Gentlemen good evening! Long time lurker needs some help.
My issue;
I just picked up a Bobcat 331, s/n 234314211, with just shy of 1900 hours on it. I've had an intermittent issue where the boom cylinder refuses to move. Today it was very stubborn, and after a few starts and some troubleshooting, I was able to get it to raise... but it won't go back down. I have no idea why it decided to at least lift this time, but not before.
The first time it did this, I did some searching online and found a post about the pattern changer being between positions. I brought the switch all the way over to ISO and the controls worked fine. This time that simple fix didn't do anything, and I think it might have been coincidence.
My troubleshooting;
- Engine power level doesn't seem to affect the problem
- All other circuits work fine
- machine moves fine
- when moving the joystick to bring up the boom I didn't hear any fluid moving, or relieving, but this machine's hydraulics are pretty quiet, and I'm not used to it
- Switching from ISO to SAE, the problem "switches joysticks." In the ISO configuration the right joystick fails to move the boom, in the SAE configuration the problem moves over to the left joystick.
- when the boom cylinder did lift, it wasn't as smooth as the other circuits; there was a lag in the controls. The right joystick seems like it has a stronger "spring return" feeling to center position, than it does on curl/uncurl or left/right movements.
What I've done to it;
I added a thumb kit to it. The old stick-side flat face quick disconnects were pretty worn and dripping. They just got replaced today. The issue occured prior to thumb kit install, as well. I don't think this is related, unless the air introduced into the lines is somehow causing this problem. Otherwise I've only put about 5 hours on the machine so far, clearing a flat spot in the yard, and picking up a few logs with the thumb.
This is my first excavator, so I'm a bit of a novice, but I have worked with tractors for a while. Any assistance would be greatly appreciated. I'll be sure to post the solution for the next guy.
My thoughts;
- Could the pattern changer have an issue? It's turned all the way over to the contact, and all other inputs work correctly in both patterns.
- The issue jumping between joysticks when I do switch the pattern changer makes me think it is something outside of the low pressure hydraulics, and might be the spool or the cylinder, but this is new to me!
- What does a jammed spool look/feel like? Would a damaged cylinder do something like this?
- After getting home I realized I should have looked to see if the hydraulic lines going to the boom cylinder were "jumping" with the applied pressure when I moved the control stick. If they aren't I can assume the problem is behind them. If they are than I must have a jammed cylinder, right? Like I said above, I didn't hear fluid moving when I made control inputs, but I'm new to this thing.
I'm excited to be told to check something completely obvious that I may have missed. Thanks in advance. Hoping this is a cheap fix, haha.
-- Aaron
My issue;
I just picked up a Bobcat 331, s/n 234314211, with just shy of 1900 hours on it. I've had an intermittent issue where the boom cylinder refuses to move. Today it was very stubborn, and after a few starts and some troubleshooting, I was able to get it to raise... but it won't go back down. I have no idea why it decided to at least lift this time, but not before.
The first time it did this, I did some searching online and found a post about the pattern changer being between positions. I brought the switch all the way over to ISO and the controls worked fine. This time that simple fix didn't do anything, and I think it might have been coincidence.
My troubleshooting;
- Engine power level doesn't seem to affect the problem
- All other circuits work fine
- machine moves fine
- when moving the joystick to bring up the boom I didn't hear any fluid moving, or relieving, but this machine's hydraulics are pretty quiet, and I'm not used to it
- Switching from ISO to SAE, the problem "switches joysticks." In the ISO configuration the right joystick fails to move the boom, in the SAE configuration the problem moves over to the left joystick.
- when the boom cylinder did lift, it wasn't as smooth as the other circuits; there was a lag in the controls. The right joystick seems like it has a stronger "spring return" feeling to center position, than it does on curl/uncurl or left/right movements.
What I've done to it;
I added a thumb kit to it. The old stick-side flat face quick disconnects were pretty worn and dripping. They just got replaced today. The issue occured prior to thumb kit install, as well. I don't think this is related, unless the air introduced into the lines is somehow causing this problem. Otherwise I've only put about 5 hours on the machine so far, clearing a flat spot in the yard, and picking up a few logs with the thumb.
This is my first excavator, so I'm a bit of a novice, but I have worked with tractors for a while. Any assistance would be greatly appreciated. I'll be sure to post the solution for the next guy.
My thoughts;
- Could the pattern changer have an issue? It's turned all the way over to the contact, and all other inputs work correctly in both patterns.
- The issue jumping between joysticks when I do switch the pattern changer makes me think it is something outside of the low pressure hydraulics, and might be the spool or the cylinder, but this is new to me!
- What does a jammed spool look/feel like? Would a damaged cylinder do something like this?
- After getting home I realized I should have looked to see if the hydraulic lines going to the boom cylinder were "jumping" with the applied pressure when I moved the control stick. If they aren't I can assume the problem is behind them. If they are than I must have a jammed cylinder, right? Like I said above, I didn't hear fluid moving when I made control inputs, but I'm new to this thing.
I'm excited to be told to check something completely obvious that I may have missed. Thanks in advance. Hoping this is a cheap fix, haha.
-- Aaron
