aux hydraulics 743

[twest]

I recently bought a grapple bucket for my 743 and have never used aux hydraulics on this machine. grapple of course is hyd open and close. I believe on the 743 that hydrolic flow is only one direction (pressure and return). so i could only close or open depending on line connection. my question is where could I get a 12v valve to reverse flow? that maybe I could mount near quick connecter or near bucket, has anyone done this or have any suggestions? I was thinking this would be easier than removing control valve and trying to replace that spool section with 3 position valve if thats even a option? Thanks in advance for any advice, Tim

 

[Luthor]

The aux. hydraulics on your 743 will work the grapple perfectly just the same as having a 4 in 1 bucket or any other attachment with double acting cylinders.

 

[twest]

The aux. hydraulics on your 743 will work the grapple perfectly just the same as having a 4 in 1 bucket or any other attachment with double acting cylinders.

Ok someone please let me know, when I pull the right steering lever towards me it will clamp grapple down but when i release or put handle back to right it dosent open just stops the flow of oil to the cylinder. I have swaped lines and then it would open but not close. does the 743 only have a pressure and return one direction or am I doing something wrong? Thanks, Tim

 

[jerry]

Ok someone please let me know, when I pull the right steering lever towards me it will clamp grapple down but when i release or put handle back to right it dosent open just stops the flow of oil to the cylinder. I have swaped lines and then it would open but not close. does the 743 only have a pressure and return one direction or am I doing something wrong? Thanks, Tim

If you have removed the stop bolt from the lower right hand stick check back by the valve to see if a hose is interfering with the linkage, on my machine it was and wouldn't go into detent. Tazza will know what is wrong.

 

[twest]

If you have removed the stop bolt from the lower right hand stick check back by the valve to see if a hose is interfering with the linkage, on my machine it was and wouldn't go into detent. Tazza will know what is wrong.

from what I have learned today it is already a 3 position valve on the control valve but its not working like one. I have checked linkage and all seems to be fine not binding or touching anything. the locking bolt for the lever i already removed. dont look like enough travel at spool on control valve unless it dont take much. I have removed the detent section on the rear of that spool and looks like someone has been in there, alot of blue silicon on outside of detent cap also after cleaning i see a small weep hole thru side of cap that I believe should be there to relieve any pressure from oil leaking thru seal on spool. this detent has 10 steel balls and all looked good from what I could tell. I also removed the shaft from that section and all looked clean and strait. after reassembly same problem. and wondering if whoever was in there before put the tapered seat for the detent balls in the right way, as I could never feel it go into detent (even after adjusting) which i believe is toward the right? as the bobcat service manual dosent show much on the control valve. if some one has some info on this please help me out. Thanks, Tim

 

[Tazza]

from what I have learned today it is already a 3 position valve on the control valve but its not working like one. I have checked linkage and all seems to be fine not binding or touching anything. the locking bolt for the lever i already removed. dont look like enough travel at spool on control valve unless it dont take much. I have removed the detent section on the rear of that spool and looks like someone has been in there, alot of blue silicon on outside of detent cap also after cleaning i see a small weep hole thru side of cap that I believe should be there to relieve any pressure from oil leaking thru seal on spool. this detent has 10 steel balls and all looked good from what I could tell. I also removed the shaft from that section and all looked clean and strait. after reassembly same problem. and wondering if whoever was in there before put the tapered seat for the detent balls in the right way, as I could never feel it go into detent (even after adjusting) which i believe is toward the right? as the bobcat service manual dosent show much on the control valve. if some one has some info on this please help me out. Thanks, Tim

Tim - got your e-mail, sorry i didn't post earlier, been a big weekend!
I would suspect there is something stopping the spool from moving all the way back to reverse the oil flow. I have never had a control block with the 10 balls, mine have only ever had 4. It will still operate just fine if you keep them out just to test if that is the problem with binding. The spring will still hold centre but without the balls it will not hold in the detent position. The hole in the cap is factory.
The spool should move the same distance both back and forth, so if you see it pulls forward more than it pushes back something is definitely binding up! You could even remove the cap and see if the flow will reverse, but remember it will NOT return to centre on its own without the cap.

 

[twest]

Tim - got your e-mail, sorry i didn't post earlier, been a big weekend!
I would suspect there is something stopping the spool from moving all the way back to reverse the oil flow. I have never had a control block with the 10 balls, mine have only ever had 4. It will still operate just fine if you keep them out just to test if that is the problem with binding. The spring will still hold centre but without the balls it will not hold in the detent position. The hole in the cap is factory.
The spool should move the same distance both back and forth, so if you see it pulls forward more than it pushes back something is definitely binding up! You could even remove the cap and see if the flow will reverse, but remember it will NOT return to centre on its own without the cap.

Thanks Tazza, I will try that monday to pull the detent balls out and try it or remove the whole cap. I didnt even think to try that and begining to wonder after seeing adjuster nuts on linkage shaft has been rounded that maybe someone has adjusted this to far out to detent. also can you clarify the operation of the aux hyd lever, far right should be detent which is off or no fluid pressure either line? then pulling far left should flow fluid one direction? and release the lever should spring center? then to right a little should reverse flow? Thanks, Tim

 

[Tazza]

Thanks Tazza, I will try that monday to pull the detent balls out and try it or remove the whole cap. I didnt even think to try that and begining to wonder after seeing adjuster nuts on linkage shaft has been rounded that maybe someone has adjusted this to far out to detent. also can you clarify the operation of the aux hyd lever, far right should be detent which is off or no fluid pressure either line? then pulling far left should flow fluid one direction? and release the lever should spring center? then to right a little should reverse flow? Thanks, Tim

You should be able to pull the lever in wards then let it spring back to centre, then you should be able to push it to the right without it touching the frame and if the detent is working you should be able to push it far enough out that it locks in. For normal use you don't push it that far out as to lock it in detent, but you will learn this. As long as the lever is not striking the frame the adjustment of the linkage may be rite, if it is touching you may need to extend it.
The detent actually locks the spool in position so fluid will flow in one direction for attachments. The fluid flow with the aux hydraulics is fully reversible. For my 4 in 1 pull the lever in and the bucket closes, push it out and the bucket opens. It will be the same for your grapple bucket when you get the issues sorted out.