Need constant flow

[NCDiesel]

Hey folks, I have a mid 90s 753. The hydraulics have always worked for implements where I want to be able to operate them using that dumb switch on the right control lever. However I just got a log splitter, and need constant flow, like a back-hoe. According to my owners manual I hit the hydraulic button twice to get both lights, hit the trigger switch on the right control lever, and this puts it in "detent" position. I should have constant flow at this point and be able to operate the log splitter using the control valve on the splitter itself. However this does not seem to work. The log splitter operates fine using the thumb switch, but I want to be able to operate the log splitter alone so I need that constant flow. Is there any troubleshooting I can do to narrow the problem? Is it a new control lever knob time? Am I doing something wrong? Thanks in advance for all the advice and opinions

 

[bobbie-g]

Seems to me you are doing everything correctly. Not sure what you are referring to as the "dumb switch?" From my recollection on my machines, once you press the hydraulic button twice and have both lights, depressing the trigger switch should give you flow, but in one direction only. If you want flow in the other direction, you have to first move the bi-directional switch one way, hold it there, and depress the trigger. Then flow should be locked in whatever direction the thumb toggle was depressed. Same thing for moving the thumb toggle the other way with trigger action, so you should be able to get continuous hydraulic flow in either direction by first pressing the thumb toggle in that direction then actuating the trigger. Can't tell ya how to know which direction is which, just try 'em both. Oh, I think the lap bar has to be down to keep both hyd LEDs on??? I usually use my hydraulics with a snow blade, can't remember how it worked with the backhoe. Been too long....... --- Bobbie-G

 

[NCDiesel]

Seems to me you are doing everything correctly. Not sure what you are referring to as the "dumb switch?" From my recollection on my machines, once you press the hydraulic button twice and have both lights, depressing the trigger switch should give you flow, but in one direction only. If you want flow in the other direction, you have to first move the bi-directional switch one way, hold it there, and depress the trigger. Then flow should be locked in whatever direction the thumb toggle was depressed. Same thing for moving the thumb toggle the other way with trigger action, so you should be able to get continuous hydraulic flow in either direction by first pressing the thumb toggle in that direction then actuating the trigger. Can't tell ya how to know which direction is which, just try 'em both. Oh, I think the lap bar has to be down to keep both hyd LEDs on??? I usually use my hydraulics with a snow blade, can't remember how it worked with the backhoe. Been too long....... --- Bobbie-G

Thanks Bobbie G Dumb switch=thumb switch. I was doing voice-to -text to compose the message and didn't notice it changed the word on me. I did try several combinations of thumb switch and trigger actions and nothing. The other clue I have is the "unlock" light on the control panel right behind the operators right arm flashes when I hit the trigger. Otherwise I got no other clues to work with. Thanks again, Spencer

 

[bobbie-g]

Thanks Bobbie G Dumb switch=thumb switch. I was doing voice-to -text to compose the message and didn't notice it changed the word on me. I did try several combinations of thumb switch and trigger actions and nothing. The other clue I have is the "unlock" light on the control panel right behind the operators right arm flashes when I hit the trigger. Otherwise I got no other clues to work with. Thanks again, Spencer

Spence, I was incorrect about one thing. Just checked with my grapple, the flow will only lock in one direction. Moving the thumb switch to the left then clicking the trigger will not lock the flow in that direction. Only the right thumb direction plus trigger locks. Unsure why your BICS light would flash, but that might be a clue to something. ---Bobbie-G

 

[NCDiesel]

Spence, I was incorrect about one thing. Just checked with my grapple, the flow will only lock in one direction. Moving the thumb switch to the left then clicking the trigger will not lock the flow in that direction. Only the right thumb direction plus trigger locks. Unsure why your BICS light would flash, but that might be a clue to something. ---Bobbie-G

Thanks. I replaced the right hand controller and wiring because I was getting 2-3 ohms across wires that should be basically zero when the trigger is pressed. But that did not help. I guess I need to look at the aux hydraulics solenoid wiring next.....

 

[NCDiesel]

Thanks. I replaced the right hand controller and wiring because I was getting 2-3 ohms across wires that should be basically zero when the trigger is pressed. But that did not help. I guess I need to look at the aux hydraulics solenoid wiring next.....

OK - so I was able to check the resistance of the solenoids on the control valve - both are 10.5Ohms. Never could find a specification for them but the fact that both are identical means both are good or both are bad. Since the thumb paddles work, my guess is both are good. Where do I go next for troubleshooting?

 

[NCDiesel]

OK - so I was able to check the resistance of the solenoids on the control valve - both are 10.5Ohms. Never could find a specification for them but the fact that both are identical means both are good or both are bad. Since the thumb paddles work, my guess is both are good. Where do I go next for troubleshooting?

Good news and bad. Good news is it is fixed. Bad news is I never could troubleshoot this myself. Had to send it to the dealer who said the wiring was "wrong". I didn't ask any further but I suspect near the controller where I saw some previous owners had spliced some stuff and it looked, shall we say, less than professional. I haven't lifted the cab and pulled the seat to see what they might have done. My next question is: Can the flow direction of continuous flow be reversed in a mid-90s Bobcat 753? My log splitter operates in reverse(have to use "retract" to "advance" the ram and vice-versa). I can't believe the manufacturer of the log splitter reversed the connectors on the hoses or the ports on the control valve since they sell so many. But they must have as I have also always heard that continuous flow on this era of bobcat always operated in continuous flow in one direction only. Thanks in advance!

 

[jimmythegreek]

Good news and bad. Good news is it is fixed. Bad news is I never could troubleshoot this myself. Had to send it to the dealer who said the wiring was "wrong". I didn't ask any further but I suspect near the controller where I saw some previous owners had spliced some stuff and it looked, shall we say, less than professional. I haven't lifted the cab and pulled the seat to see what they might have done. My next question is: Can the flow direction of continuous flow be reversed in a mid-90s Bobcat 753? My log splitter operates in reverse(have to use "retract" to "advance" the ram and vice-versa). I can't believe the manufacturer of the log splitter reversed the connectors on the hoses or the ports on the control valve since they sell so many. But they must have as I have also always heard that continuous flow on this era of bobcat always operated in continuous flow in one direction only. Thanks in advance!

I believe u can simply switch hose ends to swap flow direction or do the whole hose if that's easier and will work normal for u

 

[Tazza]

I believe u can simply switch hose ends to swap flow direction or do the whole hose if that's easier and will work normal for u

I'd swap the couplers too.

 

[NCDiesel]

I'd swap the couplers too.

I actually did try that, but the couplers on the hoses from the splitter are gender specific. So you can't swap. I thought maybe the other end of the hoses wouldn't be, but I was wrong there also. Since I posted this, i asked the service manager of the bobcat shop that did the repair about it. He indicated he thought there was a way to reverse the continuous flow on this machine but was unfamiliar enough with this vintage to be sure or was aware of the exact procedure. So any hints or tips would be appreciated. I tried different combinations of thumb paddles and trigger pulls to no avail.

 

[walio123]

I actually did try that, but the couplers on the hoses from the splitter are gender specific. So you can't swap. I thought maybe the other end of the hoses wouldn't be, but I was wrong there also. Since I posted this, i asked the service manager of the bobcat shop that did the repair about it. He indicated he thought there was a way to reverse the continuous flow on this machine but was unfamiliar enough with this vintage to be sure or was aware of the exact procedure. So any hints or tips would be appreciated. I tried different combinations of thumb paddles and trigger pulls to no avail.

Just change the positions of the solenoids, this should reverse the direction of the flow.

 

[walio123]

Just change the positions of the solenoids, this should reverse the direction of the flow.

The other simple option is to tighten with a rubber band trigger or tape it in the direction you need.