JD 4300 SCV rebuild???

[paulcapasso]

Hello Everyone!
So my 430 FEL has been acting weird, not holding height with or without load, and if I have a load in the bucket and pull back about 10-20 percent on the control, the loader drops. Also dumping the bucket sometimes the bucket stops then 3 seconds later it completes the cycle. The tractor has not lost lifting or curling power with the FEL. No weird noises or pulsations, everything else operates smoothly. Has this happened before to anyone? I really doubt the pistons are at fault and no air in the lines... Ideas??

 

[beenthere]

First idea, but likely not... is the bucket lines are connected to the wrong pair of couplings. It sounds like the loader is connected to the regenerative circuit.
Just an initial thought.

 

[rekees4300]

My 430 FEL had the problem not holding height with or without load and that turned out to be a leak inside one of the FEL lift pistons. But it never did the loader drop you describe so that probably isn't the problem. I'd take it to a JD dealer for diagnosis.

 

[paulcapasso]

JD Deal isn't happening..... I'm determined to fix it myself with the background in automotive repair and performance... This just started about 3 weeks ago while working at my neighbors house moving about 100 ton of trap rock. The tractor has 920 hours on it as of today, It was not beat at all I'm thinking if the lift cylinders are leaking then i wouldn't get the load lift I do. 800lbs of play sand in bags with no issue. a full ash tree in 2 / 16 foot lengths no issue..

 

[paulcapasso]

JD Deal isn't happening..... I'm determined to fix it myself with the background in automotive repair and performance... This just started about 3 weeks ago while working at my neighbors house moving about 100 ton of trap rock. The tractor has 920 hours on it as of today, It was not beat at all I'm thinking if the lift cylinders are leaking then i wouldn't get the load lift I do. 800lbs of play sand in bags with no issue. a full ash tree in 2 / 16 foot lengths no issue..

Also, only happens when fluid is warm.

 

[beenthere]

Do you have the service tech manual for the 4300?

 

[paulcapasso]

Do you have the service tech manual for the 4300?

Yes. I'm just trying to see if this is what I should be getting into first.

 

[DFB]

So what rebuild parts are available?

 

[paulcapasso]

So what rebuild parts are available?

I would assume they are since the tech manual showed the rebuild process. I'm trying to see if anyone else had the same problem and what they did to correct it.

 

[beenthere]

Does the tech manual show how to troubleshoot the problem?

 

[Egon]

Have you checked the joystick connections or lubed them??

Could there be debris in the control valve?

 

[paulcapasso]

Does the tech manual show how to troubleshoot the problem?

Unfortunately No....

 

[beenthere]

Unfortunately No....

Try the SYSTEM PRESSURE/FLOW TEST
Reason:
To ensure that hydraulic pump pressure and flow are
maintained at sufficient levels for rockshaft and SCV
attachment operation, and to determine if hydraulic
pump is worn.

It is a quote from the tech manual.

 

[beenthere]

Hello Everyone!
So my 430 FEL has been acting weird, not holding height with or without load, and if I have a load in the bucket and pull back about 10-20 percent on the control, the loader drops. Also dumping the bucket sometimes the bucket stops then 3 seconds later it completes the cycle. The tractor has not lost lifting or curling power with the FEL. No weird noises or pulsations, everything else operates smoothly. Has this happened before to anyone? I really doubt the pistons are at fault and no air in the lines... Ideas??

The problem dumping the bucket is typical error of operator due to the regenerative circuit. Causes me fits once in awhile when I dump the bucket wrong.
But don't get the loader arm drop that you mention.
Check your pump out with having the right pressures. Then maybe an adjustment by the book to the SCV relief valves.

 

[DLTTrekkers]

SOUNDS TO ME THAT YOU HAVE A LOOSE SCREW IN THAT CONTROLVALVE . .......REMOVE THE BACK-END AND CHECK .

 

[paulcapasso]

Try the SYSTEM PRESSURE/FLOW TEST
Reason:
To ensure that hydraulic pump pressure and flow are
maintained at sufficient levels for rockshaft and SCV
attachment operation, and to determine if hydraulic
pump is worn.

It is a quote from the tech manual.

I guess I better get a pressure gauge. I didn't see that In the manual but I will go look again.