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Hydraulic Cylinder Rebuild

16010 Views 17 Replies 8 Participants Last post by  mikebramel
Need some info on rebuilding these things, they're off my mid 70's Case 644.
Looking at the tops, my lift and/or bucket cylinders may be replacements. They don't look the same, but there's no branding anywhere.

For the bucket cylinder there's an arrow pointing to I guess the end of a ring

The lift cylinders have a shallow groove and a little notch

I have no idea where to start removing the caps on these guys.
I downloaded the Hydraulic Cylinder manual off the stickied topic, but the directions don't seem to mach my cylinders
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These should be a pair of internal and external spiral rings ... sort of like a snap ring but with full 360 degree coverage and multiple wraps.

You might get a better feeling of the clip from the illustration in the parts manual and this link below. (that is not 'the' right ring, just a link to this type of ring)

They appear to be early original cylinders, but I've personally only had the pleasure of rebuilding late model cylinders with the screw on cap.

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If you have unhooked the lines to relieve pressure....On the top one (the picture is not quite clear) remove the light snap ring and tap the gland down into the tube enough to reveal the main retaining ring. It can then be removed with a screwdriver or awl. If it has a lot of hours on it there may be a ridge on the top side of the snap ring groove. You may not need to remove it to get it apart but may want to smooth it up so it doesn't cut the new seals going back together.
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Thanks guys
I haven't removed the cylinders yet, hoping to do them one at a time, remove, repair, reinstall in a day or so.
Ideally, since I'm just replacing seals, it shouldn't take too long -- but it always takes longer than it should.

It struck me as odd that the two caps looked different, but the bucket cylinder is a decent bit larger; hoping they're original, as that's what I have the seal kits for

Googled "remove spiral rings" and found - which made it clearer, cheers. Also makes the cylinder manual make sense, was having trouble visualizing how it was all held together.
If I'm interpreting this right the only tools needed to dissemble these cylinders are a flathead screwdriver and a vice; if so, that's nice.
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The site you linked to is exactly what your up against fish.
I used what I call a pick or I think they call it a scriber.
A screwdriver blade will probably be a little large for the job.
A pair of picks are real handy and about $3 at Sears.


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I tried a pick like CP7 says, but my paws had a hard time holding onto one like that while getting the ring out of the groove. My solution was to take small screwdriver with a handle that I could actually hold while prying around a bit, and ground it down to a finer end than normal, it had almost a knife like edge on it. I'll admit it was a few years ago when I did them , but it really wasn't all that bad a job.

Good luck Fish :)
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Sounds like a little bragging Brian. :fing32:

These may be better for you big hands, big feet guys.
$3 at Harbor Freight.


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You should see my Popeye arms LOL. Now, where's that can of spinach?...

Actually, I have less grip strength since some body damage, so I just find stuff with bigger handles .

Ohh , nice pick set. That would work great.
Hah, I picked up the Craftsman version of the same set - only it was a bit more. Worked nicely

So I've got one lift and the bucket cylinder off and I'm briefly stuck on both of them.

(1) The bucket cylinder's gland was very stiff to push back so I could access the inner spiral ring, now that its free it doesn't want to come out. There doesn't appear to be anything left to impede it, but its rather stuck.
Googling around, it looks like people use an air compressor to force it out. Worst comes to worst I'll give that a shot tomorrow, I'm imagining it becoming a missile with that method.

(2) The lift cylinder came apart easy enough, but the piston is stuck on the end of the rod. It should just unscrew, but I can't seem to budge it. Not sure what to use on it, I'm afraid my pipe wrench will scar it and that would seem less than ideal.


Also, my bucket cylinder's rod has some pitting.

Anything I can do to it, or just leave it be?
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A good hydraulic shop may be able to clean up and replate that pitting, but left alone it will always leak ... seal simply can't get the oil out of the pits ...

I can't offer any rebuilding advise I sent mine out, but scratching or pitting ruins the seal. I didn't have money to replace rod, I was told the scuffing will ruin seal may last 6 months or a year at best after rebuild it lasted 6 months not replacing rod.
Sometimes the pressure on the inner snap ring causes a ridge to form on the tube which makes it hard to get apart. The piston seals will also catch in the groove or the rust from the gland seal out. If you can't get in to smooth it out, you will have to force it apart. It will ruin the seals but you are replacing them anyway. I have used compressed air to take them apart but it is very dangerous. The rod becomes a bullet. I prefer to pull them apart. You can use a engine hoist by securing the base to the legs with a chain and hook the rod to the lifting hook. Apply pressure slowly and tap lightly around the area where the gland is stuck. I have also tied one end to a tree and pulled with a truck. Good luck.
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That pitted rod will seep oil. On a rod that size it is probably cheaper to replace the rod than replate. Some hydraulic shops carry chrome rod and machine it to spec. If you don't have a shop close Baileys Hydraulics will cut chrome rod to length and ship. You can then have any machine shop do the ends as needed.
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These people have several types of pushrod in stock, ship even small quantities and truly seem to appreciate your business. Order it an eight or so too long so your machinist can face it to length.
There was a guy advertising hydraulic repair on craigslist, called him and he wasn't far away; took the freckled bucket cylinder to him and he just kinda shrugged - said he wouldn't mess with it if it were his, but if I wanted a new rod made it'd be $120 or so.
Debating sanding it smooth with a fine grade emery cloth and calling it; a small amount of leakage is acceptable, noming seals every 6 months isn't...
Then again, I'd rather just be done with it.

Ended up using the air compressor to free the gland. Got it set up and applied pressure, then chickened out on the high pressure method when there appeared to be a good deal of pressure and no movement. Applied pressure to the other input, sucking in the piston and alternated between the two a few times, then whacked the gland back into the cylinder a good distance - it slid much easier this time. Applied air again and it shot out with a little thoonk. Woo.
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So an update, I finished it up today.
Only did the one lift and the bucket cylinder, the remaining lift cylinder isn't leaking yet but I suspect its only a matter of time.

It wasn't that bad a job, just took time
And now now more leaks!
I gently sanded the freckled bucket cylinder with 2000 grit emery paper, its as smooth as its going to be. I'll see how long it lasts, the new seals seem to be made of a nicer grade material than the old ones which I removed in pieces. As long as its not emptying the reservoir after 4 hours of running I'm happy for now.

Cheers guys.
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As long as you got the sharp edges and rough stuff off- that will last along time. One of my lift rams was pitted, and leaking a touch- did the same " polish it up " thing, and new seals. Still going fine 3 years later. Just try to store the rams in the retracted postion to keep ' em outta the elements .:fing32:
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Dirt can get into those pits, the wiper wont get them off, then they end up in your system
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