4300 bucket curl 'dead spot'

[defed]

is it normal for there to be a dead spot when curling the bucket on a 420 loader (4300 tractor)?

sort of hard to explain, but here goes:

when i have the forks on, and a load, the forks will drop when i move the joystick to curl up. from 'neutral' to 'active', there is a dead spot that allows to forks to drop, but moving further left, it hits 'active' and lifts. the problem is, that with a load on the forks, it is difficult to go from 'neutral' to 'lift' and miss this dead spot. if i move the lever too slowly, there is a point where the load is dropping, and if i move too fast, the load could be suddenly jerked up as i go from not moving to moving rapidly. the loader operation is sensitive, so this makes it even more difficult.

i don't know that i have noticed this w/ the bucket on, but it just may not be as noticeable since the load is less likely to want to flop down as its not out as far from the pivot point.

hope this makes sense and there is a way to fix it that i'm not seeing.

thanks.

 

[kebo]

I don't have that tractor/loader combination, but that behavior doesn't sound normal to me. It appears that hydraulic pressure is allowed to "release" from the curl hydraulic circuit as you are moving the scv lever from the neutral position to the curl up position. If it gets any worse, that is also a potentially dangerous condition, as it could cause you to unexpectedly drop a load while driving forward.

I guess you reseated all your hose connections, and inspected for any leaks around the SCV and the lines to the curl cylinders? That would be the first things to look at. If all that looks ok, I would put a pressure gauge on the line for the curl up function, and monitor the pressure as you move the lever in the curl up direction just to see what it is doing. Although, if it really needs a heavy load to show that problem, that might not give you a true indication of what is going on??

 

[kuboman]

is it normal for there to be a dead spot when curling the bucket on a 420 loader (4300 tractor)?

sort of hard to explain, but here goes:

when i have the forks on, and a load, the forks will drop when i move the joystick to curl up. from 'neutral' to 'active', there is a dead spot that allows to forks to drop, but moving further left, it hits 'active' and lifts. the problem is, that with a load on the forks, it is difficult to go from 'neutral' to 'lift' and miss this dead spot. if i move the lever too slowly, there is a point where the load is dropping, and if i move too fast, the load could be suddenly jerked up as i go from not moving to moving rapidly. the loader operation is sensitive, so this makes it even more difficult.

i don't know that i have noticed this w/ the bucket on, but it just may not be as noticeable since the load is less likely to want to flop down as its not out as far from the pivot point.

hope this makes sense and there is a way to fix it that i'm not seeing.

thanks.

How many hours on the loader? My guess is the spool that runs the bucket is worn just a little and it is releasing the pressure momentarily.

 

[beenthere]

That is not normal, at least not on my 4300 with the 430 loader and forks. That would not be good. I can move my curl up ever so slightly from neutral and it will only lift the load.

As you described it, the hoses are not switched between curl up and curl down, as movement of the joystick left is curl up.

As mentioned, maybe new o rings on the spools (if there are any as they might be a machined fit).

 

[defed]

tractor has less than 700hrs, so i would presume the loader has the same.

you say left should be curl up, i may swap them anyway just to see what happens.

i suspect that i have never noticed it w/ the bucket, pivot point is closer, so it may not be as prevalent as on the longer leverage point of the forks.

does the regen circuit have any affect on this? i can't remember where i have it set to, and i never thought to change it and see.

 

[chopped]

I was thinking the regen also. Now got me to wondering if the durl hoses are ''backwards'' that could be the problem in conjunction to the regen system. Just a guess..

 

[kennyd]

does the regen circuit have any affect on this? i can't remember where i have it set to, and i never thought to change it and see.

Not really...there are "load checks" in the valve that are supposed to keep this from happening-they keep the pressure on the port as the valve moves from neutral. It's part number 43 in the diagram. Do you have the service manual?

 

[defed]

they could be backwards, i guess. i have them color matched, but nothing to say they were ever correct and they keep getting put on 'wrong'. beenthere says left is up, and that's what i have....but anything is possible.

 

[Zebrafive]

Sounds like your lines are hooked up correct.
I would still do some swapping to see if it fixes the problem then you would know where to repair.

I would start with swapping curl with dump and if no change, curl/dump with raise/lower.

Let us know what you find.

 

[defed]

i had to move a refrigerator, so i did a quick test.

with just the forks on (heavy, about 75lbs each), the dead spot does not show itself. curls back at the lightest left hand touch.

with the fridge on (200lbs maybe?), same thing.

with my dad (180lbs) standing at the end of the forks (holding onto the fridge!)....dead spot shows up and dumps forks when touching to curl. if i continue to move further towards curl, it will regain curl.

it's gotten cold and really windy, so that's all the tests i did. i'll do more (hose swapping etc) when it warms up a bit!

thanks for the insight so far.

 

[bud4410]

i would say it is probably the regen circuit. when i put on my front blade i would get the same dead spot when i would angle the blade. changed the regen lever and the problem was cured..........bud

 

[defed]

i will try that 1st before i go changing hoses around. i actually can't remember if i have it in regen mode or not, have to check the book to see what the symbols mean...can never remember.

 

[kennyd]

Did anyone read my reply:confused2:

 

[kennyd]

i would say it is probably the regen circuit. when i put on my front blade i would get the same dead spot when i would angle the blade. changed the regen lever and the problem was cured..........bud

That is becasue the blade has two SA (single acting) cylinders, when in "regen" both lines are pressurized causing the blade to "stall".

 

[defed]

Did anyone read my reply:confused2:

of course i read it...just didn't understand why under some weight, it works fine but over a certain weight, it does not. also wasn't sure how part #43 had anything to do w/ 'load check'...i didn't want to bother you with stupid questions until i tried some other simple things 1st.

 

[kennyd]

of course i read it...just didn't understand why under some weight, it works fine but over a certain weight, it does not. also wasn't sure how part #43 had anything to do w/ 'load check'...i didn't want to bother you with stupid questions until i tried some other simple things 1st.

Part number 46... Sorry about that.

 

[defed]

Part number 46... Sorry about that.

ok, that's what i thought you must have meant, but wasn't sure. is it possible for this check valve to work fine w/ 200lbs on the frame but get 'forced through' w/ 300+ lbs?

not sure i am asking that right, hope it makes sense.

 

[kennyd]

ok, that's what i thought you must have meant, but wasn't sure. is it possible for this check valve to work fine w/ 200lbs on the frame but get 'forced through' w/ 300+ lbs?

not sure i am asking that right, hope it makes sense.

Yes-it make perfect sense, and yes-it's very possible, more weight=more pressure it need to hold.


Here is a recent thread-nothing definite was determined though: http://www.tractorbynet.com/forums/...g/187788-jd-430-loader-hydraulic-problem.html