well this is the 4th time this repair will need to be done ***..... the machine is a 580sl with only 2k hrs, ill be loading the bucket and snap/pop..... when i raise the bucket it rolls back all the way to the stops and i can not return it unless i lower the loader. each time the shop removers the cyl and finds the treaded part of the chrome cyl has snapped off and will need repair, 1st time there was enough thread to work with, the second 2 times the chrome rod needed replacing, ouch..... after the third time they welded the stops so it would not roll back and stress the rod:beatsme that was there diagnosis .. that it was slapping back and hurting it. gotta be something else , rods aren't bent, im the only operator, i work it but dont abuse it as its my $$$$ that gets spent ointhead
If the bucket is full you must be spilling material onto the hood. The return to dig switch is either broken or out of adjustment. The loader linkage may even be bent and aggravating the problem. Those cylinder rods should take quite a beating before breaking. I have seen operators slam those stops both ways a lot and not have a rod break. I do it myself to knock stuck material out of the bucket. I wonder about the quality of the rod they are using for the replacement. I am sure the pros will offer advice about the problem.
yes... it did dump on the hood the 1st time and baffled the hell out of me, i picked up on it after that and have been able to feel it before i raise the loader high, the linkage seem to be in order and as i said it has low hours and im the only operator, im not sure about the rod quality im guessing oem case but thats a guess, both rods have been checked for bends after each failure and they are spot on. it just snaps the threaded end off on the same side... (not sure if its the same side this time but ill know in the am). ive never seen this repeat ever in almost 25 years
Check to see that the new rod they made is not shorter
The self-leveling linkage cannot be functioning if the bucket is rolling back when you run the hoist up. Actually that is an unsafe condition to be running the loader. You say the linkage seems to be in order. I don't think it can be. Here is a picture of the linkage. Check your machine and see if everything is in place. If it is all there and hooked up, you have a simple readjustment procedure to get it working. In regards to the cylinder breaking, mike is right about two different length rods on each side, Were the cylinder barrels damaged when the bolt broke off the rod end ? Maybe the bolt is too short. Another possibility is that they are over-tightening the bolt. Also if the bushing in the gland is badly worn it could be a factor. But with only 2000 hrs. on the machine that most likely isn't the problem.
If you're having your rods manufactured, make sure to use induction hardened shafting material. We manufacture rods regularly. This is not a common problem. It has to be something in the linkage or the stops.
the linkage has always been fine and working correctly until the break, then the bucket acts up and i shut the machine down , i do not run equipment that is unsafe , it goes to be repaired immediately as its owned and operated by me. when this 1st happen i though something in the linkage was screwed up and went thru it to inspect, after i found everything in order but still acting up i sent it to me case guy who found the bolt had broken, after the 2nd time we welded to build up the stops on the linkage arms thinking it might have mushroomed abit and the extension of the rod was bending and snapping the bolt. each time the rod was ck to be straight and true, which it has been, the third time we repacked the non-broken side cyl which had an existing slow weep and inspected it to be sure it was true,which it was and we replaced the broken side with a new oem case rod and bolt. this as i said is the 4th time, each time this breaks the bucket has been level in the dig position which is more or less center of the travel. (4th time ,this is getting old and $$$$)
OK, I think I understand. The self-leveling works ok until the rod breaks. That certainly makes sense. After the rod breaks the piston is moving randomly or not at all. OEM rods are being used as replacements. That narrows the problem down to something peculiar with the barrel. It is the same cylinder that is always having the problem, correct ? If it is I would be looking for a complete replacement cylinder. But, that is just my way of eliminating the problem cylinder. Are you sure that the rods in both bucket cylinders are the same length ?? It doesn't take long to pull the rod and gland out of a hydraulic cylinder. I would verify that before I replaced that cylinder.
I would be getting the dealership involved. Find out if you are the only one.
the similar length think has me thinking... as with most things some times stuff gets mixed up. my case guy is the local dealer they are a very good group and have really struggled with this , i mention this last time the length idea and he also though just maybe its the culprit. to change the entire assembly seems to be an expensive option but at this point ive spent a complete cyl or two without it repaired
That is why I suggested that option. I am guessing the dealership is charging about $400.00 to $500.00 for each repair. If the rods in both cylinders are the same length there has to be something not right with either the barrel or the gland. Did they happen to mention if the piston shows any signs of damage on either side of it ? That would indicate that it is hitting either the gland or the end of the barrel violently. Before I replaced the cylinder I would give up on the dealership and find a hydraulic cylinder repair shop that has had years of experience with these things. Have them look at it and get their advise as to what is going on with it. Plus if they repaired it with rod stock they know is good, they most likely would warranty at least one breakage occurrence. One other thing to check. When the bucket is completely rolled over into the dump position, look at the cylinder and rod. Do they appear to be stressed. What I mean by that is do they appear to be going into a bent situation ?
ctkb - sorry I'm a little confused as to what is getting damaged, please clarify if it is the piston retaining bolts breaking or the cylinder rod near the piston area? Has anyone checked the secondary relief pressures to ensure they are working properly?
alrman, it is the bolt that breaks, that said i think we got it today,, after laying out the entire linkage on both sides it seems the two plates that squeeze the cyl assembly had been installed backwards at some point,,,, this in turn was putting all the load on the side that was correct and stressing the bolt till it failed, my guess is the 1st time it broke it just broke but after that it was not correct and kept failing . so this time all that was needed is a new bolt and seals and reassembly and while its apart new bushings
Ok, that's sounds positive. I can't recall if those links are symmetrical? From what you are saying they are not. One link on the right side is different to the other 3, as it has the guide/gauge welded to the top & if they are not symmetrical, this would guide how it should be assembled. So, the left hand side is the one that has been failing? Because the links are fitted upside down - opposite/different to the right hand side? If this was the situation, wouldn't there have been a twisting happening , as the cylinders reached maximum travel? Wouldn't the two cylinders look a little 'cockeyed' when looking at the machine from the side? Sorry if I'm asking weird questions, but your problem is unusual & I want to be sure of what you have found - for future reference
the left side is correct,,,, looking at them assembled they look totally fine its the travel that's different when the pressure is applied during dig it must over stress that side that it " closer" for lack of better wording, they are very similar in design other then the one with guide link, but the bore is slightly off center and without having all of them next to another you couldn't tell. this time the bolt broke and i shut her down so no other damage. looking cockeyed at full roll back possible or full dump but i never noticed if from the seat if it even is noticeable at all.
I am curious about a couple of things that happened. How many hours were on the machine the first time the rod or bolt broke ? Prior to that first breakage were the cylinder linkages ever taken apart that you know of ? The reason I ask, is that it may be possible the problem isn't resolved yet. Is it possible the linkages were assembled correctly before the first breakage ? Then they were put together the way you have described after that first repair job. You can probably see where I am going with these questions. At some point in time someone screwed up those linkages and you have had to pay the for that mistake.
each time was with a few hundred hours the 1st breakage was the nut coming loose and breaking of the tip , there was enough thread to replace the nut and hold it down but that's when the linkage was reversed , after that it never was correct , im hopeful its right now and this will not happen again
Well ct I hope it is fixed permanently. But I see a red flag when you say the nut came loose on the rod. The correct rod in that cylinder uses a bolt to hold the piston in place. I hope you meant to say. bolt not nut.
yes bolt came loose.... time will tell, thanks for the guidance