L785 slow boom and bucket. Aux hydraulic ?

[JWD]

I was wondering why that screw was in there. It looks like the handle will not move with it there

Ivan. Does your machine have the extra mesh filter on the floor or the lines teed off of the auxiliary control valve like mine.

 

[Ivan]

Ivan. Does your machine have the extra mesh filter on the floor or the lines teed off of the auxiliary control valve like mine.

No Mine has block like the one on yours but there is a difference as my has 2 lines coming out the top with quick disconnects on it. On my block there is a control valve built right in the block. If the lines are acivated my boom will not work. The one picture that you have of a valve I think it is as Mike said a flow control valve. Look at the lines and see if the block is make as where the lines go. I have one on the elevator for my wood processor and I think one line goes in and where it comes out is the power out the 3rd line is a tank return. By moving the handle on this valve I can control the elevator speed. That ois why I asked why the screw was in there. It may be such a thing as you move the handle everything may start working. I think as Mile said it is bypassing to your tank now with out a load on it

 

[JWD]

No Mine has block like the one on yours but there is a difference as my has 2 lines coming out the top with quick disconnects on it. On my block there is a control valve built right in the block. If the lines are acivated my boom will not work. The one picture that you have of a valve I think it is as Mike said a flow control valve. Look at the lines and see if the block is make as where the lines go. I have one on the elevator for my wood processor and I think one line goes in and where it comes out is the power out the 3rd line is a tank return. By moving the handle on this valve I can control the elevator speed. That ois why I asked why the screw was in there. It may be such a thing as you move the handle everything may start working. I think as Mile said it is bypassing to your tank now with out a load on it

Thanks! I got the screw out right about dark and the lever won't move by hand gonna have to try a cheater pipe tomorrow. I'm hoping for some decent weather this weekend so I can get out the pressure washer and clean this thing up. I think it will make it easier to figure out what all the lines are running to.

 

[JWD]

Thanks! I got the screw out right about dark and the lever won't move by hand gonna have to try a cheater pipe tomorrow. I'm hoping for some decent weather this weekend so I can get out the pressure washer and clean this thing up. I think it will make it easier to figure out what all the lines are running to.

That lever won't move! I leaned on it hard enough that the rod started to bend. I started the machine and the boom and bucket was acting the same way.I went to move the machine and the right side didn't want to go! That's a first! No lights were on so I let it idle for a couple minutes and then it would drive good like before. I decided to pull the mesh strainer that's under the seat and check it out. Previous owner said he replaced it and it looks brand new. The oil however is foamy! I mean foamy like the head on a beer foamy! The parts manual showed up today so I'll be studying that tonight. Let me know what you think about this foamy oil. Thanks again guys

 

[JWD]

That lever won't move! I leaned on it hard enough that the rod started to bend. I started the machine and the boom and bucket was acting the same way.I went to move the machine and the right side didn't want to go! That's a first! No lights were on so I let it idle for a couple minutes and then it would drive good like before. I decided to pull the mesh strainer that's under the seat and check it out. Previous owner said he replaced it and it looks brand new. The oil however is foamy! I mean foamy like the head on a beer foamy! The parts manual showed up today so I'll be studying that tonight. Let me know what you think about this foamy oil. Thanks again guys

 

[JWD]

 

[JWD]

Here's what I came up with so far on diagram. still working and cleaning on this thing.

 

[deaop06]

Here's what I came up with so far on diagram. still working and cleaning on this thing.

JWD, I don't know about your machine but I have a l555D. I have done a lot of small things to it. Fixed leaks, new hoses and rebuilt both lift rams. The one thing I have learned is if it won't work take it apart and find out why. If it was me I would take that valve off take it apart and find out why it won't move. The auxiliary valve cable on mine was broken when I got it. The valve was stuck and would not move. I took it apart and it was very dirty and crusty inside. Cleaned it good and installed new cable and it works great now. These machines were well built and everything can be fixed. You just need a lot of patience to work on them. Get the books, parts manual, service manual and owners manual. Then do a lot of reading. I hope you luck with your problem. You will have a great machine when it starts working. Ron

 

[Mike10]

Here's what I came up with so far on diagram. still working and cleaning on this thing.

You left out the boom and bucket control valve and plumbing.

 

[JWD]

You left out the boom and bucket control valve and plumbing.

I know. Hopefully I'll get that part mapped out tomorrow it's been a little harder for me to trace out. I didn't get to work on it any at all today. Thanks

 

[JWD]

You left out the boom and bucket control valve and plumbing.

 

[JWD]

Here's what I came up with for a hydraulic diagram. I appreciate everyone's help.

 

[Mike10]

Here's what I came up with for a hydraulic diagram. I appreciate everyone's help.

All the added parts are to convert the standard hyd flow loader to a hi-flow machine. The problem rests in the adjustable flow control valve. Oil flows to the least resistence, so if the that valve is turned to supply oil to the axu vavle the oil more or less free flows back to sump. When you deadhead the aux valve oil pressure builds backwards through the flow control valve and then to the tee at the distribution box and to the boom and bucket valve. That is why the boom and bucket will work then. You need to determine how to stop the flow from the flow control valve, red handle valve, to the aux valve. ...The big question is what role the distribution block actually plays.....Just looking at the diagram you would think you could plug all three lines at the flow control valve and that would solve the problem.....The problem arises there is no pressure relief valve until the oil reaches the boom and bucket control valve, so if flow is blocked before that point, you will blow the hyd pump up.... I do not think that would happen, but can not be certain.

 

[Mike10]

All the added parts are to convert the standard hyd flow loader to a hi-flow machine. The problem rests in the adjustable flow control valve. Oil flows to the least resistence, so if the that valve is turned to supply oil to the axu vavle the oil more or less free flows back to sump. When you deadhead the aux valve oil pressure builds backwards through the flow control valve and then to the tee at the distribution box and to the boom and bucket valve. That is why the boom and bucket will work then. You need to determine how to stop the flow from the flow control valve, red handle valve, to the aux valve. ...The big question is what role the distribution block actually plays.....Just looking at the diagram you would think you could plug all three lines at the flow control valve and that would solve the problem.....The problem arises there is no pressure relief valve until the oil reaches the boom and bucket control valve, so if flow is blocked before that point, you will blow the hyd pump up.... I do not think that would happen, but can not be certain.

A standare flow control valve has three ports like the one in the diagram, The pressure in port, the pressure out port, and the excess flow port. When the valve is turned to cut the flow to the aux valve, or to slow the flow, all the excess oil will go through the excess flow port back to sump, or in this case to the distribution block.

 

[JWD]

A standare flow control valve has three ports like the one in the diagram, The pressure in port, the pressure out port, and the excess flow port. When the valve is turned to cut the flow to the aux valve, or to slow the flow, all the excess oil will go through the excess flow port back to sump, or in this case to the distribution block.

Mike10 Thank You for the detailed description. I'm feeling like it may be beneficial to remove the flow control valve and distribution block from the machine and see about getting the valve to move like was recommended earlier and determine just what's going on in the distribution block. Would you agree that it would be a good next step to take? I can't help but think that the flow control valve has been in it's current position for quite some time being that it won't move and it had that screw forced in there to prevent it's movement.

 

[Mike10]

Mike10 Thank You for the detailed description. I'm feeling like it may be beneficial to remove the flow control valve and distribution block from the machine and see about getting the valve to move like was recommended earlier and determine just what's going on in the distribution block. Would you agree that it would be a good next step to take? I can't help but think that the flow control valve has been in it's current position for quite some time being that it won't move and it had that screw forced in there to prevent it's movement.

I think the first thing I would do is remove the hose from the flow control to the aux valve and plug the fitting at the aux valve. Have a 5 gal bucket ready to put the end of the hose into and momentarilly start the engine and see if there is a large amount of flow coming out of the hose. That will tell you if the flow control valve is open and allowing oil to flow to the aux valve instead of the control valve. I do not think I would remove the distribution block. You might also remove the hose at the top right on your drawing of the distribution block and the lower left and blow air into the top right and see if it comes out the lower left without any restriction. I would think it would but there is only one way to know for sure. If air passes without restriction, then just plug the ports on the distribution block which go to the flow control valve and the fitting at the aux valve which will allow you to remove the flow control valve.

 

[JWD]

I think the first thing I would do is remove the hose from the flow control to the aux valve and plug the fitting at the aux valve. Have a 5 gal bucket ready to put the end of the hose into and momentarilly start the engine and see if there is a large amount of flow coming out of the hose. That will tell you if the flow control valve is open and allowing oil to flow to the aux valve instead of the control valve. I do not think I would remove the distribution block. You might also remove the hose at the top right on your drawing of the distribution block and the lower left and blow air into the top right and see if it comes out the lower left without any restriction. I would think it would but there is only one way to know for sure. If air passes without restriction, then just plug the ports on the distribution block which go to the flow control valve and the fitting at the aux valve which will allow you to remove the flow control valve.

Alright I'm gonna get set up to try this and I'll let you know how it goes.

 

[JWD]

Alright I'm gonna get set up to try this and I'll let you know how it goes.

Well it may be Friday or Saturday before I get to mess with this anymore. I have come up with a couple questions though. What role does the flow control valve play? Is it to completely direct flow in one direction or another or is it used to adjust the amount of flow somewhere in between? Can the auxiliary hydraulics be used at the same time as the boom/bucket functions on these machines? Some of what I've read I have understood to mean you have to select between auxiliary function or boom/bucket function. Thanks

 

[Mike10]

Well it may be Friday or Saturday before I get to mess with this anymore. I have come up with a couple questions though. What role does the flow control valve play? Is it to completely direct flow in one direction or another or is it used to adjust the amount of flow somewhere in between? Can the auxiliary hydraulics be used at the same time as the boom/bucket functions on these machines? Some of what I've read I have understood to mean you have to select between auxiliary function or boom/bucket function. Thanks

The flow control valve is to control the speed of an attachment. On a stock machine the oil flow goes to the boom and bucket control valve first so if you activate the boom or bucket it will slow or stop the aux hyd tool. On your machine you have basically a double pump since you have two inlets and two outlets with each set going to a separate valve. In theory you can operate each at the same time, however, if you have a high flow tool the speed could change when operating the boom or bucket. It will not stop since you have a separate oil circuit, but if you look at the diagrams you drew, the outlet of the boom and bucket valve goes to the aux valve to increase the flow to the tool.

 

[JWD]

I think the first thing I would do is remove the hose from the flow control to the aux valve and plug the fitting at the aux valve. Have a 5 gal bucket ready to put the end of the hose into and momentarilly start the engine and see if there is a large amount of flow coming out of the hose. That will tell you if the flow control valve is open and allowing oil to flow to the aux valve instead of the control valve. I do not think I would remove the distribution block. You might also remove the hose at the top right on your drawing of the distribution block and the lower left and blow air into the top right and see if it comes out the lower left without any restriction. I would think it would but there is only one way to know for sure. If air passes without restriction, then just plug the ports on the distribution block which go to the flow control valve and the fitting at the aux valve which will allow you to remove the flow control valve.

OK. I removed the hose from the flow control valve to the aux. valve and plugged the fitting at the aux. valve. started the engine and nothing came out at all. I removed the hose from the distribution block that comes from pump outlet #2 in my diagram and the hose from the tee on the distribution block that runs to the boom/bucket control valve and air blows through freely.