Another weak front loader

[Chuck K.]

It goes pump, FEL (no relief in the fel controls), relief valve, 3pt then sump.



The relief block under the operators right foot that has the hoses connected to it has a large "bolt" going vertically up on the right side of it as you face it. Spray it off with brake clean, dry it then take that out. You will probably get the bolt, o-ring, spring and shims but not the poppet or valve seat. The shims are under the spring. You won't lose much fluid so no need for panic speed. Kubota sells them in 0.1, 0.2 and 0.4 mm thickness. every 0.1mm is 38.4 psi increase (approx).

Kubota 31351-37960 SHIM 0.2
Kubota 31351-37950 SHIM 0.4
Kubota 31351-37970 SHIM 0.1


Test the pressure before you add shims and after, then double check a week later. I like to target the high spec or just over as the spring will weaken with time. Pressure spec is 2347 to 2489psi.

Great information John... have to mark this post!!!



Thanks, Chuck.

 

[Wayne County Hose]

It goes pump, FEL (no relief in the fel controls), relief valve, 3pt then sump.



The relief block under the operators right foot that has the hoses connected to it has a large "bolt" going vertically up on the right side of it as you face it. Spray it off with brake clean, dry it then take that out. You will probably get the bolt, o-ring, spring and shims but not the poppet or valve seat. The shims are under the spring. You won't lose much fluid so no need for panic speed. Kubota sells them in 0.1, 0.2 and 0.4 mm thickness. every 0.1mm is 38.4 psi increase (approx).

Kubota 31351-37960 SHIM 0.2
Kubota 31351-37950 SHIM 0.4
Kubota 31351-37970 SHIM 0.1


Test the pressure before you add shims and after, then double check a week later. I like to target the high spec or just over as the spring will weaken with time. Pressure spec is 2347 to 2489psi.

This is a man that knows his tractor.

 

[SPYDERLK]

It goes pump, FEL (no relief in the fel controls), relief valve, 3pt then sump.

Pressure spec is 2347 to 2489psi.

That order looks as tho you could deadhead the pump with the FEL. The relief must be before the FEL controls or there will be trouble. Im guessing youre saying theres no relief on the FEL side of the valve.

I think it is a boom cyl internal leak.

larry

 

[Leejohn]

Not sure if this would do it, but check the spool in the hydraulic outlet block and make sure it is turned eather up & down or sideways I forgot the way it goes. It's in the manual.

 

[ELMO67]

Ok... this is what I have come up with so far... I wanted to build a test guage with a "T" and a pair of m/ f quick disconnects. I had a female q/d, but I needed a male q/d. My local Kubota dealer didn't have one, so I ordered one. I wasn't able to "t" in and check every line in operation, but I did connect directly to the relief block out, ( control valve in), and had 2450psi- not bad! I then connected to the lift cylinder out and had 2000 psi. Is that right, I don't think so, but I haven't found a spec for that part of the circuit yet. My loader valve, the one that came with my front plow setup, has what I believe to be some type of relief valve on the the upper left hand side of it. I removed the cap and there was a hex nut and slotted screw underneath. I backed off the lock nut, bottomed out the screw, ( three turns) and was able to raise the loaded bucket from hood height up another foot and a half. Better, but not right, and I think this tells me where the problem is. I have the information off the Husco tag, does anyone here have the ability to access the specs or application from this? leejohn, yes, the screw on the control valve is verticle, it needs to be in that position with a front mounted implement according to my manual.

 

[SPYDERLK]

Ok... this is what I have come up with so far... I wanted to build a test guage with a "T" and a pair of m/ f quick disconnects. I had a female q/d, but I needed a male q/d. My local Kubota dealer didn't have one, so I ordered one. I wasn't able to "t" in and check every line in operation, but I did connect directly to the relief block out, ( control valve in), and had 2450psi- not bad! I then connected to the lift cylinder out and had 2000 psi. Is that right, I don't think so, but I haven't found a spec for that part of the circuit yet. [[[My loader valve, the one that came with my front plow setup, has what I believe to be some type of relief valve on the the upper left hand side of it. I removed the cap and there was a hex nut and slotted screw underneath. I backed off the lock nut, bottomed out the screw, ( three turns) and was able to raise the loaded bucket from hood height up another foot and a half.]]] Better, but not right, and I think this tells me where the problem is. I have the information off the Husco tag, does anyone here have the ability to access the specs or application from this? leejohn, yes, the screw on the control valve is verticle, it needs to be in that position with a front mounted implement according to my manual.

[[[DANGER]]] --You may have disabled the relief valve. You are liable to blow your pump unless there is a relief in the line before you get to that one. Try this after setting it back. Raise your loader at low RPM until it stops, then rev it and see if it goes higher. If you have an internal leak in a cylinder there should be a marked change. Also, are you able to apply enuf down force to raise your front wheels and will they stay up when you center the stick?
larry

 

[ELMO67]

SPYDERLK- The main relief valve is before the loader control valve on this set up. I have tried raising the bucket, unloaded and loaded, at a low rpm and then raising the rpm's all the way to indicated max on the tachometer with no noticeable change in either rate of rise or total height. I can only raise the front end off the ground when the bucket cutting edge is verticle and pressing against the ground.

 

[john_bud]

That order looks as tho you could deadhead the pump with the FEL. The relief must be before the FEL controls or there will be trouble. Im guessing youre saying theres no relief on the FEL side of the valve.

larry

Dern Larry, you caught me again!

I must have looked at the diagram cockeyed. (actually, not. I "assumed" something that was wrong)

Pump, system relief, FEL, rear remotes, 3pt then back to the trans case.

Keep "proofing" my work Larry!!

jb