Valve control unit on a LA681 FEL

[elvira]

Hello All. My first post after a few weeks of reading. I have a Kubota L4310 tractor with a LA681 FEL. The FEL has a remote valve control unit which is operated - via cables - by a control lever on the RHS mudguard. The operation of the bucket is smooth, but the operation of the lever for the boom is a jerking movement and needs to be pushed back into neutral. It feels as if there is something broken which is grinding in the control valve for the boom only.
Would someone be able to guide me in the right direction as to how to go about investigating this problem. Perhaps even be able to provide a workshop how to dismantle/repair this valve control unit. All ideas welcome.

Thanks, elvira

 

[kennyd]

Welcome to TBN

My :2cents: says a cable is your problem. Try unhooking them and see if they move freely. Like bicycle cables and parking brake cable on cars/trucks they are prone to rusting/corroding on the inside and causing problems. There is not a whole lot in a valve that can go bad.

 

[elvira]

Welcome to TBN

My :2cents: says a cable is your problem. Try unhooking them and see if they move freely. Like bicycle cables and parking brake cable on cars/trucks they are prone to rusting/corroding on the inside and causing problems. There is not a whole lot in a valve that can go bad.

Thanks for the advise. I took the cables out as they were tight and suspect, so I cleaned and oiled them as much as I could. The inner cable does not come out at all. Pulling either way didn't make any difference. The cable moves about 4" both ways. After re-assembling, the same grinding noise was still there. It appears that that is not the problem. I then pulled and pushed on the valve control rods which gave the same grinding sound/feeling as with the cable connected. Therefore, unfortunately, it must be the control valve. As explained in my first post, any idea as to the best way to tackle this problem. Your advice is much appreciated.

elvira

 

[kennyd]

Sorry that didn't work, now onto the valve. On the opposite end of where the cables attach should be a "cup" for lack of a better word, it houses the detent balls for the float option on the valve. The spool moves in/out of this cup everytime the valve/spool moves. There is usuallt two Alan head cap screws holding this cup in place. It is not uncommon for this cup to hold moisture, and then the balls get rusty. You will need to remove it carefuly so as not to loose any balls/parts and clean then grease everything.

 

[J_J]

I would remove the spool that is sticking and inspect and clean , then reinstall and check operation.

Use this PDF for a Prince valve. Look at page 4 for parts layout. Your valve should be similar, or search the Internet for your valve.

http://www.princehyd.com/Portals/0/products/valves/RD5000Manual.pdf

 

[wdchyd]

Sorry that didn't work, now onto the valve. On the opposite end of where the cables attach should be a "cup" for lack of a better word, it houses the detent balls for the float option on the valve. The spool moves in/out of this cup everytime the valve/spool moves. There is usuallt two Alan head cap screws holding this cup in place. It is not uncommon for this cup to hold moisture, and then the balls get rusty. You will need to remove it carefuly so as not to loose any balls/parts and clean then grease everything.

X 2....:thumbsup:

 

[elvira]

Sorry that didn't work, now onto the valve. On the opposite end of where the cables attach should be a "cup" for lack of a better word, it houses the detent balls for the float option on the valve. The spool moves in/out of this cup everytime the valve/spool moves. There is usuallt two Alan head cap screws holding this cup in place. It is not uncommon for this cup to hold moisture, and then the balls get rusty. You will need to remove it carefuly so as not to loose any balls/parts and clean then grease everything.

Thanks for that information. You are absolutely right. The boom spool cap and spool came out ok. The spool cap, springs and balls were all corroded together. I am surprised that moisture could get in. So I cleaned and polished it all and put it back together, well greased as there wasn't any at all. The spool is in good condition, not a mark on it. It now operates the way it is supposed to.
I did the same with the bucket control. It wasn't so bad as it had been maintained before, new spring. Who ever did this job didn't bother cleaning the corrosion out of it. No grease, just dry. After assembling and testing, it is ok in pulling in the bucket with the lever, and when let go, the lever comes back to neutral. When dumping the bucket, the lever does not come back. There must be something in the springs. Check tomorrow. At least I know what the problems are and, thanks to guys, how to fix them.

elvira

 

[kennyd]

Glad to hear you made progress Elvira:thumbsup: Another "trick" is to drill (1/8" or so) a drain hole in the bottom side of the cap to let moisture out. I thinks it's mostly condensation from when the valve gets warm/hot and it's cool outside. Also be sure all the linkages at the joystick are well lubed.