John Deere 4300 With 430 Loader , loader very slow and non responsive

[Joeblack101]

So I've read a few post on here discussing some of the same problems I've been having , however , mine seems to be a little more difficult . Loader stopped working completely several months ago . Had to pull the lever down and to the left hard to get it to move at all . I flushed the system hydraulics and cleaned the suction screen and replaced the filter . Oil level was a little low and not in the site gauge . After flush loader did start to work a little better as up and down works off lever right but it's very slow . Have to rev up to full throttle to get anything out of it . I do hear it going over relief for loader up and down , and bucket tilt down . Here's the kicker , bucket tilt in works perfect and low idle and full and won't go over relief until the pressure dead heads and it goes over relief at end of the stroke which seems normal . It's the only function that works correctly and I can physically see the lines ' jumping ' when that function is activated at the quick disconnects . So I took out relief valve which is adjustable and found the o ring ok but backing plate to o ring blown . So I ordered kit and replaced and still no difference . I replaced both male and female couplers for loader up and down and made no difference . The relief adjustment seemed very easy to adjust so I replaced the whole relief valve . No diffference . . I know the rubber boot in both pumps doesn't look like it's leaking , I have perfect power steering and 3 point hitch operation . But just screwy loader . Up , down and bucket out are slow as crap .will only move at full throttle but veryyyyy slow. Only one that looks normal is Bucket in . I have not got to put a pressure gauge in the system yet , but I'm assuming since the 3 point works ok and bucket in seems fine that the pumps good . I seen most people solved this by relief blockage but that's not my case . Any help is greatly appreciated . Thanks a bunch .

 

[oldnslo]

Joe,
With the engine off can you check the control valve spool travel on both the raise / lower and curl / dump functions. The spool travel from the spring loaded center condition should be very similar for all of the loader movements. I.e. has something in the linkage come loose?

When you state you can hear the pump going over relief during raise lower. Is this all the time you are trying to move the loader?

 

[Tx Jim]

Welcome to TBN
How old is loader? I'm wondering if one or more boom cylinder piston seals are faulty? With boom totally raised up remove boom cylinders rod end hoses then with engine running move control lever to raise position to determine if oil exits open rod end hose ports.

 

[Joeblack101]

Thanks for the replys . Loader and tractor I believe are from 1999 or 2000. It may just be my eyes , but there's 3 valves in the loader valve that the joystick is operating . The first one closest to the right fender is loader up and down . And the next one is bucket tilt in and out . It looks like the bucket in and out has more travel in it then when I'm using loader up and down . Linkage looks ok but I put a pry bar in a gently pushed the valve to try to get it to move a little further for loader up and down and it don't move any further then what the lever is taking it . The Bucket in does not go over relief until it fully tilts in , then goes over relief . This is the only function I can use that I don't hear it going over relief . It's constinatly " hissing " with loader up and down and bucket out . Like it's going over relief at all types of throttle except for low throttle . I get nothing other then bucket in at low throttle. It has to be full throttle to get anything else to move . And I hear the hiss of the relief and can feel the tube getting hot that it's relieving the pressure back through . Hope this makes sense

 

[oldnslo]

Joe,
From what you are describing it does sound like there is a restriction some where in your system. The hard part is determining where this restriction is. Since everything is hard plumbed from the valve to the quick disconnects you can only watch the hoses going to the loader. When trying to raise do you see the hoses stiffen or swell like they are under pressure?

Have you tried swapping the hoses from lift / lower to the curl / dump function? I am not sure if you have the regenerative dump feature on this model but it should still raise while operating the curl feature.

Not sure you kept the old quick disconnects but could you make up a jumper hose to remove the lift lower cylinders from the circuit? I.e. just connect a hose across these ports. This would isolate the Loader from the valve and point us in direction of the potential fault area.

If you could get a pressure installed in the pressure line would also be helpful. Not sure if JD put a test point in this circuit or not.

 

[Joeblack101]

Joe,
From what you are describing it does sound like there is a restriction some where in your system. The hard part is determining where this restriction is. Since everything is hard plumbed from the valve to the quick disconnects you can only watch the hoses going to the loader. When trying to raise do you see the hoses stiffen or swell like they are under pressure?

Have you tried swapping the hoses from lift / lower to the curl / dump function? I am not sure if you have the regenerative dump feature on this model but it should still raise while operating the curl feature.

Not sure you kept the old quick disconnects but could you make up a jumper hose to remove the lift lower cylinders from the circuit? I.e. just connect a hose across these ports. This would isolate the Loader from the valve and point us in direction of the potential fault area.

If you could get a pressure installed in the pressure line would also be helpful. Not sure if JD put a test point in this circuit or not.

Yes I can see the line physically jump when the loader bucket in is actuated . It's so much pressure that I can't even turn the hose in the disconnect. After swapping the quick connects I can now ' feel'' some pressure in the loader up and down hoses , but nothing like the bucket in pressure hose has . I can still turn the hoses in the disconnects when it's actuated . Nothing like bucket in . I made a quick connect fitting to test the pressures in each here this evening . I think that will tell if it's a pressure problem from the pump or in the loader valve assembly . But I did try swapping loader up and down with the tilt in and out ... however I think I had the return hose routed wrong in the disconnects bc it instantly jumped the loader up but stopped fast and bogged the tractor . I realized I had it connected wrong so I put it back to normal and went from there . I will test pressures this evening and come back from there .

 

[dfkrug]

Welcome to TBN
I'm wondering if one or more boom cylinder piston seals are faulty?

That is what I suspect, too.

I have been able to hear the oil flowing past a bad piston seal when trying to raise
the FEL. Also, a heat gun will show a significant temp diff between each side. If
one seal is slightly more worn than the other, it will bypass first, and the oil flow
then degrades the seal quickly.

 

[oldnslo]

That is what I suspect, too.

I have been able to hear the oil flowing past a bad piston seal when trying to raise
the FEL. Also, a heat gun will show a significant temp diff between each side. If
one seal is slightly more worn than the other, it will bypass first, and the oil flow
then degrades the seal quickly.

Bad seals should not have any adverse effect on lowering the loader only on achieving down force like trying to raise the front end off the ground. Agree bad seals would slow down the raise function.

 

[oldnslo]

Yes I can see the line physically jump when the loader bucket in is actuated . It's so much pressure that I can't even turn the hose in the disconnect. After swapping the quick connects I can now ' feel'' some pressure in the loader up and down hoses , but nothing like the bucket in pressure hose has . I can still turn the hoses in the disconnects when it's actuated . Nothing like bucket in . I made a quick connect fitting to test the pressures in each here this evening . I think that will tell if it's a pressure problem from the pump or in the loader valve assembly . But I did try swapping loader up and down with the tilt in and out ... however I think I had the return hose routed wrong in the disconnects bc it instantly jumped the loader up but stopped fast and bogged the tractor . I realized I had it connected wrong so I put it back to normal and went from there . I will test pressures this evening and come back from there .

Since you get full pressure in one direction on your curl I doubt that this is a pump problem.

 

[Spanner]

So I've read a few post on here discussing some of the same problems I've been having , however , mine seems to be a little more difficult . Loader stopped working completely several months ago . Had to pull the lever down and to the left hard to get it to move at all . I flushed the system hydraulics and cleaned the suction screen and replaced the filter . Oil level was a little low and not in the site gauge . After flush loader did start to work a little better as up and down works off lever right but it's very slow . Have to rev up to full throttle to get anything out of it . I do hear it going over relief for loader up and down , and bucket tilt down . Here's the kicker , bucket tilt in works perfect and low idle and full and won't go over relief until the pressure dead heads and it goes over relief at end of the stroke which seems normal . It's the only function that works correctly and I can physically see the lines ' jumping ' when that function is activated at the quick disconnects . So I took out relief valve which is adjustable and found the o ring ok but backing plate to o ring blown . So I ordered kit and replaced and still no difference . I replaced both male and female couplers for loader up and down and made no difference . The relief adjustment seemed very easy to adjust so I replaced the whole relief valve . No diffference . . I know the rubber boot in both pumps doesn't look like it's leaking , I have perfect power steering and 3 point hitch operation . But just screwy loader . Up , down and bucket out are slow as crap .will only move at full throttle but veryyyyy slow. Only one that looks normal is Bucket in . I have not got to put a pressure gauge in the system yet , but I'm assuming since the 3 point works ok and bucket in seems fine that the pumps good . I seen most people solved this by relief blockage but that's not my case . Any help is greatly appreciated . Thanks a bunch .

What do you mean by you "flushed the system hydraulics"?

What was the condition of the suction screen? What sort of debris, if any, were found??

A lot of disconnecting and replacing has been going on here so it's pretty hard to pinpoint your problem.

The "backing plate to O-ring was blown" so did you retrieve all the pieces?

Loader finally "stopped working completely several months ago". How long had you noticed it getting slower?

And I read that you clearly never check your fluid level in the trans. It's not surprising that you have an issue now.

Check for obstructions in the Quick Connetors. Oil has to travel through smaller passages here. Swap the couplings for Raise/lower and Curl/uncurl to see if the problem is hose-related or valve-related.