My TL240 hydraulic quick attach is not working properly, and I could use some help diagnosing. The cylinder retracts (unlocks the quick attach) just fine. When I go to lock the attachment in, the cylinder moves for a split second and stops. When trying to lock, the engine does not labor when you hold the button like it does the other direction. I removed the cylinder from the assembly to test it alone and had the same issue. Here is everything I've tried/tested: Switched the hydraulic lines at the outputs of the valve body. This reversed my issue - it would then extend just fine, but only retract for a moment. Made sure each solenoid was receiving power when the appropriate lock/unlock button was pressed - each was holding roughly 12V. I confirmed continuity on the ground side. Backprobing the connectors, I see a 10.8v drop across each solenoid while holding their respective buttons down. Checked resistance across each solenoid - each measured around 9 ohms, which I believe is the correct spec. Switched the electrical connections to the solenoids. This also reversed my issue to the other direction. What's next to troubleshoot? Is this enough info to confirm a bad valve body? If it is a bad valve body, can they be rebuilt or does it need to be replaced? Thanks for any help!
If you swapped the electrical connections and it reversed the problem, then it would appear that both the solenoids and the valve are functioning properly. I would look at the control switch
I'm confused. can you share some photos? i have added this , if you want to check it out.
That's what I thought, but how would I go about further troubleshooting the control switch? It's supplying correct voltage to the appropriate solenoid when the switch is pressed/held. I'm certainly no electronics wizard, so any guidance would be appreciated.
The bottons that you press to control the quick attach would be suspect. Have you disconnected them under the pilot controls and checked them for continuity while holding the button. Is there any change?
Based on the previous troubleshooting, I figured the switch had to be good. However, having nothing left to try, I did isolate and troubleshoot the switch today. It's working correctly. I located and purchased the solenoids on the valve body just to try swapping a relatively cheap part. Wired them in and have exactly the same issue. Not really surprised - just another data point.
I would say that it must be in the hydraulic line that you have isolated as not having pressure after a few moments. Internal collapse after getting pressure?
When I switch the hydraulic lines to the cylinder, the problem reverses to the other direction. Would it still do that if it was an issue with one of the lines? I'm getting a bit out of my lane here - I'm no mechanic. If it helps at all, when I push the button to the direction that doesn't work, I don't think the hydraulic line actually pressurizes. The engine doesn't labor, the lines don't jump, etc. It seems more like it's just removing pressure from the other side, which results in a tiny movement at the cylinder. Thanks for your help so far, by the way. I appreciate it!
If the solenoid is new and sending the correct magnetic field to the valve/poppet, then i would say that valve is not opening. That’s why it’s not pressurizing that line. I would look at the hose routing to that valve block.
I forgot to update this thread. I threw in the towel and called a local mechanic. He found a wiring diagram and located a relay between the control switch and the solenoid valve. There was a diode with that relay that went bad. I don't feel so bad though, as it took him quite a while to figure it out and mentioned it was one of the more difficult diagnostics he's had to do.