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matt4200jd
Join Date: Jul 2003
Posts: 4 Indiana
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2002-07-22          40591

Anyone got a good idea of what normal leakdown should be for a 4200 with a 420 loader? Mine seams to go down faster than I thought it should for a 2000 machine with about 150 hrs. I got the acceptance spec from my dealer. It says that it shouldn't leak down at the cylinder rod more than 5.9 inches/hour. To me that would be a LOT. I measured mine and it went down about 1.5 inches/hour while sitting with an empty bucket. I was using it the other day for kind of a scafold with my homeade fork attachment with a pallet on it. It dropped about a foot at the forks in about 30 minutes. Can anyone give me some feed back on what their tractor is doing??? Thanks in advance!

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Art White
Join Date: Jan 2000
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2002-07-23          40596

Matt I live on both sides of the fence so to speak and I would be back at the dealer's door. The valve on the tractor is what is causing your problem and no, you are not alone as every tractor out there can have the same problem and many do just not as severe. For your drop as a dealer I would be changing it. I often have customers in with far less drop than what you have and it is not a easy problem to deal with as the new valve might be better or worse. Everyone I have changed to date has been better. ....

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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2002-07-23          40601

Guess I'm lucky. Mine is a mid-80's tractor and the loader has been on a long while. There's still very little leak-down.

The safety of using a loader for scaffolding might be thought about. However, if that's a use then any leak down probably is undesirable. If the lift cylinder hoses connect to the loader valve with quick-connects, then disconnecting the lift cylinder hoses probably would stop most of the leak-down—assuming that the valve is the major source of leak-down and that the quick-connects don’t leak.

I'm with Art, I'd probably see what the dealer will do.
....

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DRankin
Join Date: Jan 2000
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2002-07-23          40603

I have a 4100. In the winter, when the nights get below freezing and the days are just above, I can leave the bucket (unloaded) up for a couple of days with no discernable movement. In the heat of the summer it will drift down and take most of the day to do it. If there is a load in the bucket on a hot day you can actually watch it drift down. All of this assumes the engine is not running. I have not seen any drift with the engine operating. Also my 410 loader will leak down on the dump circuit if left loaded. My lift cylinders are about 18 inches long. So if the max spec is 6 inches in 30 minutes, then we are talking about six feet (!!) of bucket movement in 90 minutes as normal. ....


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matt4200jd
Join Date: Jul 2003
Posts: 4 Indiana
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2002-07-23          40617

TomG, great idea!
I think I'll disconnect the loader at the quick connects and see if it leaks down and if so, how fast. Maybe this will give me an indication on what the problem really is. Thanks! ....

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DRankin
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2002-07-23          40618

Check the web address on my post above, it has directions on how to do the test you are comtemplating. ....

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matt4200jd
Join Date: Jul 2003
Posts: 4 Indiana
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2002-07-25          40678

Well today I disconnected the lift cylinders at the quick connects and then lifted a little weight by curling the bucket. The lift cylinders didn't move at all. That tells me that the leak is in the valve. I'll contact the dealer tomorrow and see what he says about it. ....

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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2002-07-26          40684

Guess it's good to have the thing figured out even if the problem remains. You perhaps know that if the lift lines were removed with the bucket up the lines may have enough pressure in them so they won't seat easily in the female fitting when they're reconnected. Sometimes the ball in the end of the male fitting has to be depressed by wrapping a rag around the fitting to catch oil and manually depressing the ball against a hard surface. The same thing can happen if the lines were disconnected on a cool day and reconnected on a hot day.

A couple of day ago, I stepped on the return hose for my 3ph hoe while I was climbing into the seat and the quick-connect fitting quick-disconnected. The engine was running and I didn't notice the change in sound until I had operated several controls. Well, I managed to pressurize the hoe hoses very. Not only could I not reconnect the return hose, I couldn’t even disconnect the feed hose. No way the return line was going back into the female fitting. No way that ball was going to depress, and with a couple of ordinary wrenches, no way the fitting was going to loosen. I finally clamped a vice grip on the fitting, laid the vice grip handles on a footrest with the fitting ball pointed up. I placed a rag on the ball and a 2" x 6" stub across the ball and then whacked the board with a 3-lbs. hammer. Got a small squirt of oil and had to whack it about a dozen times to release enough pressure to reconnect the line. If you haven't heard of this kind of thing, it might be helpful.
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BrentB
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Posts: 21 Illinois
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2002-08-20          41442

Yesterday the boom cylinders on my 420 loader on 4200 deere started drifting after doing some heavy breakout work. I've been reading and thinking about the tests that people were trying in order to determine if it was the cylinder or the valve, and have some comments to make.

1. Disconnecting the lift cylinder quick connects and lifting the tractor up with the bucket is not a good test, assuming the leak is internal (piston seals). The reason is that the volume of oil on the cap end is larger than that on the rod end. Let's say that the sum of the oil on both sides equals 200 cubic inches. There is one and only one cylinder stroke that contains this amount of oil. If the rod is retracted inwards one inch, then oil equal to 1 inch of the rod volume must be subtracted from the sum of the oil. Since there is no oil added or lost to the cylinder and lines, the cylinder is locked. This ignores the slight oil compressiblilty. I believe that the cylinder could be extended because a vacuum can be created (cavitation).

2. I switched the bucket tilt and loader lift quick connects at the valve and checked for drift. This should work because each valve section is independent. It is unlikely that both are leaking!

3. I like Deeres suggestion of unhooking the cylinder, but it would be smarter to either pull the rod end pins, or perhaps take off the bucket, and power the lift arms down ove an embankment. I don't like thinking about the loader up in the air while removing hoses.

4. I find it annoying that these cylinder are leaking in the first place. I bet I don't have 10 hours of loader time on the tractor in 2 years. I looked at the schematic and there are no line reliefs, so I wonder if I overpressured the cylinder via the bucket cylinder, or pushing against the pile.

Thanks for listening to me rant and rave.
Regards,
Brent ....

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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2002-08-21          41460

Brent: I'm always trying to learn something. I thought that leaving the bucket up with a load in it and disconnecting the quick connects would be a decent test for oil leaking past the piston seals. I figured the only place for oil to go is either from one side of the cylinder to the other or out around fittings where it could be seen. Cavitation would be an issue, but it occurs mostly when dumping a heavy load with loaders that lack a fast-dump feature.

As noted, leaving buckets up even without loads is a safety issue and shouldn't be done without precautions. I'd never try to loosen fittings on a cylinder hose with the bucket raised. The bucket could drop like a rock. At minimum, oil on the lift-side lines is going to be under high-pressure. The fittings probably wouldn't loosen easily but might give a squirt of high-pressure oil if they did.

It's possible there are no pressure-relief valves, but my impression is that many valve assemblies contain pressure-relief valves to guard against load shocks when the control valve is closed. I'm not certain, but I think these relief valves dump into the low-pressure return galley on power-beyond valve assemblies. Typically valves for load shocks are set for over 3,000 lbs. while most system relief valves are just over 2,000 lbs.

I think that many valve assemblies also contain relief valves in their inlet sections for setting a system relief pressure or setting a lower pressure for one piece of equipment. These valves also can be used on PTO pump equipment that may not have a system relief valve similar to a tractor's pump. I think most inlet sections also have a check valve.

I'm assuming that the tractor's loader valve is a power-beyond type or was otherwise properly plumbed. Power-beyond prevents damage to a valve assembly if a downstream device such as a 3ph and loader are operated simultaneously. Other than that, I'd expect that the loader is sort of designed to protect itself but maybe somebody who doesn't have to rely so much on impressions will respond.
....

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BrentB
Join Date: Jul 2003
Posts: 21 Illinois
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2002-08-21          41487

Tom,
I couldn't decide if you believed me or not that disconnecting the quick connects would not detect a piston leak! :)

Anyway, tonight I took off the bucket, hung the loader arms
over a shallow ditch so I could bottom out the cylinders with the arms all the way down. I then unhooked the cap end hose and pressurized the rod end of the cylinders. Oil came gushing out of the unhooked hose, which told me that cylinder was the culprit. I guess I'll learn how to change seals in a cylinder this weekend. I think seal kit is about $20, but $80 if dealer does it.

I'm also seeing corrosion from the battery on the oil cooler again. They replaced it once due to no vent tube on the battery.

Regards,
Brent ....

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Art White
Join Date: Jan 2000
Posts: 6898 Waterville New York
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2002-08-22          41504

Brent unhooking the hoses from the cylinder on the non-load end is how we test our cylinders to see if they are good. It is a little messy but it is the only way we have found to check the cylinder against the valve. While apart check for cylinder scoreing. On some units we have even seen where when loaders are painted that paint chips off the cylinder rod was actually the culprit holding the seal away from the cylinder. ....

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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2002-08-22          41507

Brent: I figure that I always have something to learn, and I might learn it if I just listen. The fastest way to never hear anything is to say 'I've got the answer' so I seldom say that.

I think a pressure test described by you and Art is better way to see if a cylinder will hold up to relief pressures. I guess my attitude is that if a bucket is virtually leaking down as you watch it then there definitely is a leak. Disconnecting the quick-connects is going to remove the valve as a candidate for the leak. If it still leaks down then it's almost certainly the cylinders, but I guess it's not so obvious if the leak-down stopped. Then a pressure test would likely sort it out. However, I am always open to learning something here too.

I seem to recall stories that removing the shaft/piston from the cylinder can be difficult sometimes. I'm not sure if it's just certain makes of cylinders but it might be good to find out if there are any tricks that are helpful.
....

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Ted@Abbeywoods, LLC
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2002-08-22          41523

I'm sorry I don't have a quick remedy for this problem, instead I'll offer an observation based on over forty years experience. All of the small tractors (non-commercial grade) used by the landscapers I know and work with have this problem to some extent. I use my two machines professionally and both have some loader cylinder leak-down (bucket and lift), the question is when to do something about it. Neither I, nor my associates, get worked up over the matter until the machine can no longer hold its load during normal operation (80% throttle at normal operating temp). I have found that it can be a costly wild goose chase to try and have perfection, and only when it becomes a clear cut safety issue do I pull a machine off the job. When I do, it goes to the dealer or a specialist. I do this because armchair hydraulic troubleshooting can be fatal even for one with good mechanical skills. So be forewarned, peace of mind can get expensive if there is no clear cut reason for the problem. And for God's sake, if you don't know the territory, find someone who does. Good luck. ....

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BrentB
Join Date: Jul 2003
Posts: 21 Illinois
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2002-08-22          41528

I ordered the seal rebuild kit... it was only $11.00!
I'll be sure to check for scoring and paint chips when I open up the cylinder. I assume the head end just unscrews, but will check with the dealer.

As far as leakage, I noted that the bucket cutting edge would drop about 8 inches in the first 6 seconds, but then would slowly drift at the rate of 23 inches in 12 minutes.

My wife is sure getting tired of oily clothes every night after I mess around with it!

Brent ....

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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2002-08-23          41542

I probably want to correct that much leak-down myself. The quick 8" of drop would give me problems when using the loader for moving loads by chain on and off my utility trailer. I probably could tolerate the leak-down for just moving gravel around.

If there are difficulties in fixing the cylinder, most areas have general hydraulics shops that often can rebuild seriously damaged cylinders. If it comes to it, comparing prices between a new of a rebuilt cylinder might be worthwhile. ....

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BrentB
Join Date: Jul 2003
Posts: 21 Illinois
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2002-08-23          41559

well, I'm giving up. The cylinder has some sort of bizarre snap ring that you have to reach through a little hole to remove. I put a pipe wrench on the head end and couldn't even budge it.

The dealer said he would do it while I wait (20 miles away), so I'll take him up on the offer.

BTW, the battery they gave me in Feb went bad, so they gave me a new one. Did anyone else have the oil cooler corrosion problem from battery gases? ....

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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2002-08-24          41570

Brent: I think there's a lot of discussion in the archives about the battery problem. I think that at least one person had a rad tube corrode through. I seem to remember that there may be a JD factory fix for the problem. Batteries with other type of venting, or non-maintenance types also were mentioned.

Too bad you seem to have stumbled on one of the cylinder repair problem stories I heard. Not too bad a problem though. I wish my dealer was 20 miles rather than almost 200 miles away. ‘Do it while I wait’ is a problem for me.

I don’t know how old the loader is, but 10-hours in 2 years and blown cylinders is cause for ranting. Back to my ranting. I’m pretty sure that most valve assemblies have relief valves to protect against load shocks. If true, the cylinders really couldn’t be ‘over-pressured’ and it’s unlikely that ‘hard use’ caused the problem.
....

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WallyB
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Posts: 7 Abbot Maine
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2002-09-14          42364

FWIW: I just purchased a 4110 with 410 FEL. While spec-ing it, I happened to ask about "locking" the loader in the raised position... the JD guy basically replied that JD is perhaps too obsessed with safety, you can't. It's designed to leak down. He did say "off the record" that some guys cut and clamp a piece of angle iron to use as a lock. ....

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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2002-09-14          42367

Now that's an interesting comment. There have been some comments from people who thought their loaders leaked down excessively, but I can't remember remember which tractors were discussed.

If the JD guy is right, I guess I can understand the idea aggravating as it might be. The usual safety thing mentioned leaving buckets up is the chance that they might drop on somebody. I tend to sit everything down even if I'm going to be away from the tractor for a short while. However, there's been more than a few times when I've left the bucket up that I've almost ran my head into the thing when walking around the front of the tractor. It's probably good that there's nothing that encourages me to leave the bucket up.

I hope the design mentioned is something other than just sloppy tolerances, which would be sort of like buying new antiques.

....

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Peters
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2002-09-14          42368

The main problem is that someone will operate the controls and drop them on another person. Stubbing toes or bashing heads is secondary.
With two children mine is always on the ground when stopped. ....

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MRETHICS
Join Date: Jul 2003
Posts: 190 Star City, Indiana
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2002-09-14          42370

Loader leakdown can be caused by lot's of things already mentioned here.

I know that 10 hrs on a loader that is leaking is a heartbreak.

Paintchips have been a culprit here in this store as well. In most cases, it has been a combination of problems.

The amount of oil that leaks past a seal and causes the load to drop is a very small amount. Leaks like that can sometimes be hard to find. I have even seen loader leakdown problems that only would happen when it was warm outside. And In jan. there is no problem.

As far as the snap rings on J D cylinders, snap ring pliers will get them out easy enough. They are not a special tool, but are different than anything you will see at sears. Snap-on has them.

....

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Bob in Mich.
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2002-09-30          43139

I purchased a used JD 4400 with the 430 loader. It is 2 years old and am having the same type of problem with the bucket drifting down on it own whether the tractor is on or it is running. The bucket can be completely empty and it just falls. I have used the lock on the bucket and the bucket only still falls. Any ideas?? If I were to take it in to a dealer what do you think they charge for looking into this.
Thanks for your help and I enjoy reading everyones comments and past experiences. ....

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BrentB
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Posts: 21 Illinois
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2002-09-30          43142

It cost me $50 labor and $11 for the seal kit to rebuild one lift cylinder on the 420 loader. I'd suggest:
1. swapping the lift and tilt hoses at the quick connects first. If the leakage problem switches from tilt to lift then you have a valve spool problem. If not then you have
a leak in one of the pair of cylinders.

2. There are instructions posted here on how to determine
which cylinder is leaking.

Good luck.

Brent ....

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Bob in Mich
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2002-10-01          43182

Thank you Brent for the info. I will let you know what I find. ....

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Bob in Mich
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2002-10-16          43898

Brent, I read how you took the cylinders into your dealer to remove the bizarre snap rings. I am running into the same problem. Did you see how they removed them. I saw on the post MRETHICS said something about snap ring pliers. Is there anything else that I might use to do this. I would really like to try to save money and do this myself because if this doesn't fix the problem, I may ending up buying new cylinders. Thanks for your help. Bob
....

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