Float position detent on lift arm valve.

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Luthor

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Does anyone know the procedure to adjust this detent? My 743 does not lock in.
 

Tazza

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I'm not sure if the 743 series do indeed have a “float” position on the lift arm spool valve.
If i push my toe rite down, i only hear the oil by-passing through the relief vavle....
If it indeed does have a detent setup, it may be worn, or if the previous owner has fiddled with it, it may be missing a few steel balls that are used to lock it in detent.
I will have a squiz at my manual and let you know.
 

goodtech

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Nov 22, 2005
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There is no float adjustment on 743. What usually happens is the balls in the back of the spool get rusted and they don't work anymore. The easiest way to fix this is put your lift arms up, put in your safety stop. unhook the bar off the front of the valve on your lift arm spool go to the back of the machine and reach in there. I usually use a 2ft extention on a allen socket, take the two allen head screws out of the back of the body push the spool out of the front and pull spool and detent assembly out together. then pull your detent assembly slowly apart and watch for flying balls. there should be two springs and 4 balls. if you need to replace them make sure you buy about ten balls and a couple extra springs, there cheap and I you will loose a couple when assembling. but see if that helps you out at all. if you have anymore problems with the assembly let us know. good luck
 

Tazza

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There is no float adjustment on 743. What usually happens is the balls in the back of the spool get rusted and they don't work anymore. The easiest way to fix this is put your lift arms up, put in your safety stop. unhook the bar off the front of the valve on your lift arm spool go to the back of the machine and reach in there. I usually use a 2ft extention on a allen socket, take the two allen head screws out of the back of the body push the spool out of the front and pull spool and detent assembly out together. then pull your detent assembly slowly apart and watch for flying balls. there should be two springs and 4 balls. if you need to replace them make sure you buy about ten balls and a couple extra springs, there cheap and I you will loose a couple when assembling. but see if that helps you out at all. if you have anymore problems with the assembly let us know. good luck
I had a fiddle with my other 743 today (bob 2.0), it does indeed lock into detent when you push the peddle rite down.
Now, to fix it, as goodtech said, they can rust in place or the previous owner had a fiddle and lost a spring or some balls. One other thing you may need is the housing that they run may be worn (that cylinder that sits over the centring spring assembly on the spool valve). I found on my 731 that where the steel balls ran in that housing had worn 4 grooves and it would not hold in the detent position. You may need to buy a new one or machine a new one and harden it.
The “float” position releases the hydro pressure to the lift arms rite? please correct me if i'm wrong, as i have always thought that it did but have never had a machine that actually did it, well not one thats currently working.
 

Luthor

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I had a fiddle with my other 743 today (bob 2.0), it does indeed lock into detent when you push the peddle rite down.
Now, to fix it, as goodtech said, they can rust in place or the previous owner had a fiddle and lost a spring or some balls. One other thing you may need is the housing that they run may be worn (that cylinder that sits over the centring spring assembly on the spool valve). I found on my 731 that where the steel balls ran in that housing had worn 4 grooves and it would not hold in the detent position. You may need to buy a new one or machine a new one and harden it.
The “float” position releases the hydro pressure to the lift arms rite? please correct me if i'm wrong, as i have always thought that it did but have never had a machine that actually did it, well not one thats currently working.
Thanks for the replies guys. I have had the detent assembly apart and found it to be in very good condition except for slight flat spots on balls, which have been replaced. Goodtech, you mentioned removing the spool from the front but can it also be removed by pushing it out the back way with the detent assy attatched? Will I lose all my Hydraulic oil by removing spool?
 

Tazza

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Thanks for the replies guys. I have had the detent assembly apart and found it to be in very good condition except for slight flat spots on balls, which have been replaced. Goodtech, you mentioned removing the spool from the front but can it also be removed by pushing it out the back way with the detent assy attatched? Will I lose all my Hydraulic oil by removing spool?
You can only remove the spool from the back. The manual says NOT to disassemble the spring unless it is broken. Even then, you need to have the spool out and clamp it in a vice to un-do the bolt holding the spring on, this is all under pressure, don't mess with it unless you have a broken spring, they are a horrible thing to re-attach. You have to fight the pressure of the spring and turn a bolt at the same time.
I think goodtech was refering to the fact you need to remove the linkages from the front to pull it out the back, make sure you give it all a good clean before you pull it through, you don't need dirt inside the spool acting as sand paper. It also wouldn't hurt to mark the top and bottom, so you know what way to put it back in. This is not critical, but it wouldn't hurt.
Also, when you do remove the spool, change the 2 O rings, one on the front, one on the back, you don't want any leekage because you disturbed the seals. I know, they are really hard to get to but if you can get to them without toooo much effort do change them.
As for oil, unfortunatly you will get alot of oil pouring out, it doesn't come out that fast, but you will loose quite a bit!, goodtech may know how to slow it down a bit.
 

sterlclan

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You can only remove the spool from the back. The manual says NOT to disassemble the spring unless it is broken. Even then, you need to have the spool out and clamp it in a vice to un-do the bolt holding the spring on, this is all under pressure, don't mess with it unless you have a broken spring, they are a horrible thing to re-attach. You have to fight the pressure of the spring and turn a bolt at the same time.
I think goodtech was refering to the fact you need to remove the linkages from the front to pull it out the back, make sure you give it all a good clean before you pull it through, you don't need dirt inside the spool acting as sand paper. It also wouldn't hurt to mark the top and bottom, so you know what way to put it back in. This is not critical, but it wouldn't hurt.
Also, when you do remove the spool, change the 2 O rings, one on the front, one on the back, you don't want any leekage because you disturbed the seals. I know, they are really hard to get to but if you can get to them without toooo much effort do change them.
As for oil, unfortunatly you will get alot of oil pouring out, it doesn't come out that fast, but you will loose quite a bit!, goodtech may know how to slow it down a bit.
hook a shop vac to the hydralic oil filler and duct tape the hose on and run the vac now when you open the valve the oil is under suction and it shouldnt leak much have all your stuff ready cause the vac will puke if left on too long oh yea take out that paper filter in the vac first
 

goodtech

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Nov 22, 2005
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112
You can only remove the spool from the back. The manual says NOT to disassemble the spring unless it is broken. Even then, you need to have the spool out and clamp it in a vice to un-do the bolt holding the spring on, this is all under pressure, don't mess with it unless you have a broken spring, they are a horrible thing to re-attach. You have to fight the pressure of the spring and turn a bolt at the same time.
I think goodtech was refering to the fact you need to remove the linkages from the front to pull it out the back, make sure you give it all a good clean before you pull it through, you don't need dirt inside the spool acting as sand paper. It also wouldn't hurt to mark the top and bottom, so you know what way to put it back in. This is not critical, but it wouldn't hurt.
Also, when you do remove the spool, change the 2 O rings, one on the front, one on the back, you don't want any leekage because you disturbed the seals. I know, they are really hard to get to but if you can get to them without toooo much effort do change them.
As for oil, unfortunatly you will get alot of oil pouring out, it doesn't come out that fast, but you will loose quite a bit!, goodtech may know how to slow it down a bit.
A shop vac works great but if you are like me I can't stand hearing the damn things run for hrs. so What i do is unhok the suction line really quick and end up shoving a #12 or #14 jic plug in the hose and put the clamp back on it. that way you will only loose what is in the lift arms and in the valve which really isn't to much. I'm sorry if I confused you on which way that spool has to come out, pull it out the back, watch for the orings and seals. Make sure you put the same color seals back in it. Bobcat kits come with three colors and they are all close, the wrong one and it will puke on you in about a hr of running it. Most bobcat techs hang on the kits, so if you take some doughnuts or pizza down they can usually find some seals for you. otherwise you are going to have to buy the kit. Bobcat does make there own valves so it is really hard for a hydraulic shop to match up the seals, the orings they can...Good luck
 

goodtech

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Nov 22, 2005
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A shop vac works great but if you are like me I can't stand hearing the damn things run for hrs. so What i do is unhok the suction line really quick and end up shoving a #12 or #14 jic plug in the hose and put the clamp back on it. that way you will only loose what is in the lift arms and in the valve which really isn't to much. I'm sorry if I confused you on which way that spool has to come out, pull it out the back, watch for the orings and seals. Make sure you put the same color seals back in it. Bobcat kits come with three colors and they are all close, the wrong one and it will puke on you in about a hr of running it. Most bobcat techs hang on the kits, so if you take some doughnuts or pizza down they can usually find some seals for you. otherwise you are going to have to buy the kit. Bobcat does make there own valves so it is really hard for a hydraulic shop to match up the seals, the orings they can...Good luck
Sorry guys, I meant the suction line coming from the tank to the pump. I usually unhook from the pump and throw my plug in there.
 

Luthor

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Nov 15, 2005
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176
Sorry guys, I meant the suction line coming from the tank to the pump. I usually unhook from the pump and throw my plug in there.
I have worked out why I can't lock the detent in. The accumulation of wear on the lever arm that goes from the left hand side of the machine , under the front hydrostatic pump, and over to the lift valve, is not allowing full pedal travel to be transmitted to the spool. It appears that the bushing hole in the lever is worn as well as the bush itself allowing about 2mm of play at the pivot point. Now I have to work out how to get the lever out so I can make new bushes etc.
 

Tazza

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I have worked out why I can't lock the detent in. The accumulation of wear on the lever arm that goes from the left hand side of the machine , under the front hydrostatic pump, and over to the lift valve, is not allowing full pedal travel to be transmitted to the spool. It appears that the bushing hole in the lever is worn as well as the bush itself allowing about 2mm of play at the pivot point. Now I have to work out how to get the lever out so I can make new bushes etc.
Joy oh joy!

Doing that is a horrible job, i did it on mine when the engine was out. I un-did the 4 bolts holding the hydrostatic pump in place and some levers to get under it and removed it. THEN i had to machine new parts for it to run in, they run a nylon bushing that wears the steel pin that it moves on. It is very easy to fix, but access is really bad. Hopefully goodtech has some tricks up his sleeve :)
 

Luthor

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Nov 15, 2005
Messages
176
Joy oh joy!

Doing that is a horrible job, i did it on mine when the engine was out. I un-did the 4 bolts holding the hydrostatic pump in place and some levers to get under it and removed it. THEN i had to machine new parts for it to run in, they run a nylon bushing that wears the steel pin that it moves on. It is very easy to fix, but access is really bad. Hopefully goodtech has some tricks up his sleeve :)
I have finally got the float position detent working. By making new slightly oversize clevis pins to suit holes in lever and spool attatchments to remove excess play and by moving the pedal slightly forward I can now lock in the detent. I would still like to remove the lever and rework it to eliminate excess play at its pivot point but that may have to wait.
 

goodtech

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Nov 22, 2005
Messages
112
Joy oh joy!

Doing that is a horrible job, i did it on mine when the engine was out. I un-did the 4 bolts holding the hydrostatic pump in place and some levers to get under it and removed it. THEN i had to machine new parts for it to run in, they run a nylon bushing that wears the steel pin that it moves on. It is very easy to fix, but access is really bad. Hopefully goodtech has some tricks up his sleeve :)
Well I have no tricks up my sleeve for that one. It is just time to get down and dirty and fix the the bushing problem, sorry guys I have no tricks to help ya out on that one. Have fun.
 

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