I'm in the process of resealing the dipper cylinder. It was leaking from the gland seal. Otherwise the cylinder worked fine. I assume that because of 2 bad areas I need to replace the piston, or maybe it doesn't affect it. If so, any recommendations where to get it from? Broken Tractor has one for about $270 delivered. I've heard of them but don't think I've ordered from them before. Had no idea that the seals/rings would be so bad. I've done several other smaller cylinders on the machine and none of them looked bad at all. Also, should I be worried about contamination from the old seals? As of now everything works fine on the machine. Should I just change the hyd. filter after running it for a while? Thanks, Doug
The real question here is - what does the inside of the cylinder look like?? That bearing looks like it has melted - has a welding repair been done to this cylinder? The gouging on the piston would indicate that there has been something metalic in there at some time earlier, as you would expect the seal to show damage as well. I think someone has maybe resealed the cylinder & reused that piston - but that doesn't explain the melted looking bearing??
If you have any gouging inside the cylinder barrel then it’s not going to matter…..reuse or new will still rip the seals apart. Feel with your fingers down inside the barrel bore. Use a flashlight also. You may need a replacement cylinder.
Or at least to have a shop full length hone.
From what I can tell, the cylinder barrel is fine. I can't see or feel any damage. Can't see any signs of any welding being done, although it's still connected to the machine so I can't see all of it. The bearing looks pretty much the same all the way around.
Could be fluid cuts but most likely a used piston installed or reused in a good tube.
Is it possible you damaged the piston when you pulled the rod out? Those indents on the outer side of the metal part of the piston look like grip marks more than rubbing/scraping. In any case, you need to smooth out the piston because it will scratch the interior of the cylinder when side forces on the rod pushes it against the wall. It should rarely happen but still. With new seals it should be fine I think. But you really need to be sure the interior of the cylinder is smooth.
Any small dents in the barrel?
Good point about the dent. This is what my piston looked like from a dent in the barrel. And then fixed up.
It was definitely awkward removing the rod, but I never directly touched the piston. I was either up on a ladder with a hammer or pulling on it with an engine hoist. When it finally did pop out, it landed on the piece of wood holding the barrel up. Not looking forward to putting it back in, or removing the piston nut. The service manual says the torque on it should be between 2400-2800 ft.lbs. From the comments from several different guys, it seems that I really need to check out the barrel more carefully. The worst area of damage on the piston would put it at the very bottom of the barrel.
Oh wow, the piston on the boom cylinder of my 680E was 1000-1200 ft-lbs according to the service manual. With 2400-2800 ft-lbs I'd think you're in the 1" drive breaker bar territory. What socket size for that bolt?
I'ts a 2-1/4" socket. I have a 1" breaker bar but haven't had any luck so far. I've tried hitting the end of the bolt with a sledgehammer to shock it. Using the sledgehammer on the breaker bar-both directions as someone suggested on the forum. Also used heat and about 10' out with pipes for leverage. Had my wife help with that. Nothing so far except that everything is bent now. I'm thinking about maybe using the mini ex to apply pressure to the breaker bar or using a floor jack. If I use the floor jack, I'm going to need to drill a couple of holes in my work bench and bolt down the end of the rod with some metal strapping to keep it in place. Also thinking about a 2500 ft. lb 1" air impact from Harbor Freight since I have several more leaking cylinders to repair.
If all the nuts are the same size why not cut yourself a wrench from some 1” plate.? That plus liberal application of an FBH (20lb minimum) should shake the nut loose. Applying the mini ex to the end of the breaker bar is only going to break something IMO, and if pieces of hardened steel start flying then you’d better be good at dodging the shrapnel.
You need a wrench cut out of 1/2" or bigger plate, then use a cheater pipe on that. heat the nut to 300F if there's a possibility of locktite. hold a big hammer on one side of the nut and smack the opposite flat with a slightly less big hammer, repeat all the way around the nut. Those seals are something I've never seen. Possibly from air burning them with the oil under compression (diesel engine compression roughly 400PSI, hydraulic cylinder compression roughly 3,000PSI !!! oxygen no good) File those burrs round, then sand so the surface is smooth and round, don't worry about the grooves and scratches, just so it doesn't gall the cylinder. Inspect that cylinder bore with a borescope, mirror and flashlight, whatever it takes to find the damage. I'd have no problem reusing that piston, assuming this isn't full time working machine. The cylinder is highly suspect.
I used to fix some case stuff back when a 580C was the new deal. The cylinder barrels were pretty light. A rock finding its way between the barrel and the stick or a light bump against something solid would dent them. Welds on the top fitting by the glad would leak sometimes from new,guys would run a pass around them and the gland would never seal. I fixed lots of them by taking a center punch to the weld and peening the leak shut . My neighbor asked my if i could weld a leaking fitting on the thumb cyl on his 200 Hitatchi ,tried the old center punch trick and hes been good for monthes now. This dosent solve your issue with that packing but gives you an idea how finicky these thin wall barrels are to impact and welding. You might have had a piece of foreign material run thru that packing if theres really no dent.
2800 ft-lbs torque at the bolt means about 280 lbs on the end of the 10' handle. Like others say here, you're in the territory of "can get hurt badly" when things slip, break, or shatter. My long wrecker bar bent quite a bit, then broke at the very end, so the end on my side sprung into my palm; hurt for days. If I were you I'd try once more with heat and about 300 to 350 lbs at the end of that 10 foot breaker bar. But I'd make sure the rod around the bolt is hot to the touch all around. The impact you consider getting most likely will do it, but you better have a lot of air flow for it. Good luck and keep us updated, hope you get it out safely with no issues.
Jonas302 in this thread HeavyEquipmentForums posted a picture of what Delmer suggested above. Joe H
The head of the bolt is recessed and there is only 3/8" sticking out. Is that enough? Also, what would I use to cut the plate with?
Shouldn't I be able to feel if there's a bump in the barrel rather than using a borescope?
Things definitely felt sketchy the last couple of attempts. I found a $200 air impact online that claims about 4000 ft.lbs and decided to order it. Much safer and it's cheaper than my 12k deductible health insurance.
Sounds to me like a really good investment for now and future.
Yes, you should be able to feel that sort of damage, if you can reach it, and it's clean. Use your fingernail also, if the piston is still on the rod, you can narrow it down to two locations depending on which way the rod was sitting in the cylinder. 3 o'clock and 9 o'clock for example. It's possible it was rebuilt like that in the past? The impact is going to need a short big hose straight to the compressor tank, no valves or quick couplers, to make the most of the power.
For what it's worth you if you don't have a bore scope you may pass on getting one for this task. The dent on my 4" diameter barrel was about 30" from the open end and indented maybe 1/8". I could see the dent inside with the naked eye if light was falling a certain way. I have a fairly new borescope with led lights on the camera head, but for the life of me it couldn't show almost anything because of the light reflections inside. I knew there must be scratches on the dent from the piston being pulled through forcefully and could barely see them with the naked eye but not with the borescope. Just my 2c
Well, you guys called it. I found the dent in the barrel. It's at the bottom. If you look at the piston you can see how far up from the bottom it is because the upper ridge on the piston is only slightly damaged whereas the bottom one is a lot worse. This also explains the strange looking damage to the seal. Probably a dumb question, but is there any way to stop the cylinder from closing completely? If it stopped about 1-3/4" up form the bottom, the seals would be above it. As a general rule, I try not to completely close the cylinder but it happens. Could something be welded to the bottom of the piston? I would like to acknowledge and thank everyone for the help, it is very much appreciated.
Oops, forgot the picture.
If it's at the very end I suppose the easiest would be to turn a piece of steel on the lathe and drop it in. As long as it doesn't interfere with the hydraulic fluid inlet at that end. Then you only lose a tiny bit of the range. The way I handled mine was to get a pipe expander set and use the largest adapters for the 4" barrel. The problem with those pipe expanders is that the adapters are of aluminum, so I cut a steel outer sleeve and used it as a wrap around. Then used the torch to heat up the dent and used many socket extensions to get the pipe expander to the dent. The barrel at the dent did not get fixed perfectly, but good enough to no longer damage the seals. I also used a whole bunch of fine sandpaper to fix the scratches made by the piston on the dent. When I put the piston back in I did my best to align the groove on the piston with the dent. I'm not saying you should do this, as I had little hope it would work, plus it was a lot of labour. You have the advantage of having the dent very near one end, so your idea of reducing the rod travel range is, me thinks, better.
After seeing the above photo, I am suspecting a Assembly damage issue, someone resealed and snagged the edge of the seal groove on the barrel edge. Displaced metal deep into groove uplifted that spot on the piston, not gouged down into it.
No issues with the fluid inlet. So, it would be OK to weld a piece of steel to the bottom of the piston? Should I weld it all the way around or use tack welds? Do I have to worry about the piston warping from the heat? I'm an OK welder, not a good welder. I'll probably be using a mig welder.
Depending on what distance we're talking about, maybe just put a few washers under the piston bolt would do it. Using a slightly longer bolt if the distance is more than maybe 1/2".
Don't weld it! why would it need to be welded? Look for stroke control spacers. See below for an example. https://www.agrisupply.com/stroke-c...923/?msclkid=745790d2f1191d38f44ef31814322ba0 If I am reading this correctly, the new seals will need to pass the dent....that aint happening without damaging them.
I'd see if there's any way to hammer out the dent, file out, sand smooth etc. before modifying the piston. Obviously it's a small dent, and it's already worn off to some degree, it doesn't have to be perfect, just smooth enough. Or look for a used or aftermarket cylinder.
You're not reading it correctly. He needs the spacer in the end of the cylinder to stop the piston before it hits the dented area. Joe H
Got it!
Interesting, this product seems to go on the rod outside the barrel basically stopping the rod going all the way in. https://www.agrisupply.com/segmented-stroke-limiter-aluminum/p/84744/ I suppose I'd be worried it gets damaged over time though.
The dipper barrel is reasonably short, can you reach the dent with your hand? If so, being down the bottom of the cyl, I would consider using a die grinder to remove the lump. Using an emery tape drum wheel will give a fairly smooth finish. (not a flapper) Bigger diameter will work best - (around 2 inch) Trouble is, you can't see what you're doing with your arm down the tube...... Goes without saying you will need to flush the cylinder after the repair job.
Cool! I think those could work. I've searched for a little while but can't find any big enough, 2.5". Biggest I could find is 2".
Id say remove the dent . Losing a bit of stroke is going to affect the the travel of the stick. Proper fix would be a re tube . But die grinding ,maybe a good honing after might do it. A creative Machinist might make a couple of guide sleeves up to fit the good part of the barrel and run a boring bar down there and remove enough to allow for a good honing.
Interesting. I can just barely reach it with the tips of my fingers now, but the length of the die grinder would help with that. Might be difficult to see what I'm doing. Do I have to worry about the wall of the barrel getting too thin? Maybe weld the indent from the outside first?
From what I could find, the cheapest aftermarket barrel was about $1100. For the complete cylinder $3300.
I wouldn't weld it, depends on the dent. I wouldn't think it would protrude into the cylinder more than 1mm or so? The barrel wall thickness is at least 5mm.
Welding the dent up outside might distort the barrel. whats the wall thickness of the barrel? The emery drum looks like a good chance to smooth a small dent . Its so close to the end that without a professional hone you wont hone much. Losing a bit of the wall down there wont be too big a problem. If it is ,your back to a machine shop type retube or a new barrel which are the proper fixes.
Yes, I just looked at it again, just need to take a little off, 2mm at the most. The only time that the piston would travel to the dent is when the cylinder is within 1.75" of being completely retracted. That will happen, but only be accident. As a habit I try not to retract it all the way. I did a "test run" to try and tell how difficult it would be to see what I'm doing. I don't think I'll be able to see hardly at all. Maybe the top of my hand above it. I was thinking that I could use some steel shim and cut a little hole in it for the bump to keep from damaging the surrounding areas too much. I'm still considering welding a 1.75" long piece of round tube to the bottom of the piston. 4.5" od and 3.5" id. One of my concerns with doing that is if it's not perfectly straight it might damage the end cap when completely retracted and cause it to leak.
Pettibone for years used castle nuts on their fork cylinders. They would weld a spacer on the castle nut tips to prevent the cylinder from collapsing all the way. It works for a while but that spacer would eventually break off and trash the entire cylinder. I would sand that hump down if I were you.
A STRAIGHT flat file, or round straight file, with the ends covered just enough that it will not file a flat surface, might file the hump out without extending past the damaged area. A chrome cylinder rod can be carefully smoothed with a flat file, as the file will ride on the chrome and cut only the hump, the inside cylinder will be softer than chrome, so even a few layers of paint might be enough to cushion the ends of the file to keep from digging in. Valve grinding paste could also be used once it's closer to the final dimension, but probably not needed, sanding would be close enough.
Spacer is a good idea if your ok with loosing the stroke I've shortened cylinders that way before but for other reasons There is no possible way your going to reach to the bottom of a dipper cylinder tube and hand machine a hump with out that you cant see with out damaging the sealing surfaces It might be best to bring it to a local small shop machinist so they can cut the tubing strait weld it on and clean it up on a lathe if desired probably cost 50 dollars
How about a shaft collar on the outside of the cylinder with relief where it would contact the wiper seal? Just clamp it on at the rod end.
Couple of these on the outside might be easiest. https://www.mcmaster.com/split-shaf...piece-shaft-collars/clamping-two-piece-shaft- collars-9/ 2" no problem. Joe H
I keep changing my mind on what I should do, but the shaft collar seems like the safest thing at this point. I need to fill a space of about 4" so maybe a shaft collar on each end and a piece of pipe in the middle. When you say "relief" I assume you are talking about rubber or something on the gland end? Maybe a piece of an old mudflap?
Probably the smart thing to do. But I'll consider it anyways. I'm out in the middle of nowhere here so very little to choose from. I tried to get someone to look at a small job a year or so ago and never got anyone to return my call. I might try again tomorrow.
Are these strong enough to stop the cylinder on their own or do they have to be up against the end of the rod?
I'd guess no, that's not what they are intended for. They do list some that are extra grip clamping, but it's only because they have a larger diameter bolt. Can't imagine anything that would be able to resist the hydraulic pressure unless it was welded on. He's saying 4" now, that's more than I had thought it would need, but still doable. Seems like that's really going to shorten the dipper movement. Might be time to get a new tube welded in. Joe H
Not rubber, rather grind the collar. You do not want to drive the collar up against the wiper seal, or it will be damaged. I would grind metal away, on the collar that will contact this seal. In other words, if you gang 4 of the collars on the rod, only the one that goes up against the wiper seal needs to be relieved so that it will not contact the seal. Here is another option: https://www.surpluscenter.com/Brand...al/2-Double-Split-Shaft-Collar-1-2768-200.axd
Can you see and feel the dent on the outside? If you can you may be able to pull that dent with the welder and a jig enough that it will be usable.
The 4" is what I need at the end of the rod to shorten the stroke by about 1.75". If I weld something to the bottom of the piston it will be 1/75".
Oh, OK, I understand now. The rod is 2.5" diameter, couldn't find any that size at the surplus center. Nice prices though. I'm thinking of using 2 collars and putting something between them to make up the distance. Might have to weld something on top of the rod because it widens out there and the collar might be forced open or break if too much force is put on it.
Interesting. Here's a picture, there are actually 2 dents.
Putting anything on the rod to restrict the length of the travel will pound the crap out of the gland. That in turn will put a lot of stress on the gland and barrel threads. A better alternative would be welding travel stops on the bucket linkage if that is possible. IMHO of course.
Since we're not done with the possible solutions I'm still thinking that shaving a millimetre off the interior dent is the best long term solution. I wonder if a cylinder ridge reamer would not be enough to shave a little there. Then just sand paper taped to a 2x4 to smooth it out. The way I smoothed mine out, and we're talking about 30 something inches far from the opening, was to tape good quality sandpaper cloth on top of a foam on the end of a 2x4. There was a lot of rubbing and my arms hurt after but in the long run you forget that.
Good to see that picture of the dent. If it were in my shop id clean those dents on the outside first, then id weld them up . I know thats a reverse on my thoughts above. Then id chuck the cylinder in the lathe ,id bet theres a center hole in the pin boss . Clean up the weld on the outside .then machine the weld out until the bottom of the cylinder can be removed . once the bottom end of the barrel is open ,set up the steady rest and dial in the bore . A careful touch with the boring bar on the dent ,then a polish with the die grinder and flap wheel . If it wont dial in right the die grinder with a stone will remove the dent then clean up with a flap wheel .Its easy to check the dents with an inside mike when the end is open like this . Plug the bottom back in and re weld . All this said you need a creative machinist . Id avoid stops on the rod that going to pound the gland and you will lose travel on the stick . An inside stop that will work on the piston will be as much work as machining the barrel of the end and you will still lose travel on the stick.
I can't see any place that I could weld something. It's the dipper, not the bucket. The dipper frame is cast iron too, I believe. Would putting something like rubber between the collar and gland make any difference?
I've gone out to the pole barn 3 or 4 times with the intent of starting to grind down the bump with a dremmel, keep talking myself out of it. But as one of the guys said, worse case if I screw something up is that I end up bringing it to a machine shop. Right now I'm thinking that I shouldn't get too excited about doing anything until I see if I can get the piston bolt removed. If I can't, then I'll have no choice but to take it somewhere and I can have them remove that and fix the barrel at the same time. I'd probably have them reseal it and put it back together too since it has to be re-torqued at 2500 or so ft. lbs.
I really wouldn't mind losing about 1.75" of travel on the dipper. I rarely extend it all the way on purpose because it pushes against a couple of the metal hydraulic pipes then. I've bent them to get them out of the way, but they always bend back. I assume some of the hoses are the wrong length. Also, if the extendahoe is over about 90% out and I extend the dipper all the way one of the hose will catch on the pin on the dipper frame. I probably only put about 200-250 hours a year on the machine and over 75% of the time I'm using the loader. That being said, I do know that the right way to do it is to bring it somewhere, I just hate bringing anything anywhere unless I absolutely have to.
This thread is getting so long I forgot which cylinder it was when I posted. A shop made new barrel may not be as expensive as you think. I doubt anyone would charge you to look at it and give you a price to repair it.
No hydraulic shop is going to fix the dents in that cylinder, they'll send it to a machine shop to cut off and weld a new cylinder to the old base, probably want a new piston also. Something like a cylinder ridge reamer would be good, especially if you can make it float like a curved plane so it only cuts the high spots, then sand and polish. If the hoses aren't working, fix them before you have steel lines to replace.
Finally got the bump ground down. Used a dremel with a flexible shaft-pencil tip(not sure what it's called). Extremely slow going since I couldn't see what I was doing. I can barely feel a little bump there now.
Had to use a machine to get the piston bolt loose. The 1" air impact didn't do it so I tried a longer pipe, about 12' long with approx. 320 lbs of weight on the end. That didn't do it so I ended up using a skid steer to apply the force. Hope I don't need to do that again. Got the cylinder rebuilt and back on the machine. Seems to work fine. I'm still trying to decide whether or not to put some collars on the end of the rod.