 is the same machine as a Mustang MTL20, and very similar to a Takiuchi TL140.

ISZ

 

[Rio_Grande]

Thanks, I am going to roll the cab and see what I can come up with. I don't have much experience working on my machine. I hope I can resolve it without getting too crazy. We are almost completely out of work and we can't pay to have it repaired. Hope it is something simple.

 

[Rio_Grande]

ISZ from looking at the scam tics, can I take the cartridge out of that valve and clean it ? I have fixed valves in the past by taking them apart and cleaning them, adding new o rings and the like, is that what I am looking at here or something different?

 

[J_J]

When the valve is in neutral, the spool closed and there might be some pressure, but it will probably bleed off with time.

I believe I would put a gage in the circuit and take some readings first.

The relief valve may be fouled or the spools leaking..

If the hyd system is open center, then all valves are in series.

 

[Rio_Grande]

Thanks JJ buddy of mine said he would show me how to build a gauge. He said he has done it before.

 

[J_J]

I should have posted some hyd gage test sets.

Uses a 3000 psi liquid filled gage .

Cost about $30

 

[Rio_Grande]

I cant build one cheaper than that where did it come from?

I get how to check it at the outlets but do I remove a hose near the valve and put it inline to test there?