L785 slow boom and bucket. Aux hydraulic ?

[JWD]

Hello- I just bought a L785 this morning that the boom and bucket operate slowly on the drive seems to work fine. The guy I bought it from said it was working fine and he let another guy use it and then it suddenly started messing up. It does have auxiliary hydraulics. I've noticed that the lever for the auxiliary hydraulics is very stiff but if I move the lever all the way up or all the way down the boom and bucket operate correctly but the machine makes a different sound like a pump running. The lever was in the middle position when I got it and thats where the boom and bucket are slow but I don't get the pump running sound. What position should the lever be in for proper boom and bucket operation with nothing hooked up to the auxiliary? Previous owner replaced fluid and filters. This machine also has some added on hydraulic stuff to run a planer that he said was on there when he bought it and he never messed with. I wish to eventually remove this stuff and put things back to the way they would have been originally to simplify things. Thanks for any help you may be able to provide.

 

[Mike10]

Check that the output line from the hyd pump goes to the boom and bucket control valve first. The sound you hear is probably the relief valve opening since you are dead heading the hyd oil until you activate one of the pedals. The handle should be in the middle position.

 

[JWD]

Check that the output line from the hyd pump goes to the boom and bucket control valve first. The sound you hear is probably the relief valve opening since you are dead heading the hyd oil until you activate one of the pedals. The handle should be in the middle position.

I will check this in the morning and report back. Thank You!

 

[JWD]

I will check this in the morning and report back. Thank You!

I pulled the seat and had a look. The first place the hose runs from the pump is a square block on the left side that looks like a distribution block. I got the operators manual when I bought the machine and the inside of my cab is allot more cluttered than the one pictured. I'm gonna try and post a picture of what I've got.

 

[JWD]

I pulled the seat and had a look. The first place the hose runs from the pump is a square block on the left side that looks like a distribution block. I got the operators manual when I bought the machine and the inside of my cab is allot more cluttered than the one pictured. I'm gonna try and post a picture of what I've got.

 

[JWD]

 

[Mike10]

Where do the two hoses go which are attached to the valve with the rod for a handle on the first photo.

 

[JWD]

Where do the two hoses go which are attached to the valve with the rod for a handle on the first photo.

I will find out tomorrow and report back. I also ordered a parts manual today so that I can try and determine what is original and what has been added on. Thank You!

 

[Ivan]

I will find out tomorrow and report back. I also ordered a parts manual today so that I can try and determine what is original and what has been added on. Thank You!

Where are you lines to hook up attachment on the arm or in the cab?

 

[JWD]

Where are you lines to hook up attachment on the arm or in the cab?

they are on the arms and look like they came with the machine.

 

[Ivan]

they are on the arms and look like they came with the machine.

OK I have the block like yours but mine has the shut off built in the block and my lines are inside the cab That is why I was asking as arms will not work when the lines are activated

 

[JWD]

 

[JWD]

 

[JWD]

Is the pump supposed to have 2 inlets and 2 outlets? Mine appears to but the replacement pumps I seen online looked to be 1 inlet 1 outlet.

 

[JWD]

Is the pump supposed to have 2 inlets and 2 outlets? Mine appears to but the replacement pumps I seen online looked to be 1 inlet 1 outlet.

 

[Mike10]

The hyd pump does not look oem. It is hard to tell what exactly was modified from the photos. For the hyd to work as they are supposed to the flow from the pump goes to the boom and bucket control valve first. When the oil exits this valve the oil goes to the aux valve on the right. From there the oil goes to the oil cooler. Your description sounds like the flow is being diverted to the in port of the aux valve and when you dead head the hyd of the aux valve, pressure builds back to the boom and bucket control valve. Have you tried turning the rod handle on valve. It appears to be a flow control valve and it may be sending the flow back to the return.

 

[JWD]

The hyd pump does not look oem. It is hard to tell what exactly was modified from the photos. For the hyd to work as they are supposed to the flow from the pump goes to the boom and bucket control valve first. When the oil exits this valve the oil goes to the aux valve on the right. From there the oil goes to the oil cooler. Your description sounds like the flow is being diverted to the in port of the aux valve and when you dead head the hyd of the aux valve, pressure builds back to the boom and bucket control valve. Have you tried turning the rod handle on valve. It appears to be a flow control valve and it may be sending the flow back to the return.

I'll give that a try with the rod handle on the valve. I'm working on drawing up a diagram illustrating the different parts and how they are hooked up so that maybe I can better show you what I'm working with. This is all new stuff to me. Thanks

 

[JWD]

I'll give that a try with the rod handle on the valve. I'm working on drawing up a diagram illustrating the different parts and how they are hooked up so that maybe I can better show you what I'm working with. This is all new stuff to me. Thanks

I'm still working on this. somebody forced a screw in the valve with a rod for the handle, presumably to keep it from being moved and it's not wanting to come out without a fight. I've got a pretty good start on the diagram but an artist I am not! Might be a few more days on that it's pretty much dark by the time I get home from work.

 

[Ivan]

I'm still working on this. somebody forced a screw in the valve with a rod for the handle, presumably to keep it from being moved and it's not wanting to come out without a fight. I've got a pretty good start on the diagram but an artist I am not! Might be a few more days on that it's pretty much dark by the time I get home from work.

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