580C can't fit rebuilt ram into cylinder

silverstr8p · Jan 21, 2020

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?

Moonlite · Jan 21, 2020

silverstr8p said:
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?

silverstr8p · Jan 21, 2020

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?

Moonlite · Jan 21, 2020

Yes. I use a piston ring compressor.

silverstr8p · Jan 21, 2020

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?

Moonlite · Jan 21, 2020

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.

silverstr8p · Jan 21, 2020

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

Bls repair · Jan 21, 2020

I are you sure grooves in piston were clean

AllDodge · Jan 21, 2020

Is this an optical illusion or some kind of a lip

Tinkerer · Jan 21, 2020

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.

silverstr8p · Jan 21, 2020

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.

AllDodge · Jan 21, 2020

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)

silverstr8p · Jan 21, 2020

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

thepumpguysc · Jan 21, 2020

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..

Mike85 · Jan 21, 2020

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.

silverstr8p · Jan 21, 2020

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.

thepumpguysc · Jan 21, 2020

& 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.

Tinkerer · Jan 21, 2020

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.

silverstr8p · Jan 21, 2020

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.

Vetech63 · Jan 21, 2020

Take a pic of that barrel I d with it clean. Something don’t look right to me.

580C can't fit rebuilt ram into cylinder

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