JD 4300 weak front end loader

[arkvet]

2002 4300 HST with 430 FEL. Recently started having issues with FEL being weak. 3 pt still seemed to work normal. PTO and HST drive seemed to have normal power. Issue seemed to be confined to FEL. Since it was due I went ahead and did a hydraulic fluid change and cleaned screens and filter. Issue still present.

With no weight in the bucket the FEL performs normal and you wouldn't think there was an issue. Put 500 lbs in the bucket and it acts like I put 3000 lbs in it. With a heavy weight in the bucket it will left very slowly but you can hear the strain. Throttle at highest RPM will aid in the lift. Any reduction in the rpm will significantly reduce the ability to lift a medium to heavy load in the bucket.

Where do I start on this trouble shoot?

Also, FWIW my power steering is really stiff and hard to turn when not moving. I've had this issue for a while and am pretty sure this is related to the power steering pump... but the tractor is still very usable as it is so I haven't taken the time to trouble shoot this yet.

 

[Industrial Toys]

If there is no fluid leaking to the ground, there really are only two options. Worn Spool valve or worn cylinder seals.

 

[arkvet]

It's an older tractor so it certainly leaks a little fluid here and there but nothing more than normal. I'm not adding hydraulic fluid every couple hours by any means.

I will look into this "Spool Valve" that you mention.

Thanks

 

[Industrial Toys]

I don't even know how you narrow it down between cylinder or spool.

 

[arkvet]

When you speak of "cylinder" are you referring to the lift and curl cylinders? Sorry if that's a dumb question.

When I look up the Spool Valve I find the actual spool valve and also a pressure relief valve. Are the parts of this system that could be dirty / contaminated / need adjustment or if I am pretty certain this is the issue do I simply buy a replacement(s)?

Again, sorry if those are dumb questions. I used to have a local retired guy that worked on my tractor but he recently retired again, so mainly drinks coffee and goes fishing. Now it's kinda back on me. lol

 

[Industrial Toys]

YEs the cylinder is the loader and bucket ones. Is there a relief on the spool? Maybe it's weak. That would be an easy fix.

Our 6200 has never lifted what I think it's capable of. I always felt that JD is conservative in their relief settings. That's OK. You just end up breaking stuff.

 

[arkvet]

I had a lift cylinder break a few years back and rather than replace with an overpriced JD cylinder I fabricated my own out of a pair of slightly larger bore cylinders and they work so much better than the originals. Slightly slower lift than the OEMs but much smoother and stronger / stable. I know this is NOT the issue. The cylinders seem to be working fine. I will say that while trying to lift heavy loads with high RPM when the FEL is really struggling the real "grunt work" seems to be occurring at the base of the FEL joystick / control. That's where I can hear and kinda feel the strain. Not sure if that info helps?

 

[arkvet]

YEs the cylinder is the loader and bucket ones. Is there a relief on the spool? Maybe it's weak. That would be an easy fix.

Sounds like I need to really examine the maintenance manual on this section. Used Spool valves seem to be in the $150 range so not a major expense if that's what it may take.

 

[Industrial Toys]

How many hours? A lot of loader work?

 

[arkvet]

Not sure on hours as the tach / gauge panel died several years ago. I'd estimate easily 1500 hours but probably closer to 2000.

LOTS of loader work. I carry round bales of hay with frequency. Before the home built lift cylinders were installed this seemed like a tough task for the loader. After the new cylinders it (used to) carry round bales with ease.

I will say that the reduced FEL lift capacity was not a subtle and slow change. It went from tough as a mule to super weak in very short order.

 

[RNeumann]

I would start with the easy one- check all the QDs between the loader and valve.

 

[arkvet]

I would start with the easy one- check all the QDs between the loader and valve.

The FEL is never removed. What would I be looking for at the QD's?

 

[Industrial Toys]

That would mean a lot of oil on the gorund. NOT the case here.

 

[RNeumann]

The FEL is never removed. What would I be looking for at the QD's?

The QDs are a choke point for the fluid. Any little debris can get hung up in them. I’d try switching the curl and lift to see if it changes performance. Long shot? Yes! But it’s an easy check. Plus it would be part of a good systematic approach.

A second easy check, if the loader joystick is cable actuated, would be to check cable function and adjustment.

Your next step, IMHO, would be to remove hoses and cap/plug them on the lift or curl (whichever is weak) cylinder. I would do one at a time and see what happens. A bad seal in one of the cylinders will be noticeable with this test. Based on your description this is my guess...

A bad cylinder seal is more likely than the valve.

 

[arkvet]

The QDs are a choke point for the fluid. Any little debris can get hung up in them. I壇 try switching the curl and lift to see if it changes performance. Long shot? Yes! But it痴 an easy check. Plus it would be part of a good systematic approach.

A second easy check, if the loader joystick is cable actuated, would be to check cable function and adjustment.

Your next step, IMHO, would be to remove hoses and cap/plug them on the lift or curl (whichever is weak) cylinder. I would do one at a time and see what happens. A bad seal in one of the cylinders will be noticeable with this test. Based on your description this is my guess...

A bad cylinder seal is more likely than the valve.

Thanks! Those do seem like easy checks and it makes sense to swap the lift / curl attachments. Let's hope it's some debris in the lines which is much simpler fix than a lift cylinder with a blown seal. I honestly am not sure if the curl cylinders are weak as well. The testing I did didn't really involve a weighted curl of the bucket. However, I will say that through the struggle to keep the lift cylinders extended I don't recall the curl cylinders trying to leak down and dump the load.

Sounds like some simple testing is in order.

 

[Industrial Toys]

But the cylinders are newer. I would maybe try and swap out the quick disconnects, bucket for main cylinders if possible. That could tell you if the spool has an issue provided your bucket circuit spool might also be worn.

 

[RNeumann]

As you can see from the video, if you have a bad seal it can play heck. They use QDs as “caps”. Obviously caps are a cheaper option.

Bypass testing a hydraulic cylinder - YouTube

 

[Leejohn]

After you do the above checks pull the relief valve seems to be stuck open a little to me.

 

[arkvet]

Thanks so much for all the suggestions. I haven't yet had time to trouble shoot the issue but I have lots of good direction and it's much appreciated. I did have a brief moment to jump on the tractor yesterday to better assess the specific behavior. Here is something I noticed that *might* help to point towards the culprit. Hopefully I can explain it ok.

After startup (no weight on the bucket) The tractor will lift the FEL pretty normally but when the stick is released it will fall a little and then "settle in" and not leak down very much at all. At a high RPM the Loader will almost hold steady with no leak at all. With the slightest pull back on the loader control (to lift) the bucket will fall pretty quick, but when released back to the neutral position it will hold pretty well again. High RPM and full pull back of control will lift the bucket even with a medium load, but it will only hold that load if the control is back to the neutral position. The absolute worst position for the control to be in (to hold a load) is just a slight pull back. Neutral holds the load. Slight pull the load falls. Full pull back and the loader struggles to lift but will lift a few hundred lbs.

I don't know the system extremely well but my gut says if a cylinder seal was blown that it wouldn't want to hold in the lifted position at all without constant pressure being applied (stick in back position). This behavior sounds more like a pressure relief valve?

thoughts?

 

[Leejohn]

Sounds like you also have a bad load check in the boom system.