Backhoe boom struggles to go up, drops when feathering up

[oldnslo]

Yes that's the only one. Rest of the backhoe seems to function as it should. The loader also works like it should

Since just that function I would look closely at that particular valve spool and linkage assembly to confirm nothing is loose or something jammed limiting spool travel.

Do you have access to a schematic for that back hoe valve? If yes that could provide some insight on other things to consider.

 

[dodge man]

I agree on unplugging and plugging back in any quick connects for the hydraulics. Sometimes they look connected but aren’t quite right.

 

[dirtyb115]

Since just that function I would look closely at that particular valve spool and linkage assembly to confirm nothing is loose or something jammed limiting spool travel.

Do you have access to a schematic for that back hoe valve? If yes that could provide some insight on other things to consider.

Only schematic that i can find is in the operator manual. (See attatched)

 

[oldnslo]

Thanks for posting the schematic. If it is accurate there are no load checks shown on any of the functions which I suspect is inaccurate but not an unusual occurrence to see general schematic vs detailed.
Is the valve accessible so that you can take some pictures of it? Someone might recognize it and be able to state there are load checks under these plugs.

 

[dirtyb115]

Thanks for posting the schematic. If it is accurate there are no load checks shown on any of the functions which I suspect is inaccurate but not an unusual occurrence to see general schematic vs detailed.
Is the valve accessible so that you can take some pictures of it? Someone might recognize it and be able to state there are load checks under these plugs.

Here is what it looks like

 

[oldnslo]

Dirtyb
In looking at those pictures of the valve it appears there is a plug between the work ports. I suspect that is the load check for each spool. If you are comfortable working on this I believe below that plug would be spring and either a check ball or poppet. After making 100% certain that the backhoe is in relaxed position I.e. all pressure removed, try removing the plug on the spool section that is failing and inspect that check assembly. Poppet stuck, piece of crud on seat, etc.

 

[dirtyb115]

Dirtyb
In looking at those pictures of the valve it appears there is a plug between the work ports. I suspect that is the load check for each spool. If you are comfortable working on this I believe below that plug would be spring and either a check ball or poppet. After making 100% certain that the backhoe is in relaxed position I.e. all pressure removed, try removing the plug on the spool section that is failing and inspect that check assembly. Poppet stuck, piece of crud on seat, etc.

Thanks for the suggestion, I'll take a look tomorrow if I have time. Appreciate the help

 

[dirtyb115]

Dirtyb
In looking at those pictures of the valve it appears there is a plug between the work ports. I suspect that is the load check for each spool. If you are comfortable working on this I believe below that plug would be spring and either a check ball or poppet. After making 100% certain that the backhoe is in relaxed position I.e. all pressure removed, try removing the plug on the spool section that is failing and inspect that check assembly. Poppet stuck, piece of crud on seat, etc.

Had a chance to take a look tonight. I pulled the plug, and as you suspected a spring/poppet. When i took it out the poppet stayed in the bore, and was sideways, but I am not sure if it was like that or it happened when i took the plug out. At any rate, i cleaned the seat, but didn't notice anything obvious. I don't think it fell over while reassembling, but having the valve block laying flat would make it a lot easier.

I started it up, and operated it a little in the barn, It was way better than before, but did notice it falling every once in a while when lightly lifting. (Maybe air still in the system? ).

With everything fully extended, it was still struggling to bring the boom all the way up, i had to curl it in before i could fully raise the boom. I did get my pressure gauges and fittings. Where should i be checking the pressure?
Thanks again for the help.

 

[oldnslo]

In looking at the valve pictures you posted it looks like there might be a plug that is connected to the “P” port. It is on right side valve in photo showing two sections and the “P” stamp on the casting. You could use that port or tee the gauge into the P line. This will provide pressure reading for all the functions. Run one function to end of stroke get reading, next, etc.

Looking at the complete valve photo The 2nd and 5th function might have work port reliefs. These are the silver hex fitting above the hose connection. They might be set lower than system relief so don’t panic if they show a lower pressure.

 

[dirtyb115]

In looking at the valve pictures you posted it looks like there might be a plug that is connected to the “P” port. It is on right side valve in photo showing two sections and the “P” stamp on the casting. You could use that port or tee the gauge into the P line. This will provide pressure reading for all the functions. Run one function to end of stroke get reading, next, etc.

Looking at the complete valve photo The 2nd and 5th function might have work port reliefs. These are the silver hex fitting above the hose connection. They might be set lower than system relief so don’t panic if they show a lower pressure.

Ok thanks hopefully I'll find some time this week to take a look. Also not sure if it's related but I have noticed that the boom wants to drop really fast if I'm not easy with the controls. Not sure if that's normal or not