I am having some troubles with the hoe hydraulic functions. (Case 580SE) 1st I know I need to replace some seals. I have already rebuilt the boom cylinders and have seal kits for all the others. Bucket, stabilizers, dipper and swings... All these work and not leaking real bad. But, at times it seems I can only operate 1 lever at the time with full power. Now yesterday as I was digging a hole to bury a mule that was hit by lightening and I encountered a new problem.:deadhorse The functions seemed really jerky after the fluid got warmed up. Maybe not responding properly to the control at first, then slamming to move too fast in bursts. Q: Is this probably just related to the leaky seals in the cylinders, or am I seeing a defective control valve. I have not changed the hyd fluid yet as I was waiting until I get thru with the seal replacements. If the valve has ever been worked on it was many years back before I got the machine. One more note: It seems that my stabilizer cylinders use more power than any of the other hoe functions. I can raise both together but the engine speed seems to choke as if this is a big deal. Is this common? With all the other hoe functions the engine seems to not have any problem at all with the pump load.
I'm by far no expert but the guy I just bought my Clark from said that if the hydraulics start to get jerky that it was a sign that the hydraulic fluid was getting low.
Bowen, I would be inclined to think your jerky hydraulics would be an oil delivery problem & not a valve problem. You are getting air in the oil caused by either of the following - 1) Low oil level 2) Loose clamps at suction hoses of hydraulic pump 3) Bad hydraulic pump Re the extra "load" to work the stabilizers - could be one or both glands being tight, caused by water entering the cylinders through worn wiper seals & causing rust behind the glide bearings. Or siezed pivot pins on the legs or cylinders. All the hydraulics have pressure controled by the main relief, so the engine should sound the same unless there is something like I described to demand more hyd pressure to perform it's task.
Stabilizer cylinder rods could be bent as well, not an uncommon problem.
Wow.. you guys sure do make me scratch my head and worry...:crazy All I had time to do yesterday was to check the oil level (cold) which was not even 1/2 way down to the "add" mark. I also squirted oil all over the stabilizer pins which may need to be removed to really see if they are siezed. They are not worn floppy at all, but I am not sure how tight they are. Now Willie mentions that my rods may be bent. I will need to extend them to check this, but I never noticed anything abnormal before. My pocketbook hopes you are wrong about this option. Alrman has me worried about the pump now. Another shock to my pocketbook. Remember this? Yet I see no oil leaking around the pump nor do I hear any abnormal grinding around the pump area. From all I can see the spline is still holding on OK. I would expect the thing to just totally stop pumping if this coupling slipped and stripped out all the splines. Can air get into a hydraulic system without oil leaking out? One stabilizer seal is bad enough that the thing drops to the ground if I leave it sitting for maybe 2 or 3 weeks. The other side never drops unless it is down, holding the hoe weight for a long time. Before this I was not in any hurry at all to replace the seals on this side. It is always stored in the dry so any water that might have gotten in these cylinders would be from washing the thing with a water hose. And I did this some as I was working to clean up the cylinders looking for all the leaks. The bucket cylinder has the worst leak with oil all over the latch pin.
Can air get into a hydraulic system without oil leaking out? Yes it can
:update We finally got the stabilizer cylinders off to install the seal kits and the right side was a mess. The inner rod was indeed bent with a 3/8" bow. It addition to this the tube had been damaged up close to the gland. These glands have a metal ring inside (item 5) that looks to be made into the gland. On this side the seal, the metal ring and the wear ring was all totally gone. Whoever worked on it before had apparently left all this out and it was just filled with mud. I tried installing a used gland in there but it was so bad we could not get all the new parts in with the new seals, bent rod etc. Finally gave up. Case wants $1800 for a new cylinder. Reliable Aftermarket has one for less than $700 so I will order it I suppose. (Fits both L&R side by moving plugs) I have ordered a belt tensioner from this place, but have no any experience with these cylinders. I do not know if standard Case seal kits works on them or not. One thing I have learned from this; pay attention to dirt on these cylinders if possible. Be careful with the bucket close to the cylinder and when the seal/wiper gets damaged you better fix it or rocks will damage the rod.
The new cylinder shipped fast and I installed it with no problem. It does raise better now without stressing the pump... No hyd fittings, and no grease fitting, but it did include all the bushings. I am told the aftermarket cylinder uses the same seal kits as the original one. (I had one fellow warn me that the gland threads might be slightly different to the original) For me $633 + $80 shipping was still a lot of money, but still less that half what Case wants. They also sell the seal kits aftermarket for like $20. Has anyone had ANY bad experience with aftermarket seal kits?
This is just a suggestion and the advice you are getting is all good but the mounting system on those hoes can loosen up and allow the backhoe to move causing feedback into the levers as you operate it. Just posting as a sidenote as I have seen jerkiness from that issue. I will be following this post. Mel.
This update is not about the jerky motion as I still have that slight problem. But that cylinder I bought new from reliable aftermarket is now leaking down. It's strange. Before the left one was leaking down so I decided to rebuild both when I found the right side had a bent/damaged rod. I put seals in the left one and it's fine now, but the new one I installed now leaks down. (1/2 way down in 2 weeks) At this point I do not know if the new (and cheap) one I installed is actually leaking past the seal or if I have something going on with the valve.
It would be impossible for a double acting cylinder to leak that far. The fluid is not compressible to that degree with such little load. It is the valve. Unless it is leaking externally
If it's sucking air, or even forming a vacuum inside the cylinder the rod can extend like that without the valve leaking a drop. That doesn't sound like that bad a leak to me, maybe it just needs to be used a little more to break it in? How does it hold the backhoe up? if you leave the backhoe fully raised up over night?
I have not tried that but I will. I have not used it that much, but I have not had any problem yet with it dropping during use. This started when I had the lines loose for the power steering cylinders, so I suppose some air might be still trapped someplace. I did have trouble getting all the air out of the PS cylinders. Even about the 3rd time I used it the PS would not actually move the wheels until I worked the wheel back and forth a few times. Mel was suggesting something might be loose in my valve bank which was causing the jerky motion issue. This jerking to be worse after the hydraulics are hotter. (After longer periods of serious digging)
I don't know... The left side would leak all the way to the ground before I put the new seals in. Now it stays all the way at the top.
You are right. These cylinders are upright when retracted. They are under vacuum. If the head seals aren't new they will allow air in. The aftermarket cylinders may have a different style of pressure seal which aren't designed for vacuum (don't know which ones are)
RAP sells an aftermarket seal kit that is supposed to be the same as the Case kit. Before I bought the aftermarket cylinder (it has a "Made in USA" sticker on it) I asked what seal kit it used. They told me it used the same parts as the genuine Case cylinder. I will try what Delmer suggested later and post the results. I hope it's just air in the lines someplace.
Yes some aftermarket kit dont come with the wiper seal but you can get the wiper seal from Napa for the most part. I think you just have air in the system just work the air out if the problem remains then I would look at the cyclinder then the valve because it didnt do this before the new cyclinder right?
Correct, this side has never leaked down before. This side leaking down now has the complete new cylinder. (aftermarket)
But the old cylinder had a bent rod, so it might have been held up by the jammed rod.
Good point Delmer. But after using it some more I think it was air trapped in the cylinder. I had used the stabilizers but never extended them ALL the way to the top. This tears the ground up bad the higher you raise it, so I try to be easy on the ground.
When I need to get the stabilizers all the way up for craning or a heavy pull, I usually take the weight on the hoe bucket, if I don't want to tear the ground up.