John Deere 4300 With a 430 loader.

[bigblockshorty]

I was using the bucket to push some brush to compact the pile. (bucket in the dump position) It hyper extended and now will not roll. I lowered the bucket and backed up with it on the ground to get it back from the hyper extended position. Now when I move the lever to roll the bucket, it lugs the engine down and does nothing. I pulled the cylinders off and had a hydraulic shop test them & they tested to be good. I by passed the quick connects. Still the same thing. Anyone have any ideas?

 

[J_J]

Put a hyd gage in the curl circuit and test the pressure.

 

[bigblockshorty]

I disconnected the lines @ the bucket rams & then @ the valve side of the quick connects, there is no fluid @ either one when I pull the lever in either direction.

 

[J_J]

Is the spool moving at all?

Maybe the pin has come out of the end of the lever.

Look under the boot and see if everything is connected.

 

[bigblockshorty]

Yes the spool is moving. I have the fender, seat & all the trim panels removed so I can get to it. Today I'm going to disconnect the lines right @ the valve to see if maybe the hard line is blocked.

 

[J_J]

Do you have a QD in the circuit?

Just loosen the hose at the valve and see if any fluid leaks out.

 

[bigblockshorty]

I loosened the lines from the valve, there was no fluid moving there either. I pulled the poppet valve and the spring was stuck in the valve body. I removed the spring & then the bucket rolled both directions. Everything worked fine for about an hour, now nothing on the loader works. I can get it to move about a 1/4" by pull and release the leaver.

 

[J_J]

What poppet valve?

Do you mean the load check valve. Each spool will have one.

If it is not working correctly, you will have weird hyd.

What it does is to prevent the loader from dropping when shifting and prevents the fluid from flowing back into the IN port.

Do you have a hyd gage anywhere in the hyd system?

Did you check the relief valve?

If you did, you would see when pressure is being developed.

That means that your pump flow is always flowing, and when the fluid meets a resistance like a cyl, hyd motor, or a deadhead situation.

 

[bigblockshorty]

Yes the check valve. I guess I need to find a new spring for it. No there is no gauge in the hydraulic lines. I'm trying to fix this as cheap as possible. I'm trading it in next week.

 

[jlgurr]

What poppet valve?

Do you mean the load check valve. Each spool will have one.

If it is not working correctly, you will have weird hyd.

What it does is to prevent the loader from dropping when shifting and prevents the fluid from flowing back into the IN port.

Do you have a hyd gage anywhere in the hyd system?

Did you check the relief valve?

If you did, you would see when pressure is being developed.

That means that your pump flow is always flowing, and when the fluid meets a resistance like a cyl, hyd motor, or a deadhead situation.

My dad has a 4300 with 430FEL and his will drop like wickedly fast as soon as he lets the spool go back to neutral position. We had a heckuva time loading a machine on my trailer there in July. I've been searching and reading all kinds of posts here and this is the first one that has seemed like a similar issue. Do you think it could be as simple as his check valve not working correctly? He has no major leaks, just slight weeping at some fittings. I'm trying to help him trouble shoot from a distance (MIchigan to North Carolina) because he can't afford to hire a mechanic right now. If it was a slow drop I'd suspect a damaged or worn valve but this thing drops like a rock.

 

[J_J]

The load check is a spring loaded poppet valve to prevent the load from shifting when moving the lever.

Remove the load check for each spool and check the spring and poppet seat for debris.

It also keeps cyl fluid from flowing back into the IN port.

Inexpensive to check and repair.

That suddenly drop can damage some of your hyd.

 

[jlgurr]

The load check is a spring loaded poppet valve to prevent the load from shifting when moving the lever.

Remove the load check for each spool and check the spring and poppet seat for debris.

It also keeps cyl fluid from flowing back into the IN port.

Inexpensive to check and repair.

That suddenly drop can damage some of your hyd.

Interesting... I did notice that when he pulls the lever to raise that it will drop faster for a split second before starting to raise again.

 

[J_J]

It should take about 1 min to check the lift spool load check.

The spring could have broke or there is some debris in the orifice.

 

[jlgurr]

Thank you, J_J! I'll have him check that when he gets home from his current run. I think he's only about 1/2 way through this 14 day adventure.