I lost the seals in the 580C extendahoe ram, so took it all apart, pulled out ram from cylinder, put new seals on it, but now it won't slide it back in the cylinder. It came out hard too, unlike the bucket cylinder, which also was leaking so I rebuilt that too. Here's a picture of the cylinder, all gooped up with grease to hopefully help. There looks to be sort of a "ledge" at the end of the threads that kind of catches on the endmost seal piece, is there something I can do to make it slide in without damaging the seal? I'm imagining some kind of tool/process like sticking a piston in a cylinder on a car where you have that clamp thing that holds the rings in tight? Or maybe taking a little Dremel tool and sanding/grinding a radius on the ledge at the back end of the threads? What should I be doing here?
did you compress the piston seals?
I just tightened the big bolt in the end like I did on the other six cylinders I've rebuilt so far on this backhoe, but this one's really tight. Is there I tool I should get to compress them?
Yes. I use a piston ring compressor.
But how would you get the seal to stay compressed around 4 inches down the cylinder from the end still? The one I used when I rebuilt my jeep clamped about an inch from the end, do they make "longer" ones?
I just tighten the ring compressor down against piston as much as I can. Let it sit for a little bit. Remove ring compressor and then put everything together. I put the seal on the piston and do this while I’m installing seals on the gland. If you have a local hydraulic shop they use a hydraulic tool to compress piston seals. You might could take piston off of ram and get them to do it for you.
Hey, that's a good idea, I'll see if I can find my motor ring compressor and just clamp it down for a half hour then give it a shot
I are you sure grooves in piston were clean
Is this an optical illusion or some kind of a lip
Piston seals can be installed backwards. Is it possible that is what happened ? Do you have the piston located perfectly centered in the bore ? I once had bi***h of a time like you are having. I cut a section out of a plastic milk carton and laid it on the bottom half of the barrel threads. It worked like a charm ! A heat gun pointed inside the barrel, on high for 20 minutes may help to.
Yeah, that's a lip, it's where the threads end and the beginning of the smooth section where the seals normally slide back and forth in the main part of the cylinder. The ram slides in a bit, but then kind of binds on what looks to be about halfway through the first seal. It doesn't rip it or anything, just kind of jams, so that it seems if it was slightly compressed it would just slide right in. I can't really see any pitting or rust of anything on that ledge, but it's just a tight fit. It's kind of hard to get a super straight shot since the cylinder is still in the end of the extendahoe box tubing, and I have a 3 foot piece of steel holding the end of the boom up off the ground so I could pull the ram out. That means the whole thing is kind of angling down.
Guess Case does it different, all the other cylinders I've done doesn't have a lip, they have all had a smooth bevel going smaller as it goes in. The lip when expanded looks like part of a old seal (2 edges)
You would think they'd have a bevel, but this one seems not to. I know the end of the ram shaft has a bevel so you can slide the seals over it, so they're aware of the bevel concept
I'm w/ you AllDodge.. looks just like the leftovers from the old seal.. Just for kicks, if the ring compressor doesnt work, see if u can cut it w/ a razor blade.. Every one I've ever worked on {not many} had a bevel..
I use electrical tape stretched as tight around the piston seals as I can get it. Leave it on for a bit then remove it right before installation.
I have gobs of grease in there, but there's nothing else but just that ledge with the threads closer to the end. Wish there was a bevel, that'd be nice.
& I've always used & all my more experienced cylinder rebuilders use veggie oil for cyl. ram install.. Dont know if it'll help or not.. Good luck.
Might be an aftermarket cylinder. ????? I have never seen a Case barrel with a 90° ledge in it. Did you carefully compare the old seals to the new seals before the piston was reassembled ? Are the seals installed in the correct direction ?? If you are getting the piston to go part way into the barrel and then it binds up something is wrong. It is very important to have the rod and barrel perfectly parallel to each other or I guarantee the piston will be in bind and not move forward. I never use grease. Just wet the piston with a lot of hyd. oil.
I don't think anyone's been into this cylinder, it's the 7th one on this machine to fail recently with rotted seals, so I'm guessing they're all the same age. All the rest slid in relatively smoothly, just this one is snug. Getting it out of the cylinder wasn't super easy either, had to put a pin in the end of the shaft where it normally attaches to the stick and beat on the pin a little bit, it's like it hung on the very end. The threads came unscrewed fine, and I don't see any other damage. I wonder if there was a little rust in there over the years that made it rough? Not sure. Will wipe the grease out and get some hydraulic fluid. I'll check the seals again, pretty sure they're right. I stopped trying to force it in before I took the chance of damaging them, so they still look fine to me, not ripped or something.
Take a pic of that barrel I d with it clean. Something don’t look right to me.
The lift rams on my JCB had a sharp 90 degree ledge where it transitioned from the bore to the threads. So sharp that if I slid my thumb along it with pressure, I probably could have drew blood. I had to take emery cloth and smooth off the ledge before I could get the piston back in. I don’t know how the factory got them in without destroying the seals.
Usually on that type of lip there is an insert in the seal kit that is an installation guide.
I looked at the cylinder in the parts book. The cylinder is simply a plain ole Case cylinder. I am still wondering if the piston rings (seals) are stacked correctly and in the correct direction. It is crucial that the soft seal is in the proper location and not backwards on the piston. There is no reference to a seal guide. I need to reseal the boom cylinder on my own backhoe. If I have time tomorrow I will start on it and maybe see if it also has a ledge in the barrel. It won't be the first time for it either !
You're right. Something isn't right. Almost looks like an old seal wedged in there...
One time, years ago I had one that didn't want to go past the bevel. I wrapped the piston and seals with a sheet of VERY thin shim stock. The stock allowed the piston to slip past the bevel, then just gently pulled the stock out.
Brass shim stock has worked for me in the past as well. I have also used the same shim stock around the seals with worm clamps (radiator style clamps). As soon as the seals are on, and still warm, I wrap them and tighten for about a half hour. Once removing the clamp, immediately install before the seals expand again. You may need a combination of the above.
If u have a small cylinder or brake hone..?? THAT might knock it down a smidge. Couldnt hurt.. do u see any reason for the "lip"..??
Putting the rod/piston in the freezer overnight may also help.Just make sure you don't get any hydraulic oil on your frozen burger!
Mike Bramel is a professional hydraulic rebuilder and is the one person I know of that can give you a definite answer to your question.Hopefully he will read your thread. His user name is Mikebramel.
Just me but if that rough step is the issue, I would take a 1 inch ball on a die grinder and take that ledge out, the cylinder should have a taper to aid in starting the packing and it looks to me somehow it got roughed up. If you take my advice pack the cylinder with clean rags and after grinding make sure every bit of the grindings are out of the barrel and threads, one piece of grinding in the gland threads will ruin the barrel and gland. you will not be affecting where the packings seal in operation.
I always take a screw clamp and put on piston seal to squeeze seal so it will install easier, when you install seal put clamp on it and tighten down until you get ready to put into tube then take clamp off and grease the heck out of it.
Use a ring compressor to squeeze the seals on the piston side then get some dry ice and immerse the piston and compressor in the ice for 30 minutes this will make the seals contract. Once you are ready to install take compressor off and use plenty of grease and it should slide in and then the seals will re-expand as they warm up. I do this alot in the aircraft industry in order to get seals to go into bores that are super tight tolerances. Its calles sizing the seals.
Dremel tool it, also you are always better off honing a cylinder to break the glaze. Brush research flex hones work well 320 grit you can make extensions as needed, hone it and wash it good. The piston ring on my case 580d was a expandable type. I put them on then put the piston in the cooler for awhile. The material goes back from where you stretch it. The rod and piston require some force to get started. I also have ran into problems with replacement seals that where not exactly right. If your piston seal is a split pst seal put it on with whetherstrip adhesive hold it tight till it sets,a few minutes, then eat lunch and come back and assemble. The cranes i have done all have split piston seals and gluing them is the best bet.
Thanks @moonlight , that piston compressor clamp thing worked! I put it on then waited a day for the seals to shrink down a bit, then put it in. I still had to whack it with a hammer to get it to slide in, but it clearly had less resistance than before. I pulled it out after inserting it a little bit to see if it was deforming the seals and it wasn't so I re-inserted and gave it some taps with a hammer, but it went in. Here's a picture of what I have. It works and doesn't seem to leak. Now I'll put the bucket assembly on and see if it bleeds off over time, but it seems okay so far. Thanks for all the help!
Glad you got it, on my 580D all the cylinders had a nice taper machined in them, one of the Grove cranes I have on the boom cylinder there is a machined out grove before the seal gets in the barrel, terrible design. I think it was for clearance for cutting the thread. We ended up filling it with wax, Gulf wax. We packed it in gave a surface for the seal to go over. ths cylinder was 8 inch diameter, so it was easy to work in the barrel
yeah, that thing you call a "lip" looks exactly like the backup seal that would go under the main piston seal. that shouldn't be stuck in the tube. I am also having the same problem on my 580sk swing cylinder rebuild (and don't have the black ring in the cylinder). I at first thought I have the wrong seal kit. But in the process of removing and replacing the seal, I've damaged it. So new seals arriving soon. The piston seal (item 15) that was in my kit did not have the zigzag cut to allow expansion around the piston and I believe my problem was that it didn't shrink back down enough to be properly compressed in the cylinder.
update: the new seal kit I received did have the zigzag expansion slit, and it worked fantastically! If you already have your seal kit, and the piston seal (item 15 in the diagram) doesn't have the zigzag split, you can order the individual seal here https://www.tractorpartsasap.com/ for my 580sk swing cylinder, item 15 and 16 were bundled together and less than $5 ea.
He already got it together 5 1/2 years ago.
understood, but someone two years from now will still find this thread