Backhoe I want to dump this in a ditch and start shooting it until it becomes fun LW-7

[johneic]

Boom will not go up
Goes down fine (See pic, please don't laugh in my face)
Three things
1) boom up control valve lever does not fully depress (does not come toward me as if something is preventing it from fully operating the valve).
2) It has lost the "springyness" for up boom, springs fine and returns to neutral for down boom.
3)When I am trying to lift the boom I have only 700psi, If I lightly or fully do dipper retract at the same time I go to 2,200 psi and the boom up worked a few times this way, this no longer works.

I assume something is stuck in the control valve and I have to dissemble it and clean it out, how do I do this?

As the pic shows, its out in the field and I can not move it, I want to loosen the hose at the cylinder (Bottom end-the end towards the operator as it is now) but I am afraid of unreleased pressure, is there a safe way to do this? I would then raise it with another tractor and tie it in up position to get it in the barn.

John

PS I was asked before what my dirt/clay looks like, see pic

 

[Smalljobs]

When my BH was new a few months ago I found something similar: One of the levers was binding. I removed the sheet metal covering the valves and found that one of the plungers was hanging up on the linkage. Unfortunately I deleted the photos I took but it was obvious there was too much play in the linkage. It was easy to remove a cotter pin and mating pin so that I could add a few washers to take up some space.

One joystick operates two valves and the "finger" that ran the adjacent valve plunger was not properly engaged and had allowed the adjacent plunger to rotate about its own vertical axis. The result was that the joystick was hanging up and could not operate the valve.

I'm not sure if your problem is the same, but it's simple to remove the tinware and observe the valve linkage.

At the time this happened to me I learned from my friend, the local Jinma dealer, and also from RonMar, that this my was not unusual.

After shimming the pins and applying Loctite to the threads, I was able to run the hoe for around 40-50 hours with no problems. Today, I removed the hoe for the winter.

 

[biggerten]

I have no specific knowledge to offer to solve this problem, but when I was assembling my LW7 I used a come-along tied to the ROPS to lift the boom. You could then insert the boom pin and drive it away for service.

 

[johneic]

When my BH was new a few months ago I found something similar: One of the levers was binding. I removed the sheet metal covering the valves and found that one of the plungers was hanging up on the linkage. It was easy to remove a cotter pin and mating pin so that I could add a few washers to take up some space.

One joystick operates two valves and the "finger" that ran the adjacent valve plunger was not properly engaged and had allowed the adjacent plunger to rotate about its own vertical axis. The result was that the joystick was hanging up and could not operate the valve

I have removed the top metal-tinwork and looked at the linkages, I see nothing wrong, it appears to me the "plunger" does not go down when activated by the linkages, I may be very wrong here, I have to look again after what you have said, thanks

 

[johneic]

I used a come-along tied to the ROPS to lift the boom. You could then insert the boom pin and drive it away for service.

Alas, I have no ROPS and I have tried many times to get the boom pin in but there are two hoses in the way of the pin and I can not see a way to move them.

 

[johneic]

Note-This is one of many problems over the last six months I have been trying to fix to get this thing to dig.

 

[Smalljobs]

Back to the linkages....look closely at the linkage from another joystick that is working properly and then study the problem one again to see if there is anything different. The plungers rotate and you can move them. When mine was sticking by jamming in the linkage, I rotated the plunger and the problem went away.

 

[Rich Waugh]

If nothing else, you can swap the hoses for the dipper stick and the boom at the control valve and lift the boom using the control circuit for the dipper stick. That may tell you something about the control, too, if the dipper then malfunctions. It does sound to me as though there is a problem with the control valve, probably in the linkage or a piece of crud in the spool plunger.

 

[Bob Rooks]

I had the same problem on my LW-6. Turns out I had blown cup seals in the boom lift cylinder. Everything else worked fine. Not a big job to rebuild the cylinder. Circle-G has rebuild kits for around $25.00.

Note: The new kits have better quality seals.

 

[RonMar]

It could possibly be a combination of issues. There are two parts to a joystick linkage. There is an outer frame that goes from side to side to work the adjacent spool valve(boom swing). There is an inner part that goes for-aft to work the spool that is under the gimbal(boom up/dn). Here is the funny part. The pins that the outer gimbal frame pivot on are vital for the for-aft axis to function. If one of the pivots has come loose, trying to pull the joystick for boom up will instead of pushing the spool down, only tilt the outer frame up. So work the joystick and see what the outer frame is doing. You can also try pushing down on top of the spool and outer gimbal frame with a wrench while trying to work the lever

As mentioned, try taking out the inner gimbal, comes right out by removing the cross pin that runs right under the joystick lever, and try rotating the spool with a wrench. If the spool is frozen, they are easy enough to work on, the top or bottom retainer caps are held in place with 4 allen head machine screws once the gimbal is out of the way...

Another option for getting the beast back in the barn is to disconnect the two hoses for the boom up/dn where they attach at the valve, and connect them to another spool that is working, like bucket curl or an outrigger once lifted off the ground, and try and lift/stow the boom for transit that way... If the boom is firmly on the ground pressure shouldn't be a problem, wear gloves and safety glasses and loosen the fittings slowly to relieve any small ammount of pressure the boom circuit may still be holding...