bucket position valve

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bluffcam

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Oct 6, 2007
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rebuilding an 843 with isuzu engine. got machine together with new u-joint and a rebuilt hydrostatic pump. Can't get bucket hydraulics to work. I can raise bucket with machine running but only lower it with machine off and pedal in certain position and it will bleed down slowly. the tilt will tilt completely down but not up. I tool off the bucket position valve and took it apart. nothing looked out of sorts to me, cleaned it up and put it back on with same result. I think it may be this valve because the only function that doesn't go thru this valve is the up lift function and that works. I am considering bypassing this valve with some fittings to see if that is indeed the problem. Any ideas or experience ?
 

Tazza

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I have never used a bucket positioning valve, but i understand how they work. It shouldn't be causing you these problems though as it works by directing different percantages of flow between cylinders. Have you bled your hydraulic system? It could be air still stuck in the system causing a few problems, but i doubt its the main cause.
Have you checked the linkages too? as you said you need to get the pedal in just the rite spot for it to bleed down.
 

Fishfiles

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I have never used a bucket positioning valve, but i understand how they work. It shouldn't be causing you these problems though as it works by directing different percantages of flow between cylinders. Have you bled your hydraulic system? It could be air still stuck in the system causing a few problems, but i doubt its the main cause.
Have you checked the linkages too? as you said you need to get the pedal in just the rite spot for it to bleed down.
My first thought , would be the aux hydraulics sticking , then the detent of the float on back of the spool came apart and has it jammed up , or it broke the stud which holds the centering spring on the back of the spool
 

skidsteer.ca

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My first thought , would be the aux hydraulics sticking , then the detent of the float on back of the spool came apart and has it jammed up , or it broke the stud which holds the centering spring on the back of the spool
Sounds like Aux hydraulics to me too. Make a loop hoes and connect you front quick coupler line together. If the problem goes away thats your culprit.
Ken
 
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bluffcam

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Oct 6, 2007
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Sounds like Aux hydraulics to me too. Make a loop hoes and connect you front quick coupler line together. If the problem goes away thats your culprit.
Ken
he haw, thanks a bunch, put a loop hose on and works fine.
now for the detent aux valve fix---when i had the engine and hydraulic pumps out I found I could not pull the right lever left or right to run aux hydraulics. i pulled the back cap off and the spool valve moved freely, I didn't see anything obvious so I put it back together stuck. Any way to fix this detent easily or does the whole valve need to come out?
thanks again for the help, it saved me a ton of time.
 

Tazza

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he haw, thanks a bunch, put a loop hose on and works fine.
now for the detent aux valve fix---when i had the engine and hydraulic pumps out I found I could not pull the right lever left or right to run aux hydraulics. i pulled the back cap off and the spool valve moved freely, I didn't see anything obvious so I put it back together stuck. Any way to fix this detent easily or does the whole valve need to come out?
thanks again for the help, it saved me a ton of time.
*slaps forehead* i thought it was a newer machine that has electro-mechanical valves. I really should read the posts more.
You shouldn't need to pull the control block for this. It should simply be stuck in detent position. If all the linkages are still attached just grab the right steering stick and pull it all the way to the left and let it spring back to centre. It should be quite stiff to get it to pop out of detent mode.
You said you removed the back cap on the control block, did any metal balls fly out? there should have been a spring with 2 balls that are used to hold the spool in detent when engaged or did you just remove the cover? Could you see the entire spring? or was it covered with a metal cup?. Hopefully its just a metal ball has slipped out causing it to lock in detent.
 

OldMachinist

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May 24, 2006
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he haw, thanks a bunch, put a loop hose on and works fine.
now for the detent aux valve fix---when i had the engine and hydraulic pumps out I found I could not pull the right lever left or right to run aux hydraulics. i pulled the back cap off and the spool valve moved freely, I didn't see anything obvious so I put it back together stuck. Any way to fix this detent easily or does the whole valve need to come out?
thanks again for the help, it saved me a ton of time.
You said that you couldn't move the lever left or right. Maybe the lock bolt is still in place that comes from factory or the cable is froze up.
 

sterlclan

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May 1, 2004
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You said that you couldn't move the lever left or right. Maybe the lock bolt is still in place that comes from factory or the cable is froze up.
I used some head tube bearings from a 10 speed bicycle to replace the detent springs on mine mine was stuck like yours and can be repaired in the machine not easy but possible...........Jeff
 

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