I have recently acquired my first (2) pieces of heavy machinery. One is a John Deere Backhoe 310c 1980 model. Only problem is the boom cylinder needed a new seal because it was pouring hydraulic fluid. I have never rebuilt a hydraulic cylinder but I usually do all my own mechanic work and after researching it seemed appeared easy. I removed the cylinder after removing the lines of course. Me and a couple buddies took an awesome hydro fluid shower. I removed the ring. I pushed the threaded portion back to locate the lock ring, located it and removed it. Here's where I'm having trouble.....the piston and everything else that I thought would just pull right out after removing the ring won't budge. It slides out to past the threads and just to the edge of the tapered portion and stops and won't move. Has anyone had this issue and please let me know what I'm doing wrong, thanks.
Come along
So the gland and the piston are stuck? Did you see an orange plastic wedge ring before you took out the steel lock ring? that's to fit into the tapered groove to help the seals pass over without grabbing. I've heard of filling that groove with bondo to get the seals past, then cleaning it when the cylinder is empty. Sometimes you can use the cylinder rod as a slide hammer to get the gland loose, but that might make more mess than it's worth if the seals get caught and mangled.
Yep, on those type of cylinders, over time the bottoming out of the cylinder against the gland will cause the snap ring to make a burr in the barrel that won't let the gland come out. Sometimes you can knock the gland down in the cylinder and use some emery cloth to polish the burr away. I've also been known to remove all the oil from the cylinder by working it back and forth, then push the rod all the way in, then throw a blast of compressed air into the port that extends the cylinder, the cylinder will come out with enough force that the piston will knock the gland out from the backside. But be sure the kids and the dog are out of the way because the cylinder rod will jettison across the floor.
light sanding should work, even a small grinder on a dremel to knock down that burr and all the rust / junk that's built up.
Yes, miniature flap wheel on the dremel
Yes when I unscrewed the first ring there was a plastic like ring that was broke and just fell out. I wondered what it was for. The Dremel idea is a good one and also. So I'm gonna feel the groove with spot putty because it hardens but not as hard as bondo, sand it smooth, take the Dremel and clean the cylinder end and push the rod in and shoot it with a blast of air. All great ideas that make complete sense now. Thank you all very much and I will update you guys on how it went.
The plastic ring is supposed to have one break in it so it will go in and come out easy. At least try the ring if you have it. If it slips out of place and gets mangled, then you go to the bondo. You can see the ridge easy enough, or feel it with a small screwdriver. If Willie says it's there, it probably is. You'll need to clean that up before you put it back together, so might as well make it come apart easy.
Air is never a good idea. Very dangerous. You're better off using the machines hydraulics. Yes you will create a mess and loose dollars worth of oil. But you can easily control the cylinder out, the travel is much more predictable, and the force is much greater
Airdro Cylinders in Decatur AL killed a guy doing the air trick
To be clear, I'm not suggesting doing something so dangerous or reckless that someone would get killed doing it. There's inherent risks for a number of things repair people do, from plant maintenance workers, tire changers, mechanics, etc. All things we do must be done with awareness and proper caution. Again, I'm not suggesting doing this in a dangerous manner. With that said, I have done this a number of times on various stubborn cylinders using a rag around the tip of an air nozzle and place it in the port that extends the cylinder then give it a controlled amount of air, I'm not talking about a full blast burst. I'm simply using the piston to knock the gland out, not send it into orbit. Sorry if I caused any confusion.
I have done this many times. I usually tie a chain between the rod a barrel end to prevent the rod from completely escaping.
Uh oh I smell disclaimers on our posts. Lol. I do it with air, a BFH if needed for my handy dandy little 500 pound chain hoist. Sometimes you gotta get mad dog mean to get them apart. Junkyard
Well, not so much a disclaimer, rather, I just wanted to clarify that I wasn't advocating a "hold my beer and watch this!" repair procedure.
If you need more force to get it apart, safely, hook up an airless paint sprayer and pump it up with water, or diesel if you want. It will stop once the piston seal hits the groove. Don't use a pressure washer, there's no bleed off valve if it builds up pressure and doesn't let go, like the priming valve on a paint sprayer. Air gets dangerous when the piston is stuck and the pressure builds up. If the rod moveable by hand and it's retracted all the way when you add the air, it will pop right out. Put air in with the rod stuck extended out and it might build enough stored energy to put the rod through a wall.
You got it exactly Delmer. I never "pressurize" a cylinder with air, very bad idea that can have bad results. Anytime I use this method, I control all aspects of it. First I work the cylinder in and out by hand to push all the oil from the ports. Then I make sure it freely moves in and out by hand. Once I verify this, I retract the cylinder, then give it a brief burst of air which forces the piston out and strike the gland to knock it out. Baby steps, may take several attempts at timing the amount of air to achieve the desired result, but never a full blast and let it go, and never pressurize a cylinder bottomed out on the gland.
I used a come along and the orange ring, it seems the safety ring got held by the fluid port on the end of cylinder, saw a scratch that I buffed out,...Next cylinders I will clean the ring groove a lot more also to let the orange one fit better
For the really stubborn ones, I chain the barrel to the tie down loop on the front off my skid steer and pull the rod out with the loader. A tractor loader or a good shop hoist can do the same job though.