743b bucket raising and lowering issue

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Tkolandscaping

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Apr 6, 2016
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Hi I am having an issue with my bobcat 743b. I just had the control spool valve rebuilt (with seal lot,balls, and springs from bobcat) by a local hydraulic shop. But I am having an issue with the raising and lowering still. Sometimes it will go up when pressing down and visa versa. And sometimes it will lower very quick and not smooth. Also the peddle does not feel smooth. It feels like something in the spool valve is binding. The issue prior to this was that the bucket was stuck in the raise position and would just go right up when you start it and wouldn't go down. This is when I had a mechanic take out the valve and brough it to the hydraulic shop. The tilt function seems to be working smooth and properly. Thanks
 

mmsllc

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Dec 29, 2015
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I'm not sure if you saying that it is messed up & you want to have a mechanic work on it or if it has been to a mechanic && then this issue has started after the visit to the mechanic?? WHO pulled the valve out? You or the mechanic?? Despite that issue - confusing to read - it sounds like there is something inside of the valve, hence the binding / grinding feel. It could be something small / metallic or just some dirt causing the spools to bind up. I would pull it apart ASAP because prolonged use will only cause more damage, thus cost more money. Take it apart in order to see if it is part of a pump coming apart or just random trash in the hydraulic system.
 
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Tkolandscaping

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I'm not sure if you saying that it is messed up & you want to have a mechanic work on it or if it has been to a mechanic && then this issue has started after the visit to the mechanic?? WHO pulled the valve out? You or the mechanic?? Despite that issue - confusing to read - it sounds like there is something inside of the valve, hence the binding / grinding feel. It could be something small / metallic or just some dirt causing the spools to bind up. I would pull it apart ASAP because prolonged use will only cause more damage, thus cost more money. Take it apart in order to see if it is part of a pump coming apart or just random trash in the hydraulic system.
The issue that caused the bobcat not too function correctly was that the loader arms would be jumpy, sometimes go up when trying to go down. Then the loader arm arms got stuck in the raided position and wouldn't go down. So I traced it back to the control valve spool not retracting. After noticing that I had a mechanic confirm the supposed cause of the issue he took out the control valve and I had brought it to a hydraulic repair shop to have them rebuild it. Once I got it back from the shop the mechanic re-installed it and put in new fluid and filter. Now the loader arms will go up and down but not smoothly. It jumpy like before. Goes up when you want it to go down. And the feels like something in binding as you have to put too much force on it for it too work. Also if you have the bucket raised and the tilt curled backed and go to press the tilt to curl back psst it's return position the loader arms will raise.
 

Tazza

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The issue that caused the bobcat not too function correctly was that the loader arms would be jumpy, sometimes go up when trying to go down. Then the loader arm arms got stuck in the raided position and wouldn't go down. So I traced it back to the control valve spool not retracting. After noticing that I had a mechanic confirm the supposed cause of the issue he took out the control valve and I had brought it to a hydraulic repair shop to have them rebuild it. Once I got it back from the shop the mechanic re-installed it and put in new fluid and filter. Now the loader arms will go up and down but not smoothly. It jumpy like before. Goes up when you want it to go down. And the feels like something in binding as you have to put too much force on it for it too work. Also if you have the bucket raised and the tilt curled backed and go to press the tilt to curl back psst it's return position the loader arms will raise.
Could it be your linkages from the pedal to the control block binding up?
Are the aux hydraulics locked on? grab the right stick, pull it to the left and let it spreng back to neutral.
 

7LBSSMALLIE

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Feb 2, 2012
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1,290
Could it be your linkages from the pedal to the control block binding up?
Are the aux hydraulics locked on? grab the right stick, pull it to the left and let it spreng back to neutral.
tazz right aux stuck. and when you mention hyd shop we cringe. more times than I count same sad story local hyd shop just went thru it rebuilt my whatever cost me whatever. can you please fix it.
 

7LBSSMALLIE

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tazz right aux stuck. and when you mention hyd shop we cringe. more times than I count same sad story local hyd shop just went thru it rebuilt my whatever cost me whatever. can you please fix it.
oh by the way its the detent in aux spool
 
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Tkolandscaping

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Apr 6, 2016
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Ok, thanks. I'll give these suggestions a try.
Ok, I took the linkage for the up/down pedal off and it moves freely when disconnected. I moved the aux controls and that moves freely side to side. And seems to be operating smoothly. The tilt function is operating smoothly. The top spool which controls the up and down is where the issue is. It will go up fine but it seems like you have to find the sweet spot on the pedal for it to lower or else it will keep going up. And the pedal doesn't automatically go back to nuetral. It stay with the pedal pressed down or pressed up until you place oposing force. I am not sure if I should order a new top spool valve, seals, detent, and springs and have just the top valve gone over again. Is this something that can be done with the control valve still installed. I am open to suggestions on what to replace. Hopefully this borrows it down.
 

SkidRoe

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Dec 10, 2009
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Ok, I took the linkage for the up/down pedal off and it moves freely when disconnected. I moved the aux controls and that moves freely side to side. And seems to be operating smoothly. The tilt function is operating smoothly. The top spool which controls the up and down is where the issue is. It will go up fine but it seems like you have to find the sweet spot on the pedal for it to lower or else it will keep going up. And the pedal doesn't automatically go back to nuetral. It stay with the pedal pressed down or pressed up until you place oposing force. I am not sure if I should order a new top spool valve, seals, detent, and springs and have just the top valve gone over again. Is this something that can be done with the control valve still installed. I am open to suggestions on what to replace. Hopefully this borrows it down.
sounds like the return/detent mech is fouled up. sake the cover off the back of the valve for that spool, should be held on with 2 bolts. Get ready for some springs and balls to fly out when you take it off. No need to replace the whole valve, these parts are available. HTH - SR
 

7LBSSMALLIE

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Feb 2, 2012
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sounds like the return/detent mech is fouled up. sake the cover off the back of the valve for that spool, should be held on with 2 bolts. Get ready for some springs and balls to fly out when you take it off. No need to replace the whole valve, these parts are available. HTH - SR
control vale repair on 743 aint fun. removal even worse. but on that happy note. eiser access can be gained by removing eng. its really not that bad to pull. also while its out can inspect and renew whatever is needed . in a perfect world that eng can be on the ground in 2hrs. something to think about .
 

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