S300 Female Auxiliary Coupler Issue

[05sprcrw]

I feel like I am fighting a loosing battle, on trying to figure out why any aux hydraulic attachments will always move on their own. I have singled it down to the female coupler side of the system.

If I start the bobcat and use it there will be no movement of the attachment (like it should). If I energize the aux hydraulics variable flow, it will still be fine, however once I move the attachment the first time it will continue to open (in this case) my grapple. This is pretty annoying trying to keep the brush in the bucket while it keeps wanting to open. It is not like its getting full flow by any means its just creeping up over the matter of 30 seconds for the full range of motion.

Things I have tried, but have not been the answer:
Both new aux valves (stems and coils)
New Aux circuit lockout coil/stem
New aux springs, bushings, caps and seals
New check valve seats, springs and seals
New High Flow solenoid thinking it was not fully staying off/leaking by (high flow deactivated when I bought the machine)

If I unplug the aux coils after it has started its creeping issue, it will continue so I believe it has to be something mechanical within the circuit. I have not tried unplugging the high flow on/off valve yet.

All of these things have been over the last year or so, but its time where I am needing the grapple and tree shear a fair amount and now am really determined to get to the bottom of this issue. I am going to flip my couplers on the grapple for now so it will at least power close but its not idea for getting out and loading branches and things in the grapple while cleaning the yard up from the winter and trimming trees.

I am really at a loss for what to try next, some thoughts are:
New right stick control handle (grasping, but don't think its the issue)
Try a new aux spool (other looks fine no marring)
Remove aux spool and try to install it the opposite way (service manual didn't make it sound like it mattered which way it went back in, and appears the same each way)
Possibly damaged main valve body (hope not,sounds expensive)

The hydraulic circuit diagram in the service manual the only other thing in the female coupler circuit that I haven't looked at would be the relief valves, but since it builds pressure I don't think those would cause this issue.

Any and all ideas/help would be greatly appreciated.

 

[Zewnten]

Sounds like your shuttle isn't returning to center. Try measuring the pilot line pressure at the valve and make sure you don't have anything activated, if that's good I would try replacing the springs, maybe one side is weak? Unless I read wrong and you already did that.

 

[05sprcrw]

That is what I keep feeling is the issue but I have put (2) new sets of the aux springs, bushing and for lack of a better word washer that goes on each end of the valve on the aux circuit. I haven't put a spool in it because it looked good, but I broke down and ordered a new one I figured if I have to go in to measure it at this point I might as well just get a new one and put it in there then I can eliminate that as a possibility as well.

Could a relief be sticking and let fluid back feed the circuit, while the other functions are being used?

 

[Zewnten]

Generally it has been my experience that a relief problem will show itself in the attachment being weak or having low power. Unfortunately I'm still leaning to the spool, or your solenoid that controls pilot pressure isn't working properly

 

[JBrady]

Do you have the deluxe control panel on the right side (the one with a keypad to start machine)? If so, I think you can go in the attachments settings and reconfigure which buttons on the right side control arm do what. That may only work on Bobcat brand attachments, but if you have that ability you might be able to further troubleshoot your problem. Also, I don't mean to insult, but you are operating the grapple from the paddle switch and not the trigger. right? The trigger holds in the aux circuit, as in for augers or cutters.

 

[05sprcrw]

I will check in the control panel (I do have the deluxe) to see if I can reconfigure but I don't remember seeing anything like that in there. I know there is an option to lock out the use of the high flow for sure. Yes I amusing the paddle switch to operate the grapple in either direction.

Once the spool comes in later this week I will hopefully have time to swap that out and do a little more diagnostics over the weekend.

 

[05sprcrw]

Just wanted to update this, the weather finally turned nice so I have been doing some needed dirt work and haven't had time to mess with the aux spool yet. However the machine went down monday night with a blown turbo, so while I am waiting for the turbo to come in, I will look at installing the spool this weekend and hopefully get to test it sometime next week. Still not convinced the spool is the issue but if I was going in there again to swap it around to make sure its not directional I figured kill two birds with one stone.

 

[05sprcrw]

I am back to update this, its not a high priority fix it issue for me but I have narrowed it down to the high flow circuit on the machine. I took and capped off the high flow line from the pump to the check valve on the left side of the machine. This stopped the cylinder creep, so now I either have a bad relief valve, or the coil and stem to turn the high flow on. I put a new coil and stem in earlier in the year and it didn't solve it, so I am ordering a relief valve and for good measure going to put a new check valve in as well. The only other thing if that doesn't stop it I guess I may have to live with it until the pump goes out if something is damaged in the housing. The other thing I am going to check in the next few days is, if the coil is getting some power from a short some where and slightly opening the coil which would let the fluid through as well.

If anyone has any other ideas however it would be appreciated.