763H Aux and lift issue

[Tonka Toy]

Hi all, Got a weird issue with my 763H. Never used the Aux since Ive had it, hooked up my 4 in 1 bucket to it this afternoon, hit the variable/max flow button for Aux, pulled trigger on right hand control and engine booged down but nothing, so played with the 3 switch's on the front, when i used middle toggle switch the pipe from the rear of the pump moves like its getting pressure, but nothing happens after. Traced pipes and found what i think is the two valve coils, one looked ok when i removed it, didn't remove the stem as no idea how but cleaned the shaft, the 2nd, more towards the front of the machine looked rusty, took it off and filled with rust inside, so ok could poss be that, gonna order a new one if i cant get it clean again. Dropped cab thought i'd give it one more quick toggle thru, selected the Aux button, worked them through again and nothing, the arms were raised a little so went to drop them and they raised. pulled trigger on right control again arms dropped ok, deselected the Aux button, engine bogged down again, lifted arms and tried to drop them again and again lifted, have to have the aux button selected to behave normally, Please for my sanity with this machine can someone shed some light on this for me before i take a few gallons of fuel and a match to it Thanks Jon

 

[Tazza]

As you mention it bogs down, it sounds like the stems are functioning but the oil isn't getting to the 4 in 1. Can you trace the lines from the control block back to the quick couplers? check that there is no diverter in the line, i have a 753 that had one, so oil was being dead headed.
If you take the stems out and swap them fron to back, you can see if the issue moves.
When not used for a long time, the stems can get stuck, i managed to free mine up by disassembling it and using WD40, worked a treat.

 

[Tonka Toy]

As you mention it bogs down, it sounds like the stems are functioning but the oil isn't getting to the 4 in 1. Can you trace the lines from the control block back to the quick couplers? check that there is no diverter in the line, i have a 753 that had one, so oil was being dead headed.
If you take the stems out and swap them fron to back, you can see if the issue moves.
When not used for a long time, the stems can get stuck, i managed to free mine up by disassembling it and using WD40, worked a treat.

Hey Tazza, Took the stems out and swapped them over which seems to have done something as now the trigger button when pulled doesn t seem to bog the machine down. Still no flow to the 4 in 1, have you got a dummys guide to cleaning the stems up? After swapping the stems round i now can't lower the lift arms, heel down and lifts, toe down and it still lifts, and nothing i can do seems to bring them back down.

 

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Hey Tazza, Took the stems out and swapped them over which seems to have done something as now the trigger button when pulled doesn t seem to bog the machine down. Still no flow to the 4 in 1, have you got a dummys guide to cleaning the stems up? After swapping the stems round i now can't lower the lift arms, heel down and lifts, toe down and it still lifts, and nothing i can do seems to bring them back down.

because when you are pulling the trigger it's closing the bucket, and its already close, to operate the bucket you should be using the thumb switch on the top of the right stick

 

[Tonka Toy]

because when you are pulling the trigger it's closing the bucket, and its already close, to operate the bucket you should be using the thumb switch on the top of the right stick

Hi Tom, Swapped the Aux stems around and nothing happened, cracked the couplers off and no oil to the couples at all. Would like the Aux to work but the more concerning issue I've got is the way the arms rise no matter what way you push the peddle, unless the Aux flow is selected and the trigger on the right control is pulled. Don't want to burn up a coil or the machine if something is shorting, Machine is a 763H advantage series if that helps any? Thanks Jon

 

[Tonka Toy]

Hi Tom, Swapped the Aux stems around and nothing happened, cracked the couplers off and no oil to the couples at all. Would like the Aux to work but the more concerning issue I've got is the way the arms rise no matter what way you push the peddle, unless the Aux flow is selected and the trigger on the right control is pulled. Don't want to burn up a coil or the machine if something is shorting, Machine is a 763H advantage series if that helps any? Thanks Jon

Well an update. My machine has two sets of Aux hook ups, one with the usual 2 hook ups and one with 3 hook ups. I stupidly assumed the 4 in 1 should be hooked up to the hook up with just 2 couplers. Traced the lines from the block as Tazza suggested and found they went to the side with 3 hook ups, Swapped the couplers over and can now see the line charging when i push the right hand control one way, but nothing in the other, will try swapping Auix stems over and see if it changes when it stops raining. The tilt and lift functions are still playing up, if i push fully on the lower for the boom it will go down but if i try to push it down slowing it lifts, then push fully down and drops, Tilt off works without issue on, but tilt back and it won't unless you use the Aux toggle switch then it works fine. Have read on here the aux stems are very fragile, will try and source some new ones if the swap later tonight changes what is happening. Thinking either short somewhere or a stuck valve.

 

[Tazza]

Well an update. My machine has two sets of Aux hook ups, one with the usual 2 hook ups and one with 3 hook ups. I stupidly assumed the 4 in 1 should be hooked up to the hook up with just 2 couplers. Traced the lines from the block as Tazza suggested and found they went to the side with 3 hook ups, Swapped the couplers over and can now see the line charging when i push the right hand control one way, but nothing in the other, will try swapping Auix stems over and see if it changes when it stops raining. The tilt and lift functions are still playing up, if i push fully on the lower for the boom it will go down but if i try to push it down slowing it lifts, then push fully down and drops, Tilt off works without issue on, but tilt back and it won't unless you use the Aux toggle switch then it works fine. Have read on here the aux stems are very fragile, will try and source some new ones if the swap later tonight changes what is happening. Thinking either short somewhere or a stuck valve.

They are fragile, but that doesn't mean you can't open them up. If your up for an experiement, and know which one is not working right, you have nothing to loose.
Remove the Orings from the end, use soft jaws in a vice and grab ths part that had the orings, use a spanner on the hex part and un-do it. Remove the spool, spring and shims, ensure they move freely, clean with solvent and lubircate with oil or WD40, re-assemble and hopefully it will work again.
When i got my S150 it had sat for a while, one stem was not working, i did the above and it has worked flawlessly for a good 15 years, even has proportional control and that works just right too. If the stem is bad now, you can't make it worse by trying, it will only save you a few hundres bucks on new stems if it works.