Hydraulic Cylinder disassembly

[jedwa1216]

New member here looking for some sage advice. I am attempting to repair the hydraulic cylinder on my dump truck. I have the cylinder off and on the bench. The problem is the cylinder is leaking between the gland and the body of the cylinder. The gland appears to be held on by a snap ring but I have not been able to get the snap ring out. Based on my research here and on other sites on the web I am assuming this gland is threaded on, so if that is true, do I need to thread the gland either on or off some before I attempt to remove the ring? I haven't tried that yet but just thinking out loud here. Here are some pictures of the cylinder, any help is certainly appreciated! https://lh6.googleusercontent.com/--A68ufStzuY/UIrl8xR00WI/AAAAAAAAE7U/BzMkXakyWvg/s903/mini-IMG_0217.JPG

https://lh4.googleusercontent.com/-...AAAAAAAE7c/0HA7VkUM3dM/s903/mini-IMG_0218.JPG

https://lh3.googleusercontent.com/-...AAAAAAAE7k/Hq7Yf7kSJ7U/s903/mini-IMG_0219.JPG

 

[Nige]

Looking at those photos and without being able to see the cylinder physically I would say you are correct, the end cap looks as though it ought to unscrew. Maybe those threaded holes (I assume there are 3 of them) are designed to take some type of wrench that fixes to the end cap and is then rotated while the cylinder is held in some type of clamped fixture..?

 

[Huntoon]

Check out Kieth Fenner's youtube page. He just did a video on this: http://youtu.be/2KGhZgwmgMI

 

[jedwa1216]

Check out Kieth Fenner's youtube page. He just did a video on this: http://youtu.be/2KGhZgwmgMI

Thanks for the link, however, the cylinder I have does not have that slot for the ring to go into. Mine appears to have the ring going in between the gland and body of the cylinder. The second picture in my original post shows the end of the ring near the top of the cylinder. I have been trying to pull that ring out but no success.

Nige, I am making a wrench to do exactly that but until I get the ring out it is no use. I am stuck for fear of messing something up since I don't know exactly how this thing goes together. Thanks.

 

[hunterjust]

You might just need to push the gland in. To get to the ring. That is the way some older cylinders are.

 

[JeremiahSr]

I think the gland will either pop in further or screw in furthur so you can extract the ring then remove gland. The newer little john deere dozers are the same way. They just push in but i do see threads on yours.

 

[jedwa1216]

Woo Hoo!! I got the ring out. You guys are awesome. I had to push the gland in to get the ring out. There are no threads on it so I think now it is stuck on the Oring. Trying to hold the weight off the rod and work it out by myself is not easy! When I get it out I will take more pictures and post them for everyone. Thank you, Jeff.

 

[willie59]

Common problem with disassembling those type of cylinders, the o-ring that seals the gland gets hung up on a burr where the groove for the retainer ring is. I've had those get hung so tight on that groove that I've had to push the cylinder in and out to expel the oil in the cylinder, then push it all the way in, and stick an air nozzle in the extend port giving it a shot of air that shoots rod and gland across shop floor.

Be sure and polish that groove well with emery cloth to remove burrs before you reassemble cylinder.

 

[Justwaiting]

Hello guys, new here myself. I need help from time to time, so I will do my best to offer any help I can as well. I have apx 17 yrs of heavy equipment maintance but 32 yrs of hydraulic experience of all kinds.
I felt compeled to reply after reading the post of useing compressed air to dislodge a rod from the barrel of a cylinder. I don't mean to sound condisending but please this should be avoided if at all possible. Try securing one end of the cyl. to a imovible object and the other end secured to another fixed point via a come along or chain boomer useing the device to pull it out slowly. If you have given up and resulted to the compressed air, then please be very aware of trajectory and anything in its path. Also do it from a remote distance with a length of hose. This means of seperation can be very viloent.
That said, feel free to e-mail me for suggestions and I will get back to you as quickly as possible.
Just

 

[OzDozer]

What Justwaiting said is right on the nail. I've had a stuck forklift tilt cylinder blow apart after it jammed, when we tried to assemble it with a new seal. The seal had been manufactured by a seal supplier, and it was too big.
We used the ole BFH trick to try and separate it, then air as well. We got carried away and forgot to secure the shaft. It finally released with considerable force, and scared the crap out of us - and the air pressure wasn't all that high, either.
Just remember to focus on the potential unseen forces building up, as well as the job in hand. Play safe - you don't function as well with fingers missing or titanium plates in your head.

 

[willie59]

Just to clarify, I'm not suggesting to do this repair with disregard to safety. What I am saying is this particular cylinder design has a penchant for being rather nasty to get the gland out. I have tried the suggested methods of chain boomers and comealongs, which is particularly hairy, as, even though I've taken steps to secure the rod, when they do come apart using boomers and comealongs, you are by default in the area where it pops loose, scares the crap out of ya.

On the other hand, I place the offending cylinder on the shop floor with the rod end pointing into a long cardboard box filled with rags, place the forks of a forklift on cylinder body to secure and stabilize it, then stand at rear of cylinder (away from rod) and inject air in cylinder extend port. Yes, there is a lot of energy when that rod extends and whacks the gland, but when it's finally dislodged and pushes the gland and rod out, the box of rags absorbs the remaining energy rather quickly with very little consequence. I find this method to be far safer than standing at the business end of the stuck gland pulling on the rod with a chain boomer. jmho.

 

[Justwaiting]

You have a very valid point Willie. I suppose my use of the chain and boomers lacked detail. I usually have the barrel secured to my teardown bench with the rod suspended
by a hoist so as not to fall and damage any components. Then I tighten the boomer a link at a time till the rod is in a bind, then from the side I tap the barrel to dislodge the
rust or get the ring groove or burr to cut the seal. By going only a link at a time the rod usually stops before the piston leaves the barrel.
Another way that is pretty safe although some what messy and time consomeing is to extend the rod and fill the barrel with oil and connect a porta power pump to the extend port. If it is a double acting cylinder or has a vent port on single acting you have to plug that port. Be prepared if the whole rod comes out it can get real messy.
There are several ways to accomplish this task and given the pecauctions you detailed I would agree that air is viable but I would still make it my last choice.
I will say that my opion is biased due to the fact that I was almost hit by one of those projectiles when a co-worker chose air and didn't inform anyone of what he was
about to do.
I hope I didn't offend you, if I did I appoligize, my intent was only to inform.
Thanks
Just

 

[jedwa1216]

Thanks for all the replies. I ended up chaining the cylinder to a tree and pulling the gland out with my tractor. Came right out no problem. I got the new oring and a new packing for the rod but haven't had a chance to put it back together yet. Deer hunting is time consuming! Thanks again and I will take some pictures of the reassembly. Jeff.

 

[Tinkerer]

Here is link about two men who used tooo much air when disassembling a cylinder. http://www.fluidpowersafety.com/fpsi_alert-18.html

 

[willie59]

I hope I didn't offend you, if I did I appoligize, my intent was only to inform.

Offend me? LoL, no way, I'm old, ugly, and thick skinned.

If there's one thing that's for certain when working on all manner of hydraulic cylinders, it's that there's no one certain method that applies to all situations. Cylinder size and configuration have as much to do with disassembly/assembly method as anything, one must determine the best, and safest, method for the cylinder being worked on. One must use some degree of caution when working on these units. If they feel they're not comfortable doing the work they should for sure send the unit to a qualified shop.

The link posted by Tinkerer could go in the "are you friggen kidding me?" department. I mean, all the things "not" to do. And one thing I don't do unless I have no other option is get a torch anywhere near a hyd cylinder, especially at the gland end of cylinder. Aside from the fact that the oil is flammable, and the vapors are potentially volatile, I'm not fond of distorting the end of the cylinder barrel by applying heat from a torch. There have been a few cases where a gland I was removing was particularly stubborn to yield to typical methods and I needed to heat the cylinder for expansion, and in a couple of these cases I've used a really hot pressure washer at gland and end of cylinder. After heating it good, gland popped right out.

 

[Tinkerer]

Wille59, That linked article really is unbelievable. The situations described there really are sad and are in the "are you friggen kidding me" category. Unfortunately there are people that do things like that. I never intended to indicate that any of our members has or would even attempt to do what they did.